REYI5TA DE OBRAS PU
T
•I
'!
'k
jAo i
DE PUERTO RÍCj\J (EjsarTT-.-crrrrrEírxmjB
Camino
''Tierras Nuevas/' de Manatí.
tyl
cAño XII
br
il,
1935
Número
4
^Vi aM'ig?»
Sucesores Saiiturce
—
i:i
iie
vcLCi
708 C-nal
experiencia durante 40 años de
Bank
1,
Tel.
New Orleans, La. New York, N. Y.
Building,
Foot cf Wall Street, LIucllG No.
671.
—
San Juan, Puerto Rico.
técnicos.
?> "<i:
^'- *.- «r^«k.-v*>'4^J
THE SHELL {)FFI(M^]S:
sr.
STEAMSHIP COMPANY
en nuestro propio Laboratorio.
•.-<rx^^^ «^' ^-^^T-^ :
i>::r
THE NEW YORK AND PORTO RICO
Lunkenheimer, Empaquetaduras JohnsManville, Correas de Cuero Bebieren, Herramientas Starret, Aparatos de Pintar De Wilbiss, Grúas Eléctricas Mundi, Maquinaria Frigorífica York, Ladrillos Fuego Tbermo, Reparaciones y Contrastaciones de Romanas. Análisis Químicos Indusproblema con nuestros
i/.í)
i^ira iiii'íírmes diríjase a:
Válvailas
i^^>A:^fy%>:^>^^.^y^-<^>'^-^>"f^- ^"
Güclentc y rápido servicio de vapores entransporte Isxv/ York y Puerto Rico para el
servicio sin interrupción.
Motores de Gas, Bombas para Riegos, Motores Eléctricos Fairbanks-Morse, Romanas Fairbanks.
c^u
CORREOS AMERICANOS
Je pasajeros y carga.
:
Consulte
^=ii: :,r- '4:
.?:-4.^ :?^''í^-
•>-.
^
'*^^-^^"*^^^^^
?
Co.
SAX JIAX. VOXn:.
I.P R.I
.\1AYA(U1^]Z.
PETROLEU!^
Ltd.
CAOrAS, AHECIP>0
PRODUCTS
FUEL OIL DIESEL OIL GAS OIL
MOTOR GASOLINE AVIATION SPIRIT
KEROSENE LUBRICATING OILS LUBRICATING GREASES
ASPHALT FLY SPRAY 'í^v^^^^s,^?»--^-^^
ül
^ús
Puerto Rico
Taleres de Maquinaria, Fundición, Calíleroría y Forja. Constante Surtido en nuestros almacenes de Materiales para Centrales Azucareras.
triales
m ÜU
VAPvOr.ES
LNGENiEilOS CONTRATISTAS
—
gJMüJLiiJi^WJMB
roRiQ
de Abarca i\!irairíar
'
jJg. J.'
'UCñ:
n\
me
Fwmmrrm
MENSUAL
PUBLICACIÓN
Director:
RAMÓN gandía CORDOVA AÑO XII
ABlUh DE
1935.
No. IV.
wmñRim Página. lícport
nj
Counuilia- of Mineral Hrsoitrccs in
!¡K'
Puerto Rico
889
894
(Uoníjios Muniripah's
Preííhiinanj Iicport on
Mineral Devofopment of
ilic
Fue rio Rieo \\y Erhvin V. Kc-kel, Cliief GoologLst, T. V. A.
Mejonnnieiiio en
Pov
11.
la In^JusIria
Estaci/m
Por
la
al
filian
de Horticultura
900
Seeeión de Agrología de la
Experimental
Puerto Rieo
Frutera
T. (/owlor, ProiVsor
¿Qué hen ejido rinde
895
de
la
Universielad de
Pueblo de Puerto Rieo? Ainedee l>onnet, Agrólogo
901
The Maynetife Deposit near lluniaeao, P. R. J>y R. J. 11.
(,V)¡()iiy,
.Alember
A
-
I
-
M
-
E and
A. Meyerhoff, Associated Meiiiber I-M-E
—
¡Aneas Telegráfíeas y TelefóPáginas F entra' es nicas de Puerto Rico.
903
GOBIERNO DE PTO. RICO
BÜLL LINES
OFICINA DEL SECRETARIO EJECUTIVO NEGOCIADO DE MATERIALES, IMPBENTA Y TRANSPORTE
NEW •
SEVICIO SEMANAL DE CARGA YORK-PUERTO RICO Y VICEVERSA
SERVICIO REGULAR DE PASAJEROS
San Juan, Puerto Rico.
Y CARGA
Subasta Semestral
Y VICE- VERSA CIERTO RICO-NORFOLK Y PHILADELPHIA SERVICIO INTERANTILLANO
liALTl MORE-PUERTO RICO
recibirán Ilasty, la fecha y hora fijadas para cada subasta, se sobre cerratlo, proposiciones para suministrar al Gobierno ínsuun precio fijo por unidad, tales cantidades de los diversos arla;,
Pasaje y Carga
ei'.
•
tícrk
ser sus necesidades durante
como puedan
especificados
I
el
se-
mestre do julio 1ro. a diciembre 31 de 1935, ambas fechas inclusive. 8e solicitan artículos para ser entregados en varias poblaciones, enellas Aguadilla, Arecibo, Arroyo, Guayama, Humacao, Isabela, Mayagüez, Ponce, Río Piedras y San Juan. Aquellas personas o firmar, que lo interesen, cotizarán para todas las poblaciones en las
tre
puedan prestar un
cuale-;
servicio
eficiente de entrega,
de acuerdo
con las disposiciones indicadas en cada subasta.
Término para
R\> biist
BULL INSULAR UNE
recibir ofertas
Clasificación de Artículos
.
Mayagüez
Ponce
MUELLE
1935
lu-
f]ncuadernación
ni-
Ferretería, Plomería,
lla-
Provisiones en General, Carnes, Pes-
de
teriales
Frutas,
Muebles v Accesorios Drogas, Productos Químicos, Artículos de Farmacia y Laboratorio .Abonos, Alimentos de Animales, Artículos (le Agricultura y Gana-
noli
6—
dería,
etc.
117—
Artículos
118—
Efectos, Materiales y Utensilios Eléc-
119— 120— 121—
Herramientas en General
122
Efectos de Oficina, Material de Es-
de Bazar y Quincalla, de Barbería y de Zapatería, Efectos para Limpieza, etc.
General
en
tricos
Géneros, Telas, Tejidos, etc. Piezas,
de automóviles
cribanía, etc.
123—
Efectos
de
Dibujo,
Fotografía
9:00
a.
m.
Mayo
1
10:00
a.
m.
Mayo Mayo
1
3:00
p.
m.
2
9:00
a.
m.
Mayo
o
10:00
a.
m.
Mayo
o
2:00
p.
m.
Mayo
2
3:00
p. ni.
Mayo Mayo Maro
a
9:00
a.
ni.
3
10:00
a.
m.
3
2:00
p.
m.
Mayo
3
3:00
p. ni.
Mayo
4
9:00 a
m.
Mayo
4
10:00 a
m.
TEL. 2060
3.
Mayo
4
11:00 a m.
Nuestra Suprema
SAN JUAN
Gasolina, Aceites Combustibles y Lubricantes, Grasas y
Otros
scgarí;
dad y rapidez al públicoj
Nuestra Amable Súplica! Pedir la cooperación del público hacia
m
posible mejor servicio»
gida por
Los modelos en blanco para preparar las licitaciones pueden el Negociado de Materiales, Imprenta y Transporte, San Juan, Puerto Rico.
Ambición:
Servir eficientementet con
Si nuestra
y
Otros
124—
1
Gomas, Tubos, Herramientas
V efectos •
Mayo
Vegetales,
etc.
114—
NO.
Maderas y Ma-
Construcción
Leche,
cado,
Arecibo
Imprenta y
Material de
Pai>elería,
INC.
Hora
Fecha
Núm.
—
SANTO DOMINGO (ÚNICO SERVICIO BISEMANAL DE MUELLE A MUELLE) SERVICIO SEMANAL ENTRE PUERTO RICO E ISLAS VÍRGENES PUERTO RICO
el
amable suplica público,
lizado nuestra
es aco-
habremos rea-
suprema ambición,
obtenerse en
FERNANDO JIMÉNEZ.
WHITE STAR BUS UNE
INC.
Jefe Interino del Negociado. I
VISTA PE OBI A
LICA;
DE
PUEITO MICO PUBLICACIÓN MENSUAL Del Departamento del Interior y de la Sociedad de Ingenieros de P. R. para informar al Pueblo de Puerto Rico, del progreso de sus obras Públicas; para fomentar las industrias e impulsar el arte de construir.
FUNDADA EN
1924
POR GUILLERMO ESTE VES,
E.
C.
Comiisionado del Interior.
OFICINAS:
RAMÓN GANDÍA CORDOVA
San Juan, P. R.
Enitred as second class malter at San Juan, P. R., Jan.
AÑO
SUSCRIPCIÓN
Director:
Depto. del Interior.
2,
ABRIL DE
XII
ANUAL
$«.00
1924 at the Post Office under the Act of
March
3.
1935.
1879
No. IV.
Report of the Committce of Mineral Resources of Puerto Rico By H.
A. Meyerhoff
(Conclusión)
of determining that persistent auriferous
and that the valúes In the north-central section of the Island extending
from Toa Alta to Corozal and Naranjito and as far south as Barranquitas, gold and other metallic minoráis appear to have been introduced inlo the rocks at a nuirber of points where igneous intrusions have invaded the country rock. For the most part the gold seems to have been deposited in quartz veins, most of which are very small, although in certain places and in certain rock t^pes cxtremely numcroiis. Only rarely, a.s in the Barranquitas district, do the veins attain even modérate widths.
The
provision-
drawn that much omes from small but numerous veins which have no com-
al
of the stream gold
inference has been
but thai sufficient concentration may have occurred in a limited number of places to support a Severa! potential localities have inining undertaking. üiercial posí^ibiiities,
been isolated but
none has as
yet been
diagnostically
At the present time some work is being done under the handicap of limited funds and inadequate equipment in the hills about two kilometers north of Ba-
ístudied.
rranquitas.
Two
short
dnfts have been extended inte
the country rock along veins and formatjonal contatt^, but
To
present,
depth.
The
- La Plata district near San Germore promise than any otlier which the Committee has studied. This district was examined and the auriferous rock sampled in 1933, but the Committee suspended hs own work when the Burean of Mines engineers investigated the property and rock samples for assay. Al tliough a report on the results of the assaying was promised, nono has been receiví-J, and the Committee is resum-
mán
ing
date, the Minillas
offers
its
owu
study.
A spetial
report on this locality
Ls
being
prepared.
Summary Pro pecting and mining for gold are the mineral induStry's current boom activities in nearly every part of the world, yet in Puerto Rico interest in this ñeld is virtually lacking, notwithstanding the possibilities cer :
tain sections of the Island are
known to have. Present Information indieates that pannin^^ gnd rocking operations can be triei with g'ood prospects of success along many smalj streams or quebradas in the Corozal--Naranjito sec^ tion and probably in the district south of Mameyes on the northern flauk of the Luquillo Mountains. In the same localities there is
uaneial support,
tions suoaeeding .where thé ^^llUrdal
is assured PÍ gejje^Qug ^seems futile to continué beyo]3.d th^point
at
Committee's efforts have not yet reached a point where a sound opinión can be offered.
unless exploration of this kind it
vems are
justify exploration
some prospect of small
comJSj«rcial opera-
depoeit»*^and wát^r
'^^^/^Jl^f-K^^-^^^^'^^M^:
REVISTA DE OBRAS PUBLICAS DE PUERTO RICO
890
supply are adequate for continuous operation with judiPreliminary results obtained eiausly. selected equipment.
may
be enough fine gold in the extensive alluvial deposits bordering portions of the llío de la Plata to warrant their examination as potential
by panning suggest that there
cities for
dredging.
and quantity in eacb- of the three districts mentioned; and at the present time insufficient exploratory work has been done to warrant any occurrence,
definite conclusión
1933; namely, that the exploratory development of copper for the general trade i^ not warranted. However, there is some current interest in Puerto Rican copper
in
rock sonrces in the Corozal district, the metal appears Seveto be widely disseminated through the country rock. may these ral placeas invite carefnl study, and a few of
which
specific localities
its
demand actual exploration; but none of the work done to date has brought to light any location that has the clearAt the ]y defíned indications of a commercial venture. MiiiiUas La Plata properties near San Germán, on the other hand, commercial possibilities are somewhat more promising, and it is hoped that the laboratory study now -
in
lead to small scale mining operations, and
view, the
Committee
ploration which will
it
is
supervising some preliminary ex-
make
it
possible to reach definite con-
clusions regarding the prospectivo commercial valué of the It Ls hoped that more critical them can be offered in the next genreport of the Committee:
iiewly discovered deposits.
iiiformation about eral
progress will soon yield results that can b© used to Without doubt, the pheno-
whieh bave led the Committee to make these conservative statements would be deemcd ampie to stimulate a tiurry of prospecting and development were they found
may
desirable to determine whether the specific interest in Puerto Rican copper can be satisfied. With this end in
is
PLATIKCM
formúlate a definite opinión. niena.
on these poins.
The condition of the copper market has not improved, and the Committee has not altered the opinión expressed
can at present be designated sls likely sites for rock-mining in the Corozal and Luquillo Although the stream gold ha^ been tracked to districts.
No
concentration,
:
The presence of platinum in the placer has been
deposits of the Corozal district
ííoUl
verified
through the eouí'tesy of Dr. Gilbert H. Ayres, chemist, The quantity recoverable of Norlliamj)ton, I\Iassacliusetts. is small and nowhere, so far as observed, does platinum compose more than one or two pereent of the total metallic Its presence, therefore, seems to be more intercontent. est ing scientifically than commercially.
üu the mainland.
OTHER METALLIC MINERALS In the Committee 's report of January, 1933, oceurrences,
known
NICKEL AND CHROMIUM
or reported, of copper, lead, zinc, silver,
Choniical analyses of
:
discussed.
chromium, and mercury were briefly The investigations of the past two years have yielded new Information regarding some of these metáis,
Mesas have indicated a nickel content of 1.00% and a chromium content of 1.57%. A
but only the discovery of additional copper deposits seems
mium
have any possible economic significance. Laboratory tests have failed to conñrm the presence of cinnabar, the ore of mercury reported near Aguada, and further study of specimens from Barrio del Carmen indicates that the re-
the nickel shows a tendency to range
the above figures indícate
may
ported occurrence of the zinc sulphide, sphalerite, was Pyrite, probably based on an eiíi'oneous Identification. stained and given a resinous luster by a fiilm of limonite,
tential utility of the ore.
The need
seems to have been the mineral which occasioned the mistake, álthough the possibility that sphalerite may be pre-
madé
platinum,
nickel,
to
esnt cannot yet be denied. will be
The
Ihe limonite
recent test in a commercial labórate /y has revealed a chro-
relativo quantities of these
Arriba
in
their geographic extent
occurrences of copper have been -
Comerlo and Coamo
All the deposits consist of sulphide ores,
whieh chaicocite appears to be the principal constituent. Near Ciales the copper has been recovered from several outcrops fícattered over a modérate acreage north and npilhweí^.t of the Ciales - Villalba cñri^tezp^. bsgmnirg spprommately at Kilometer 19 a^id 20. Ir. the Earrajiquitas - Cómerio section, ore life^.,be^n taken frcr: two shallow open along Rio Hondo in B^rio" Las Bocas, and other outcrops are reported. The oi^, .recQvered is high grade, but
mportanee (^¿Ííá3
two constituents
range in the as
wide as
completely alter the pofor systematic sam-
is
apparent
if
an effort
is
to
be
to interest prívate capital in the exploitation of the
deposits.
PYRITE:
Í7i
a3 u¿ual^ its
A
positive results obtained
the Ciales, Barranquitas
districts.
dowimpd from 1%,
pling and analyses to determine these shifting valúes and
.^ummarized under the foUowing heads
COOPER: New
content as high as 1.96% in some of the ore, whereas
with only 0,24% in one of the samples.
«oitireij?'
npon
its
mode
of
Incidental
examination
of
pyritiferous
Adjuntas carretera between. Lares and Rio Blanco has brought to light a low rocks
fodnd
ore of Las
exi)0sed
along the
Lares
-
grade pyrite deposit containning approximately the mineral.
22%
of
Unless the pyrite can be easily and cheaply
concentrated, the deposit possesses
little
potential valué,
can not compete with the higher grade European ores utilized in the sulphuric a cid plants in the Baltinipre for
it
21:í:CLLIANíEOV8 tected
i;i
METALS:
severál copper samples,
Sllver
hM
been de-
and a better idea of
its
significance as a by-prodct in the treatment of the copper ore^ niay be' anticipated if current investigations of th©
REVISTA DE OBRAS PUBLICAS DE PUERTO RICO copper are followed by commercial
tests ,and analyses.
small deposits of lead sulphide (galena)
The
sylvania, have yielded the following results:
known at Barrio
del Carmen and reported in the upland south of Morovis have received on further attention, and no new metallk» minerals of possible industrial interest have been discover-
Something: more has been learned of the titanium ilmenite in the llumacao iro*i ore, in whicli its intímate ased.
.sociation
with tho Iron renders
rather than an
from the
list
a>s.set.
it
a commercial liabiiity,
The elimination
of miscellaneous metáis
of zinc
and mercury
and the
previously known,
failure to
two years of active field and laboratory investigations may be regarded as an indication that the Committee^s work with metallic deposits is becoming well defined, and that it may devoto less of its attention to verification, much of which i¿5 inevitably f ruit less, and concéntrate on the more jmportant quantitative studies which should lead directly into commercial exploitation. discover other metáis not
after
Sample
-
Ignition Loss
ENERGY RESOURCES: Except for extensión of knowledge concerning the lignito deposits outcropping near the ba^e of the limestone cliffs between Lares and Moca, little more can be said regarding the mineral fuels in Puerto Rico than was stated in the Committee's 1933 report. It will be wise to watch the experimenta which are being carried out in Germany and Soviet Russia, where, by the is
0.17
0.10
0.24
0.10
99.67
99.51
99.78
Iron
0.15
0.11
0.05
0.02
Alumina Lime
0.16
0.09
0.17
0.08
Nil
Nil
0.04
may
be pos-
Puerto Rico to profit from their experience in the utilization of her lignite; but there seems to be no point
sible for
in
making prematuro experimental
efforts at the present
na and Arecibo, more especially between Dorado and Barceloneta, and their convenient location with respect to
be appropriately directed toward the
adaptation of hydro-electric energy to the utilization and
The Atlantic Ore Company has recently brought a power line into its mine and mili near Juana Diaz; and if other mining or quarryin^
processing of mineral products.
industries are established on the Island, electrification
the obvious method of handling
With
industrial
power
all
namelj^ a mainland or local market and, shipments are to be made to the mainland, an ocean freight rate which will make competition with Belgian sand possibie.
ware
f actory,
\y
It
is
doubtful w^hether the demand
t'or
glass-
in tlie Island is sufficiently large to support a local
m
but the possibility merits careful study, particular-
connection with a survey of potential uses for hydro
eectric power.
BUILDINO STONE: A
serious effort to determine
the commercial possibilities of Puerto Rican marble has
been made, but without conclusivo
Guayabal Reservoir
Attention has
to
Rio Descalabrado, and hand-trim-
blocks of various sizes have been prepared and some
them shipped
sal.
results.
centered on the limestone rhlge extending from the
be'ín
to
marble firms
in the States for apprai-
Deopile the large surf ace-outcropr^, the marble appearfe a seam of formation slightly less than 300 feet capping the greater part of the mountain in which
to consist of tliick,
the
manganeso is found. Its exposure has led to extensive and a certain amount of subsurface solution, and deformation which it has underguue was responsiblc
solution ihe
is
mechancial operations.
rates low, experimental effort
—
if
of
may
0.02
0.03
The feasibility of cleansing the sand of organic mathas been demostrated, and the utility of the washed product in the making of glass seems assurecl. The large extent of the deposits near the north coast between Caroli-
med
time.
Attention
0.03
ter
being converted to it
Trace
0.01
Magnesia
Once these countries have
perfected the applications of the process,
2
Unwashcd Washed
99.47
Silica
to be solved
synthetic petroleum products.
Sample
1
Uawashed Washed
transportation facilities leave but two commercial problems
NON METALLIC DEPOSITS
process of hydrogenation, lignito
891
may
for the
development of
ly healed.
wisely be turned toward the processing of raw minerals
mauy
cracks which have been part-
'
Because
of the chemical
solution
and
mechanieal
manufactured products. Admittedly ventares of this kind must be based upon minute and accurate studies of local and mainland markets and upon sound industrial engineering but some of the possibil ities, such as the manufsieture of pig iron and steel with the electric furnace,
be considered; and it is not surprising that an elabórate study of the depasits on the property of the Atlantic Ore Company resulted in the condemnation of the marble for
are entitled at least to consideration.
a large commercial operation.
into
;
cracking, there are reiatively few' places on the ridge where large-scale quarrying with channeling machines can even
whole, however,
SILICA 8AND: Burean
Through the copperation of the from local-
of Mines, samples of silica sand taken
near the north coast have been studied for their posAnalyses made sible utility in the manufacture of glass. by the Hazel Atlas Glass Company of Washington, Pen^ ities
it
may
ía vorable site for drilling
have been selected. sified
A
Con^idering the ridge as a
be questioned w^hether a more un-
and study ing the marble coídd
local flexure in the rocks
the fracturing at this point, an
manganeso causes rapid variations make the extraction of any nne color
the
1
ha$ inten the proxiilaity of
in color tha|; would
v^riety in 9§ecified
^r^^^^^ v>gí!?^p^i^í^
REVISTA DE OBRAb PUBLICAS DE PUERTO RICO
892
On
quantities,and sizes utterly impossible.
the local clay employed, the problems are all economie in
either side of
tho mangareé^e property, the joints or cracks are more widely spaced and the color remains essentially constant.
nature.
latter closely resembles that of the Bottieino marble,
The
which
js
small,
extensively used on the mainland and practically
using
all of which is jmported from Italy. In view of the popularity which this type of marble despite the depression, there is good reamaintained has the marble investigations in this section of continué to son
The negativo
the Island.
limited acreage
iiigly
ganeso mine need not,
may
market
concliiisions
may be found
may
ultimately be reached
which seenis
it
is
impossible to
among
^'mLssionary work'^
much foundation
else-
to exist, the
maviufacturer must give consider-
other hand,
is
more
The demand for
tile,
on
active.
Plant loeation assumes a place of great importance not because of
raw materials but because
portation to market.
make
of cheap trans-
Bulk, relativo fragility, and weight
large hauls impossible; and
establish a brick-tile industry,
it
if it is
will be
contemplated to
sounder economy
building
to orect several small plants at strategically scattered points
aetivities of the Federal Relief agen-
demand. There need be little concern about satraw materials although careful sampling and testing must precede and guide the precise loeation of
the
The
:
constructional projects has
made
cement supply one of immediate
the subject of a
interest.
Edwin
C.
Eckel, Chief Geologist of the Tennessee Valley Authority,
made
without
than one or two plants equipped to supply the Island 's
CEMENT local
lh(í
lo-
trades.
cies in
is
;
re-
Sta-
This prejudice
northwestern and southeastem
in the
Whatever the psychological background, the demand for bricks is small and, unless the government program of home construction overcomes the prejudice
for marble slabs and for marble
have never been gathered, and
and some
I
able attention to sales resistance.
guess the possibilities without careful analysis of the market
be warrante
where.
results obtained in the exceed-
aggregate in synthetic stone and concrete products. tisticts
for construction because of the danger of failure
corners of the Island but
which was core-dril led at the manby any means, be assumed to apply
garding the prospects for dimension-block quarrying, a cal
it
brick structures during earthquakes.
in
to the entire ridge.
Whatever
The two principal elements are market and trans* At the present time the market fot brick is and here appears to be some prejudice against
portation.
study of raw materials and potential sites for a cement plant in October and November, 1934, and his report on this and other subjects relativo to the development of rock and mineral resources has obtained wide eirculation. Mr. Eckel hajs concluded that **good cement can be made at a number of points in Puerto Rico", and *'strongly recommends that a government plant be undertaken." The Committee reached the same conclusión
entiro
isfaetory
each individual plant.
a field
concluding in
three years age, '*the creation of a
CEMENT
its
report of 1933 that
industry becomes a problem
which will mean a saving The Committee feek called upon
of economics, the solution of
in
consttruction costs."
to
MISCELLANEOÜS: No made
further
study
has
been
of the other non-metallic products discussed in the
1933 report, but several new^ possibilities have been developed. Some attention has been given to deposits of silica resembling diatomaceous earth, which may find use in
and scouring powders aiyJ other abrasivo proMr. Eckel of the T. V. A. concurs with the suggestion of our Committee to erect a paint mili for the manufacture of mineral paint which will utilizo the limonite of Las Mesas as a base. polishing
ducts.
R ü
reafirm the economie charaeter of the problem, and to
S
U M E
point out the fact that the Eckel report was not desig-
nated to deal critically with the economie factors. The Committee has in preparation a detailled study of the subject which will be published as a sepárate report. It is hoped that the report will serve as a basis for final conclusions and definite course of action regarding the making of cement in Puerto Rico.
CLAY PRODUCTS: A has been given to
somewhat similar Ímpetus consideration of a brick and tile industry
as a result of current housing projects.
a charaeter suitable for brick, d¿.tr:buted,
and
tests
tile,
have already
:r-d:e2,ted
ty cf ene large residual clay depofit at skirts of
Clay deposits of
and pipe are widely the suitabili-
t!ie £Out!ier:i
cut-
Rio Piedras.
Brick and tile manufacture involve the making of a low cost, high-bulk commódity; ajid once the procesa of ipaunfaoture is aáapted to the special characteristics of
Two years of field examination and laboratory research have confirmed the conclusions offered in the Committee report of January 7,1933, although many details and a somewhat different order of importance must be assigned to the six itemized
statements offered at that
time.
Partly because of the data which have been ac(1) cumulated, but even more because of the increased valué of gold in terms of dollars, placer gold seems to offer the. brightest prospects of immediate economie development. Sites mxist be chosen and equipment selected with discretion
;
the element of chance must be f rankly recognized, not
in the p:c¿e::oó cf ¿^cld in
enough
«illuv:u::i to
but in the persistenco ^t valúes sustain operations over a, piriod of
time sufficí^ently long to liquidate the investpient. Intelligent exploration will greatly reduce the risks -— perbaps eliminaet tkem entirely; and the initial invo^t-ment
:
REVISTA DE OBRAS PUBLICAS DE PUERTO RICO is
not large enough to ocoasion any serious ultímate loss. The inereased production of manganese in the (2)
Juana Díaz district, the exploratory work near Adjuntas, and the diseoveries in Bartolo and Aguada point to manganese as a resouree with definite potentialities. A few problems and many milling and metallurgical problems still await solution, and it may be that some of them are But manganese is present and is widely disinsoluble. tributed it will take initiative and some capital to explore its possibilities, and even in the event of failure, the loss
893
capital that will intelligently develop the Islandés mineral resources.
Respectfully submitted, Br.
Ramón Gandía Córdova
Manuel Egozcue Benjamín J. Horton Felipe Carro William D. Noble
Manuel V. Domenech Santiago Claudio
;
may
be greatly offset by incidental recovery of ore. Possibly developments must await more complete recovery of the steel industry, as we]l as a fixed ])olicy with regard
manganese imports on the part of the Federal Government; but exploratory w^ork may wisely be done in advance if it is to enjoy the benefits of an improving market.
Howard A, Meyerhoff
Dr.
Hcliodoro Blanco Guillermo Esteves
COMMITTEE. ¿5an Juan,
Puerto Rico. January 31, 1935.
BIBLIOGRAPIIY
to
The magnetic deposita
(3)
of eastern Puerto Rico are
known, their commercial valué more fully, though not completely, established. Here again exploration should anticípate any possible utility the ores may find in an expanding steel industry; and even though exploration demanda an optimism wliich current conditions to not strictly justify, it acquires pertinence and immediacy when one considers the dwindling reservéis of the Lake Superior dis-
Additional details regarding sources
may
Island's mineral re-
tlie
be obtained in some of the foUowing srtícl^e,
published since January, 1933
GENEUAIi
better
Domenech, Manuel V.: Mines and minerals de Obras Públicas, May, 1934,
p. 625.
el
al
sos
The limonite of Las Mesas and quantitative studies,
(4)
qualitative
terest in its
commercial
still
needs and merits
August, 1934,
Among
—
p. 573.
Recur-
Revista de Obras Públicas,
Minerales de Puerto Rico. p. 691.
as current prívate in-
possibilities demonstraes.
llulhard, Bela:
Geology of the Lares
District.
Revista de Obras Públicas, June, 1934.
(5)
Mjipa de Puerto
cual se indican los Recursos Naturales de la Isla.
Kevista de Obras Públicas, February, 1934.
trict.
now
Puerto Rico. Revista
Ramón: Informe que Acompaña
Crondia Córdova,
Kico en
in
p.
Mineral Resources. C52.
the non-metallic products, the silica sand
possesses an established commercial utility but
seeks a market which prívate enterprise
may
still
Jaclson, Chas. E.: Informe sobre Depósitos Minerales en Puerto Ri-
be able to deco.
velop more effectively than a government committee.
Cement, clay products, and building stone are of immediate interest because of the Federal Relief projects. As industries, however, they demand analytical study of the economic factors connected with their development before the heavy investments they require, are made.
Meyerhoff,
Revista de Obras Públicas, June, 1934,
Howard
A.:
Geology of
p. 665.
Puerto Rico.
University
of
(6)
Puerto Rico.
Monograph, Series B, No.
1,
1933.
NoUe, W. D.: Comité de Recursos Minerales de Puerto vista de
Obras
Públicas, April, 1934.
Rieo.
Re-
Report of Investigations.
787. Revista de Obras Públicas, December, 1934, p.
(7)
be found, abrasives
A
possible outlet for Puerto Rican copper
if
the deposits are adequate; mineral paint and
may
may
offer opportunities for modest business endel
terprises.
Once again the
A
«tressed.
sources
CEMENT
basic needs for accurate data
fabricación de cernenValle Zeno, Bafael: Anotaciones sobre la Públicas, September, Obras Revista de to en Puerto Rico. 1934. p. 730.
must be
volunteer organization w^ithout adequate re-
cannot
expect to carry
investigations rapidly
through to a successful conclusión, for
its
fact-finding
is
Kohle,
W.
D.: Report on a cemnt plant.
November, 1934,
p.
765.
Considerations and studies for a
Puerto Rico.
limited to certain field
government cement plant
minations.
Públicas, Jantiary, 1935, p. 832.
and qualitative laboratory deterFundamental to further progress is a pc;-
manent Insular Burean, with a paid, full-time staff equipped to carry on geologic, mining, metallurgical, and economic investigations, to advise both government and prívate mineral enterprises, and to find and encotirage prívate
Revista de Obras Públicas,
in
Revista de Obras
GOLD Noble, TV. D.:
Metalúrgica del Oro.
Revista de
Obras
Públicas,
-\iW^;:-
REVISTA DE OBRAS PUBLICAS DE PUERTO RICO
894 September, 1933,
Abstract in Mining and
Eng., Tech. Publ. No. 587, 1935.
p. 491.
Report on placer gold investigation of the
Metallurgy, February
district of Corozal
and Naranjito, Revista de Obras Públicas, August, 1934,
1935, p. 114,
p.
Revista de Obras Públicas,
Mvyerhoffy H. A.: Iron in Puerto Rico.
692.
March, 1934, Wright, C. A.: Report of investigations.
December, 1934,
p.
595; May, 1934, p. 635; August, 1934, p. 704.
Revista de Obras Públicas,
MANGANESE
p. 787.
IKON Colony, R. J. and Meyerhoff,
Humacao, Puerto
Rico.
11.
A.:
The Magnetite Deposit near
Howard
Puerto
Obras Públicas, September, 1933
p. 489.
Wright, C. A.: ta de
American Institute of Min. Met.
Manganese
in
Meyerhoff,
A
A.:
Revista
and manganese.
brief report of gold placer
Obras Públicas, October, 1934,
Rico,
de
Revis-
p. 742.
CAMINOS MUNICIPALES La comunicación en
la
isla
entre pueblos es problema resuelto
con nuestras carreteras insulares.
2,000 kilómetros, la
mayor parte de
estos asfaltada, brinda
alberga en su seno virgen.
El impla.ntamiento de centrales azucareras en Puerto Tí ico,
acrecentado en los últimos treinta años, ha hecho
y ha hecho posible
pasar a pocas manos la posesión de tierras fértiles situadas
desarrollo de la agricultura en acjuellas zonas servidas
en las vegas y sobrevegas que antes estaban distribuidas
facilidad a este transporte interurbano el
cía 1 mente se
Su red de
CAMINO MUNICIPAL -DAMIÁN,^' DE OROCOYIS, las
Construido por el Departamento del Interior. nuevas <íonstrueciones)
con su correspondiente contribución al progreso actual.
Pero fuera del alcance de esas carreteras, hay muchos centenares de miles de cuerdas de terreno que no han recibido el bautizo de la "superficie macadamizada'^ del camino que traiga a esas vías establecidas el fruto que poten-
entre
(Típico
d(í
un gran número de propietarios.
Esta centralización de las riquezas, que antes estaban distribuidas, tes
y
disminuyó
el
número de pequeñas terratenienmontañas espe-
estos se fueron a la altura de nuestras
ranzados con posibles explotaciones de terrenos en esa zona.
REVISTA DE OBRAS PUBLICAS DE PUERTO RICO Bien pronto
se dieron
cuanta de que la carencia de
895
de caminos distribuidos en los 75 munieipios de la isla a razón de unos veinte (20) Kilómetros por cada municipio. Esto daría casi un (1) Kilómetro de camino municipal
vías de comunicación limitaba sus actividades agrícolas en esas fincas y se inició la ''espera'' de su construcción para dar impulso a estas actividades. El dinero adquirido con la venta de sus tierras de aba-
afirmado por cada Kilómetro de carretera insular. Para llevar a cabo este plan ise dispuso que
jo sirvió en los primeros años para prolongar la ''espera''
de
y luego, paulatinamente fué decreciendo sementando el niimero de pobres.
La "altura" les o
entusiasmo y
ellos se
la
replegaron
mente de aquellos que
al
corazón de
la isla.
El sueño se transformó en "pesadilla" y nuestros pequeños propietarios de altura, escasamente ayudados por lo» municipios arañaron en las faldas de nuestras montañas "atrechos" y "-veredas" con pendientes y curvas fantásticas por las que "apeaban" a lomo de "chiringos" sus escasos productos agrícolas a costos prohibitivos
Y
venta.
por
estos
para
la
"rasguños" sinuosos en nuestras monta-
que discurren las aguas pluviales son los llamados caminos municipales de barro de los cuales, y como expresión de su gran necesidad, hay inscritos en el Registro del Departamento del Interior más de siete mil ñas,
total
los
el
1ro. de Julio de
1932 exclusivamente en
estudios y construccióu de dicho plan.
ciadam.eule,
menos de
la
Pero, desgra-
sexta (l|6) parte de ese produci-
podido ser dedicado a ese objeto ya que a virtud de
do
lia
la
crisis
por acción posterior de la
reinante, ese fondo,
Legislatura ha tenido que ser usado en su
mayor parte
para atender urgentes nece¿;idades del Tesoro público.
Con
los escasos
fondos disponibles se han podido consuna longitud de 166 Kilómetros
truir caminos afirmados en
y practicar estudios y preparar planos para unos 400 Kilómetros.
las
(7,000) kilómetros.
La
cts.
invertido desde
seguía olvidada y los caminos municipa-
secundarios solo estaban en
"soñando" con
el
el
fondos recaudados por concepto del impuesto de 7 por galón de gasolina consumido en Puerto Rico fuera
los
escasez de caminos secundarios afirmados en Puer-
puede apreciarse sabiendo que solo tiene la 1|10 parte de un Kilómetro de camino municipal afirmado por cada Kilómetro de carretera insular, mientras Francia, por ejemplo, tiene 10 kilómetros de caminos municipales afirmados por cada Kilómetro de carretera nacional. En otros palabras, Francia tiene cien (100) veces más caminos municipales afirmados que Puerto Rico y a ello debe su riqueto Rico
za agrícola proverbial.
Para atender necesidad
tan urgentemente
nue-stra Legislatura decretó el estudio
sentida,
y construcción
del
N'uestros legisladores, convencidos de la imj)ortancia
de este problema y animados del mejor espíritu de cooperación, han aprobado unánimemente en esta sesión de la Legislatura una Resolución Conjunta que abarca la idea de un empréstito a pagarse con la contribución sobre gaso-
una larga serie de años a bajo tipo de interés para acometer en grande escala el plan general de 7,000 kilómelina en
tros de
caminos afinnados.
aprobada en definitiva, como se espereplegados en la ''altura" poagricultores pobres ra, los ''atrechos" y "veredas" transformados en drán ver esos Si esa ley fuese
y en vez del lomo de "chiringos" será que transporten sus productos camiones sobre el chasis de de pobreza y haciénsituación agrícolas, cambiando así su carreteras afirmadas
dola cambiar también a la isla entera.
de Caminos Municipales de la Remayo de 1931. Este plan abarca una longitud de 1,500 Kilómetros
I*lan General Preliminar
Rafael del Valle Zeno,
solución Conjunta No. 74, aprobada en 14 de
Ingeniero Civil.
Prelímínary Report on the Mineral Development of Puerto Rico By Edwin
C. Eckel,
Chief Geologist, T. V. A.
My
visit to
Puerto Rico in October
was designed primarily to study the a cement plant at that island.
-
November, 1934,
possibilities of erecting
But, in the course of that
work, opportunities were offered to study other mineral
and
am, therefore, submitting a preliminary report upon such of thase possibilities as seem, in my judge-
possibilities
I
ment, to be worthy of the consideration of the Insular Government or of any other Federal agency interested in
In suggesting that fitably be undertaken at the moment. developnu'nt of any of these mineral products seems likely to be profitable, I am explicitly leaving off tke question as to
tlie
methods to be adopted
«orne cases,
it
in such development.
In
American
is possible that local or other
can be found'to take up the development in others, seems more likely that government encouragement and control of some sort will have to established in order to se(tapital
;
ií
the order of their actual future importance, but rather in
cnre any progress within our own lifetimes. The Island as exist are is not rich in capital and such accumulations
the order in which I think development might most pro-
in the
the problem.
The items are not
necessarily taken
up
in
hands of people whose
interests like exclusively in
HOSTRANDO LAS LINEAS TELEGRJ .FICAS Y Pan GtQoaiSftKoT
tu
PAftA'ÁCOMPARAft ÍL iNrOR
1^-1953
pin
Jiwn
P.
a.
Junio 9d 1959
"ELEGRÁFICAS Y TELEFÓNICAS
IPAÍUft EU
iNrORMC At^AL 0£
\gS2-lS53
EN OPERACIÓN
.-í'JrPr:? V
''^
cj^-'r»-'! 4 "*,'^,g:??*',/'-j,
,
-
REVISTA DE OBRAS PUBLICAS DE PUERTO RICO
8^8
the unes of sugar, coffee, stfeamships,
utilities,
etc.
Un-
always difficult to secure
der sueh circüninstances it is adequata local backing for a mineral enterprise and still more áifficult to secure honest and capable technical advise
and
It is for these
control.
reasons that I feel
many
mineral possibilities of the Island wiJl have to be, at
of the least,
government supervisión, and some of them niay have to be retained under .such control throu<y-
started under direct
out thf
ir
increasing quantities
and most of them
will be
is
me
PORTLAND CEMENT
—
While on the Island
E
visited a large number of localities and took many samples of limestoneís and clay with the object to deterniining their
m
manufacture of Portland coiueiit. Oidy a few of these samples have as yet been reported on; the remainder are still in the hands of the Burean of Standards at Washington and of the University at Puerto Rico. When the results are^all in hand I will prepare a sepárate report upon the cement possibilities of the Island. In order to meet an emergency, I have submitted, as of November 10, the
a statement covering
my
estimates of costos for a plant
Cataño 'opposite San eluan and the manufacturing costs at such a plant.
built near
of
my
estimates
con-
go over the project of Mr. Aaronson whó government tile works near
to
interested in establishing a I visited
Kío Piedras.
the several possible localities with
Mr. Aaronson and agree entirely as to the feasibility of My suggestion is, however, inaking tile at those points. jhat in building a tile plant, in place of building
entire lives.
m
Island. Mr. Bourne, Ilead of the P. R. E.
While inthe R. A., a.sk
(stablishment to su])ply the entire Island,
utility
used
nection with some government operation.
one large
we keep
in
mind
that transportation costs are high on products which are low píicoíl tor tlipir bulk, and that the breakage on such
producís
í'iay
lopíifpcl in
llic
ín place of one large plant
vcry large,
is
Juan región
í^an
I
would, therefore, suggest San Juan,
that plants of about npial size be iocated near
Mayaguez, Ponce and perhaps other points which have a faii- local market and from which shipments could be made to sinaller towns.
The
entire
amount
not serious; Mr. Aaronson, I believe,
of is
money involved
is
asking that $25,000
I should think that perhaps four, smaller plants could be constructed for not over that total, and that since there is no expert chemical control needed for such products, that one really
be set aside for the single large plant.
three, or
manage all With the exception of this and number of plants, the project
highly trained technical superintendent could
any that where Island the on localities of number large are a there raw as far so undertaken be could manufacture cement
As
a general statement, however,
these hundreds
safe to
considerations, how-
Economic
materials are concerned. ever, limit
it is
rom Cataño. Under such conditions, it government will be profitable if some reliable person in the what possible, manner as service determine, is as quiet a the reavailable in tracts of limestone and clay lands are actual securing The matter of gión, and at w^hat prices. f
options can safely rest until the analyses are received, when we can fix the location more closely. But it would, obiou^ly, be extremely dangerous to have the Information
broadcast that the limestone hilb near Cataño would be
raw material
CLAY PRODUCTS in a large way,
supplies.
— The Island uses chiy products
ranging from common
tile
and brick up
to
There are severa! small tile works the Island, some of which are still in on ready established There
is
to
size
moment.
al-
no great
of good red-burning brick
difficulty in securing supplies
and
tile
MINERAL PATNTS
—
Perhaps the most profitable
small industry in relation of net returns both to capital cmployeJ and to cost of raw^ materials, is the mineral pig-
ment industry. Groung dry colors sell in the mainland markets at from $20.00 per ton upward. In most cases, each can be produced at from $5.00 to $10.00 per ton and they are often made from very common and otherwi^e use;
raw
less
materials,
I
feel that the
Mayaguez
District of
Puerto Rico offers an unusual opportunity in this regard i\ud cannot stress too strongly my suggestion that the
manufacture of paint be undertaken by either government At he request of Señor Menéndez or private interests. November 12, a statement concernprepared, on Hamos, I ing the actual costs of constructing a paint mili,
and
I
a])pend a copy of that to each copy of this report.
household pottery.
operation.
a's
earliest possible
much more bulky product we most
manufacture cióse to good transportation. My feeling is that regardless or whethcr the plant is owned by the government or buiit by a private concern it will almost necessarily be placed on the south side of San Juan Harbor,
the base of our
correction
scems to be entirely worthy of government, attention at the
of possible localities
closely, because, obviously, for a
and not very far
of them, visiting each hi turn.
clays;
it
is
iron ores near iMayaguez are very high grade and xery large tonnages, perhaps up to several hundred million tons. If, in the next decade, the world trade
The
exist in
in
iron should
possible,
indeed, that in the interior portions of the Island whiteburning clays of higher grade may yet be found. But for
our prcsent purposes the chief stress should be laid upon the extensión of ordinary brick, roof tile, drain tile and sewer pipe manufacture. These products will be used in
renew
its
growth there
will
undoubtedly
a time when these ores will be exported in the manuBut, at the present time, the facture of iron and steel.
come
Steel
trade
is
not in need of ores
from new sources
of
I am not counting upon Puerto Rican iron ores as giving any help to the Island within the next ñve years. Under these circumstances, I am stressing the fact hat we can use several thousand tons
supply, so
the development of the
a year of ores in a highly profitable
way
as a basis for
REVISTA DE OBRAS PUBLICAS DE PüEETO RtCO making good mineral pigmants already
discussed. V
SEA SALT
— The Island of Puerto Rico does not con-
producers might be a justifiable govemiaent
áct, botli
the standpoint of expedieney and profit.
As
and
leaS
zinc, the prospects
'
írom
to eopper,
do not seem to be worthy of
any deposits of rock salt, but it has the possibiiity oí" making evapora tecl sea salt very eheaply owing the climatic conditions. At present, or in the very recent past, sea salt has been made at points on the south coast extending from Cabo Rojo, Parguera, Guánica, Ponee, Santa Isabel to
Among the non-metallic mineral products which it seems might be developed are deposits of tale, glass sand, and distimaceous earth and volcanic ash. Of these, I was
Guayama; while
able to visit a
í.ain
at
one point on the northwest córner of manufacturing still imports most
the Island near Isabela
and a large proportion of this coarse form of salted fish a still larger tonnage of salt Ls brought in from Nova Scotia and Newfoundland. ít is my feeling that tho trade in this commodity can be improved very easily in two directions First, the produetion of more salt on the Island should replace the salt Qow imported as sueh. Second, salts produced on the Island could profitable be shipped to Nova Scotia and New-
lurther consideration a the present time.
number of localities of the glass sand but have known oidy from samples at San Juan. feeling, however, is that all four exist in commercial
the oíhers
I
of its fine table salts,
My
salts; while in the
and that their development could be undertaken with reasonable hope of success. In the lack of definite
—
foundland, the
sources of
cliief
our
salt fisch
imports.,
neither of whicli British territories produce salt of their
At present, the sources of supply for the industries are off lie Spanish coast and Turk's Island in the West Indies. íf we would introduce Puerto Rican salt to those own.
we could
í^orthem markets,
Mim,
wiiirli is
oecM [is
both
a!>;(>
iii
receive in return erude gyp-
pro'Juced abundantly in
Newroiindland.
The
oí coiirse, that its
is,
oceau water and
its
fiud
is
simply
simply the heat of the sun.
enough of
I^uerto Kico natiually has
is
Rut
pi'oducts.
both.
ieiiotli
cussed,
PRODUCTS
—
do not intend to suggest hat there were no other
mineíals on the Island whose dev.elopment íibly
In speaking at
on tho four mineral products which have been dis1
be attemptc-e.
í
am
may
not reason-
strongly suggesting that these
four presen t the most attractive features from he standpoint of f^ovemn-^rt ^:^r;^;iirenients
and that
ment shoidd be aided or accomplished
At
present, there
high grade
—
manga nese
is
their develop-
first.
a modérate production of very
ore,
a very small output of gold
and that about covers the actual mineral output of the In my judgment, the manganese shipments are
island.
likely 1o incrcase in
twenty years.
futuro for, perhaps, the next ten or
it is possible that if a
made
more careful study
might suggest government and í^iade of manganese deposits than those which are now woiked. As to gold, 1 have been the working at severa! points and agree entirely with Mr. H. D. Noble that a more extensive output could be .secured by very simple oí'
the situation could be
I
aid merely to the extent of determining the location
m.eans.
I
am
not prepared, however, to
more than
$10,000,
aid to
would be a highly and I certainly
profitable investment for a prívate firm;
the sand, volcanic ash and diatomsceous easth
feel that
have to receive our attention as soon as a cesince all three of them can be used in connection with that cement in the manufacture of superior grades of concrete. tieposits will
ment plant
is built,
-•
In closing this |)relinnnary report
recommend that
I
thínk
it
my
duty
your mineral development lack of local experts on such
to cali attention to the fact that
by the en iré There are excellent
will be retarded
civil and hydraulic engineers on the Island, there are expert sugar chemists and agricul-
matters.
But
1
fio
not
thínk that, today, there
i^
a single geologsit, mining engineer, metallurgist or mineral cliemist
serious
anywhere we are
if
in
Puerto Rico. This deficiency becomes put government money, or en-
lo either
courage prívate capital,
lo take part in the
of Puei-to Rican mineral resources.
I feel
development
that one of the
steps should be the organization of some simple tech-
fii>^t
burean competent to take charge of such matters. It is not necessary, ñor ¡n(;eed desirable, to place such a burean on a very extensive or permanent footing. My feelnical
ing
is
that
it
should be handlel
in
a rather
simple and
inexpensive fashion by temporary details from some of the
maínland organízations and
in case this suggestion
meets
with the approval of the Secretary I should be glad to place the idea in nu)re definite form.
The present commi-
on mineral resources, which seems to be an entirely voluntaiy and unpaid organization, is composed of highly
ttee
honorable and
i)atriotic
gentlemen.
smaller allotments which as gold
I
I feel that
any of the
have suggested for sueh things
mining and similar mining industries could be
placed in the hands of Mr.
W.
D. Noble, Secretary of the
But I do not feel that equipped with eiher competent
committee, with absoluto safety. the committee
is
at present
do much mgre han act minor government allotments. I am personally very deeply interested in this whole matter and
Ihe goveinment go very far in direct operation of such
staff or adequate laboratories to
though 1 feel that supplying proper information and perhaps leasing some items of machinery to actual
as stewards for such
de])osits,
feel justified in re-
grinding mili, which would
I feel that a tale
not cost necessarily
tural chemists.
OTIÍER MINERAL
do not
I
the government extend direct
it
chief advantage of the
raw material
that
prívate producers in any of these four possible mineral
in
plaster and stucco producís. salt industi'v
Scotia and
responsible technical control,
commending
This gy p.sum could be used the local manufacture of
our ceinent mili aiul
iii
Nova
quantities
m
REVISTA DE OBRAS PUBLICAS DE PUERTO RICO
wñl be glad to discuss any of those higher in
it
further
if it
seems of interest to
authority.
Respectfully Submitted
he asked me very specifically for an immediate Under those statement regarding the eeiuent situation. stateaceompany-ing prepared the circumst anees I ha ve in Gruening, Dr. iiieiit and am sending copy to you and to
November
8,
(sgd.)
Edwin
may
be at least equally well informed as to what has been said so far. My personal feeling, from the interview, was that Mr. Chapman and perhaps Secretary Ickes were somewhat strongly inelined toward governníent order that you
C. Eckel,
Chief Geologist, T. V. A.
and that they will examine any commercial critically. But whatever you may decide I think you can feel assured that good and cheap cement can easily be made on San Juan harbor and T wish you every
operation
TENNESSÉE VALLEY AÜTHORITY KNOXVILLE, TENNESSÉE November
offers
10, 1934.
very
snccess in that matter.
Thanking you for
Kis Excellency,
The Governor, San Juan, Puerto Rico.
líiy
visit in
Very
My
dear General
all
the eourtesies extended during
Puerto Rico and
New
I
I
am
respectfully,
:
Edivin C. Eckel,
(Sgd.)
When
York,
saw the Assistant Secretary
Chief Geologist.
of the Interior on
MEJORAMIENTO E N LA
IN DUSTRIA
FRUTERA
Por H. T. Cowles, Profesor de Horticultura
Uno de los entorpecimientos más- grandes con que el frutero se encuentra en su finca es el daño que hacen los insectos
y enfermedades
Se ha estimado que las pérdidas en las toronjas ocasionadas al disminuir la calidad de la fruta han llegado anualmente a la suma de a la toronja.
$100,000 sin tomar en consideración
reducción en la eficiencia del follaje de los árboles atacados por el hongo.
No importa
lo bien
que haya cuajado
la
el
fruto
si las
condi-
ciones climatológicas son adversas, las frutas tendrán que
venderse a
muy
minado en
el
Adoptando un plan deterpuedan asperjarse los árboles a su debido tiempo, muchos agricultores están haciendo un comPor ejemplo, utilizando pulbate eficaz a sus enemigos. verizaciones de caldo bórdeles, se puede dominar el hongo bajo precio.
cual
que causa la roña en algunas plantaciones de
la costa nor-
El período crítico es el intervalo entre la época de la te. floración y la época en que la fruta ha alcanzado un diámetro de unos 3 cm. De acuerdo con las recomendaciones de los investigadores, el frutero puede producir una buena cosecha de toronjas mediante el uso de una solución de azufre con cal cuando se encuentra con el acaro en esta época del año. La concentración más propia para asperjar es una parte de solución de azufre con cal por 66 partes de agua. Se debe aplicar la aspersión cuando hay pocos ácaros presentes,
antes de que ocasionen cosecha,
mucho
daño.
Durante
la
presente
el
noventa
1'^,
siguien-
un frutero de Arecibo pudo obtener
por ciento de su cosecha clasificada "U.
S.
No.
do un programa de aspersión para combatir
los
ácaros de
La solución de azufre con cal ejerce solamente mitad del efecto que puede tener la solución de caldo bórdeles, pero ayuda a reducir el daño que hacen las queroí^as y los ácaros. También^ no causa una reducción severa en los entomomicetas que ayudan al agricultor a disminuir las plagas de queresas. Otro paso importante que pueden abordar los agricultores en el presente es la erosión de los suelos. Al lu
toronja.
la
ti
abajo de evitar
ha prestado atenmayor esfuerzo de parte de
la erosión excesiva se le
ción durante los últimos años
;
de esta isla debe hacerse, si no se quiere queden permanentemente estériles, debido a la pérdida del suelo superficial. Las generaciones venideras también necesitarán un terreno propio para los productos agrícolas. Hasta hace poco, solamente una pequeña parte de la tierra bajo cultivo en las lomas se trataba de tal manera que se pudiera conservar la fertilidad para Demostraciones de cómo hacer terrazas en Utuael futuro. do, San Sebastián y otros sitios se han repetido con entulos agricultores
que
las fincas
siasmo por* parte de agricultores progresistas.
Después
de demostrar que una inversión de $2.00 por cuerda en
REVISTA DE OBRAS PUBLICAS DE PUERTO RICO hacer terrazas para evitar pérdidas de terreno, un agri-
tiernas
año en un proyecto de 200 cuerdas. El valor de una inversión tan pequeña no se puede predecir pero es muy sencillo deducir que se puede esperar un aumento considerable en el valor y fertilidad de la tierra en 10 años.
zas,
cultor ha decidido preparar 27
más
este
Otro método que puede adoptar el frutero es hacer qu4 agua corra por zanjas hechas de acuerdo con el contorno dei terreno, haciendo que el agua se empoce en sitios donde l)uedan recuperarse el cieno y humas que restan a la fertiel
lidad si se pierden del terreno. El costo es solamente $4.00 por cuerda y cuando se implante el sistema propiamente, se ayudará a contener el agua de fuertes lluvias durante la
sequía de la primavera.
Se está progresando en la introducción y desarrollo dé mejores variedades de vegetales y frutos para consumo en el hogar y para exportar al mercado neoyorquino. Hasta hace poco, apenas se podía encontrar vegetales frescos y en abundancia en el mercado local. Ahora, tomates de buena clase, pimientos de calidad mejorada, habichuelas
¿Qué Beneficio Rinde
al
la
y abundantes repollos, como también otras hortalipueden encontrarse en nuestro mercado. Por medio
de demostraciones en las sub-estaciones, el tomate *'Marglobe'', el pimiento ''California Wonder'' y las habichuelas ''Bountifur^ han probado adaptarse bien a las exigencias del
mercado.
Al mismo tiempo nuevas variedades que prometan hacerse necesarias en el mercado, están siendo mejoradas por
Arturo Roque, en la Estación Experimental. El vauna nueva variedad de berenjena resistente a la marcliitez puede alcanzar a miles de dólares. También está desarrollándose una variedad nueva de i)epinillo resistente al añublo que puede añadir como $50,000 al bolsillo del ao-ricultor en los próximos diez años. el
Sr.
lor de
No
se
puede terminar
los trabajos
gorgojo,
esta breve reseña sin
importantes del Señor Seín, en
mondando
la base
de la semilla,
mencionar
combate del como también la el
ventaja del uso de abono para café })ara evitar la caída del grano,
la Sección
Experimental de
901
recomendado por
el
Señor Vicente Medina.
de Agrología de la Estación
Universidad de Puerto Rico
Pueblo de Puerto Rico? Por Juan Amedee Bonnety Agrólogo.
La Sección de a su cargo
el
Agrología, creada en julio
1,
1931, tiene
estudio de los suelos de Puerto Rico.
Programa de Trabajo:
los
El trabajo principal comprende dos fases: 1 Cooperación en la clasificación científica de Rico (Estudio Edafológico). Puerto de 2
— Investigación
clasificación
los sue-
científica
correspondientes es la base
Negociado de Quí-
clasificar los suelos
de labor.
El mapa siguiente demue-stra el progreso del estudio Cada área enumerada fué Por considerarlo conveestudiada independientemente.
técnica.
edafológico desde 1928 a 1934.
ESTUDIO EDAFOLÓGICO La
sificación de. Suelos (Soil Survey), del
mica y Suelos, Washington, D. C. Esta División Federal, hábilmente dirigida y reorganizada por el Dr. C. F. ]^»Tarbut, autoridad mundial en suelos, posee un caudal de treinta y cinco años de experiencia que ha contribuido a adoptar y perfeccionar un sistema científico y práctico para
:
niente, las secciones 1, 2,
de los suelos en unidades
fundamental para llevar a
^ido englobadas en
3, 5, 8, 9,
un informe
13 y parte de la 7
han
parcial que se intitula:
Survey of the North Coast Área, Puerto Rico."
''Soil
ca-
estudios técbo eficientemente una labor organizada sobre obra de esUna labor. de suelos nicos relacionados con los de una servicios los requiere ta magnitud e importancia competentécnicos de compuesta organización adiestrada
Como
la
información ofrecida por el estudio edafolócomo básica para llevar a efecto un
gico es considerada
l)rograma sobre la rehabilitación agrícola del país,
el Se-
cretario de Agricultura de los Estados Unidos ha asignado
el con experiencia en esta materia. Afortunadamente, Rico Puerto de Comercio Departamento de Agricultura y Universidad de y la Estación Experimental Aerícola de la con la proyecto este P. R. vienen, desde 1928, realizando
$15,000 del fondo de elaboración de azúcar de Puerto Rico para continuar durante este año (1935) el estudio edafo-
cooperación conjunta de las centrales azucareras y terrateuiente$ importantes del país, y de la División para Cla-
do estos estudios, en la región occidental que desde Cabo Hojo Añasco se extiende al interior. Se estima que con
tes
lógico.
En
la actualidad, seis técnicos federales bajo la
dirección del señor R. C. Roberts, se encuentran adelantan-
-
.ÜEVISTA DE OBRAS PUBLICAS DE PUERTO RICO
902
una asignación final de $20,000 se cubrirá toda la Puerto Ricd en 1936. ¿
Qué
beneficios ofrece al pueblo
isla
de Puerto Rico,
de
el es-
—
Según progresa el trabajo en las zonas esvamos recibiendo mapas o informes preliminares sobre la extensión y descripción de los tipos de suelos en Oportunamente toda la información obtenida la región. en cada región se englobará en una publicación final conteniendo la clasificación, descripción y distribución én matudiadas,
de suelos en Puerto Rico. Como cada tipo de suelo tiene su correspondiente color en el maEl inforpa, se hace fácil su identificación y extensión. pas, de los varios tipos
me abarca
como base fundamental para
económico-agrícolas de las fincas pequeñas del digno de mención el caso específico de las reco-
los estudios
tudio edafológico? Friynero.
utiliza el estudio edafológico
todos aquellos factores que tienen una relación
íntima sobre la formación de los suelos y sus pasibilidades agrícolas tales como el clima, topografía, profundidad del
Es
país.
mendaciones de suelos apropiados para riego, en el DisLa Hon, Cotrito Adicional para Riego de la Costa Sur. Sr. Luis A. al misión de Riego nombró asesores técnicos Serrano, Director de la Subestación Experimental de Isa^ hela, y al siiscribiente. Comentando el informe presenta-
do por
sobre
el
reconocimiento, a base
hecho en
el
campo durante
los asesores técnicos
del estudio edafológico,
el
mes
Comisión de Rie^
el Secretario de la Hon. nos escribe en carta fechada diciembre 5, 1934: ''La labor de los Técnicos ha sido estimada grandemente poi" los Miembros de la Comisión de Riego y ha servido de base
de octubre 1934, go,
para realizar una selección consciente de las. tierras que el Nuevo Distrito de Riego."
han de formar
:
suelo, geología, presencia
de sales nocivas a
la vegetación,
1
cosechas, erosión, etc.
Segundo.—
Beneficia a los técnicos agrícolas porque poder aconsejar a los agricultores sobre aqueEl llos problemas que afectan a los suelos y sus cosechas. técnico tiene al instante información precisa sobre los suelos
les facilita el
de la región de donde parte la consulta.
Aquellos resulta-
dos experimentales y observaciones de índole práctica-ecoKÓmiea obtenida en una región de suelos conocidos pueden
Las Estaciones Experi-
aplicarse a otros sitios similares.
mentales de la Universidad de P. R., del Gobierno Federal,
y de las Centrales Fajardo y Aguirre, llevan a cabo sus ex])erimentos de abonamiento, cultivos y variedades, a base
de la clasificación hecha en
el
estudio odafológico.
Mu-
chas centrales y colonos planean sus prácticas agrícolas a La División de Suelos y base del estudio odafológico.
Cosechas del Colegio de Agricultura y Artes Mecánicas de
Universidad de Puerto Rico, utilizan los datos del estudio edafológico en las cátedras de suelos y agronomía.
la
Tercero. ti[)0s
—
Ofrece
al agricultor
de suelos en su finca
y
le
información sobre
los
una información valiosa sobre finca que interesa comprar. Cuarto.
— Facilita
Clarificación de la
Congreso Internacional Azucarero llevado a cabo en San Juan de Puerto Rico en marzo 1932. Copiamos del informe presentado por el Dr. W. W. C. jMoir a la Asociación de Técnicos x\zucareros del Ilawaii en octubre de 1932:
''Through the
el
hel]) of the
foUowed by the U. S. Department of Agriculture through the work of Dr. C. F. Marbut. This classification seems to one of the finest bases for land taxation yet put í'orward and on that point alone it reeommends itseli: lo This is a project that should be given US very highly. üul' most earnest consideration." í'urnish
La Sociedad Industrial y Agrícola de Punite-A-Pil
a base del estudio edafológico,
ins-
INYESTIG ACIÓN TÉCNICA:
una tasación más
juiciosa de la
fin-
La Sección de Agrología ha tenido
1
la
confección
de informes y estadísticas agrícolas, sociales, económicas, etc. Es la base para el catastro de Puerto Rico. La Secla
Universidad de P. R.,
.su
cargo
el
si-
— Análisis
envía
— Es de inestimable valor para
a
guiente programa técnico:
Propiedad del Departamento de Te-
Economía Agrícola de
que dimos a sus
pectores agrícolas señores Jantet y Portal, en su inspección de estudios sobre la fase agrícola de la caña de azúcar.
el
químico de las muestras de su(^los <iue personal que tiene a su cargo el estudio edafológi-
co de Puerto Rico
ción de
re,
Uuadalupe, nos escribe en carta fechada febrero 4, 1935. reconociendo el valor inestimable de la información de sue-
valor de los suelos en la
sorería.
Quinto.
P>ureau of Chemistry and Soils
of the U. S. Department of Agriculture, the Insular Ex})eriment Station's soil department has been conducting a soil classification :survey along the lines of that started and
los,
ca para los efectos de contribución o hipotecas sobre la propieJad. De esto pueden dar fe la División de Tasación del naneo Federal de Baltimore en P. R., y la División para la
erior
brinda oportunidad de com-
parar su experiencia agronómica con otros agricultores que tienen suelos similares a los suyos. Presenta al comprador
—
Sirve de base para demostrar al mundo ex que estamos organizados agrícolamente sobre una ba^e sólida y científica al nivel de los últimos conocimientos sobre la agricultura científica. De esto pueden dar fé varios delegados técnicos que representaron a su país en el t^exto.
drenaje superficial y subterráneo, posibilidades de riego,
(1931-1935).
—
2. Adaptación de métodos rápidos para reducir e^ tiempo que toman ciertas determinaciones en el proyecto i.
(1931 -33). 3.
— Estudios
de nitrificacióri en varios tipos de sue-
REVISTA DE OBRAS PUBLICAS DE PUERTO RICO los
de Puerto Rico (1931 4.
-
1934).
¿
— Estudio del suelo en una plantación típica de
5.
—
la síliea
beneficios aporta al pueblo de
Puerto Rico, esos
estudios técnicos? ca-
Aparte de
(1933-1934).
fé.
Qué
903
los beneficios
de índole científica que esos
estudios de investigación aportan a la Ciencia Edafológiea
Estudios sbore la solubilidad de los fosfatos y en suelos situados a diferentes elevaciones. (1934-
podemos enumerar
los siguientes beneficios al
PUBLICACIONES
Primero.
—
Es de suma importancia süplementar
observaciones hechas en
Los resultados obtenidos en
el
proyecto II aparecen
publicados como sigue:
J.
el
las
estudio edafológico con infor-
mación química adecuada para obtener luz sobre la
defi-
ciencia o suficiencia de elementos químicos necesarios pa-
ra
Bonnet,
pueblo de
Puerto Rico.
A. and Villamil, F. A.
Research on
sliort-
ening time without affecting the accuracy of Dyer's modi-
el
crecimiento de las cosechas
;
])reseiieia
o ausencia de
acidez o alcalinidad excesiva que puede ser
i)er judicial
a
una cosecha determinada arastres interiores de los elementos químicos; relación del análisis ([uíniico del suelo ;
fied
metliod for determination in
soiLs,
of phosplioric acid,
lime and potash soluble in eitric acid solution. Agrie, of P. R. 17 (4).
J.
Dept.
con
clima, etc.
el
1933.
Los resultados obtenidos en el proyecto III, sobre nide suelos, aparecerán en el número de abril, 1935 del *^ Journal of Agriculture of the University of
trificación
—
Segundo. La adopción de métodos analíticos cortos y precisos economiza tiempo al personal técnico y dinero a la Institución.
P. 11.''
Un
informe sobre
los
datos analíticos de
los tipos
de
Terceío.
— Los estudios de
suelos en la costa norte de P. R. (proyecto I) ha sido en-
es
tregado a la División del Soil Survey, Washington, D. C,
ciertos tipos. (le suelos de
para ser insertado oportunamente en
la
Cuarto.
Los resultados obtenidos tu
¡ios
<roia
en. el
una plantación
del suelo en
los especialistas
el
nitrificación nos indican si
sulfato de amoníaco
como abono en
Puerto Rico.
publicación final
del estudio edafológico.
d oinformados a
conveniente usar
— Los estudios de
proyecto IV, sobre
(*«-
h)
sílice soluble
han
si-
se
hacen con
típica de café,
de café, en Fomento Agrí-
y Estación Experimental.
el
la solubilidad
de fosfatos y
en suelos situados a diferentes altitudes propósito de determinar un índice de rela-
ción entre los arrastres de estos ciernen ios de la altura a .sitios
niveles intermedios hasta los llanos.
(le
THE MAGNETITE DEPOSIS NEAR HÜMACAO, PUERTO By
R. J. Colonij,^' hoff,-\-
Member A. I. ^I. E., and Member A. I. M.
Associate
(New York
i\leeting,
Deposits of iron are widely scattered in the folded Cretaceous rocks and the associated igneous intrusives of Puerto Rico. Most of them are too small for commercial
development, but a few have aroused spme
economic
interest,
among them
scientific
and
the large body of residual
limonite at the west end of the island near
Mayaguez
1-6
and the mixed hematite and magnetite deposit on the southern slopes of the Sierrade Cayey, about four miles north of xYrroyo. 7-9
Neither of these orebodies has been devel-
oped. ñor hace investigations of the widely distributed deposita of magnetite,
currences of iron
which include all the remaining ocof economic eonsideration,
deserving
proceeded beyond the exploratory stage.
With the
possible exceptioíi of the
Arroyo, the magnetite
and
dioritic intrusives,
is
mixed deposit near
directly associated with andesitic
whioh invade the Cretaceous rock
//.
RICO
A. Meyer-
E.
February, 1935)
section,
iments,
and the bulk of is
it,
occurring in calcareous sed-
clearly of contact-replacement origin.
The small
on Río Portugués, north of Ponce, is found in a limestone band near its contact with an andesite dike. 10-lJ* Two deposits of undetermined valué flank the Utuado diorite batholith; one, on Monte Morales near Utuado, at the northern margin of the intrusión; the other, on the Alto de la ..Bandera between Adjuntas and Jayuya, along its Southern contact with the Cretaceous sedimentary section. dei)osit
By
far the largest series of magnetite deposita
San Lorenzo
is
periphe-
which outcrops over 180 square miles in southeastern Puerto Rico and extends to A band of stratified the neighboring island of Vieques. tuffs, shales and thin limestones roughly parallels the ral to the
diorite,
ncithern edge of this intrusivo, and contact phenomena are conspicuous along the entire length of the belt, a matter
"^i^^m^^^^T^n^^W -
'
REVISTA DE OBRAS PUBLICAS DE PUERTO RICO
904 of 20 miles in Puerto Rico,
tensión into Viequcs
Within
this
is
and more than 50
and torrential wash of the normal ifneous materials on oxide, in comparison with the rapid partial decomposition every side. The phenomenon, indeed, is the usual one in Puerto Rico, where the rate of weathering and erosión is determined in large part by the relativo solubilities of the rock-forming minerals. For this reason the iron deposits generally produce conspicous topographic forms wherever they are exposed to the direct action of the atmosphere
if its ex-
taken into account.
contaet
zone there are more than 20
bodies of magnetite, all of which occur in the calcareous
and several of the deposits associated with the two modérate size and of They have attraeted some attention, excellent quality. and 30 years ago, shortly after the American oecupation of Puerto Rico, they were studied carefuUy; but plans made for their exploitation never materialized. Satisfaet-
strata,
thickest limestone horizons are of
and
Finally,
when
Rican mainland eral
ately coarse granitoid rock with the mineralogic composit-
W.
The quartz, however,
ion of quartz diorite.
component, and there are
many
is
a variable
places within the área of
outcrop in which the rock might more appropriately be classified
as
diorite.
Fettke has noted other variations,
wherein the normal plagioclase radorite
—becomes subordinate
—usually
andesine or lab-
to the accessory orthoclase,
and the rock assumes the aspect of a bornblende granite; or wherein augite takes the places of the typical dark Regional differentiation within broad mineralogic, yet relatively narrow chemical is thus a common feature of the intrusive, but the
brown-green hornblende.
District
Humacao, the
largest town in eastern Puerto Rico, is broad alluvial plain, which overlaps the northeastern córner of the San Lorenzo batholith. The iron crops out on the ridge that forms the southern boundary of the a
.
limits,
extreme variation that led to the differentiation of the
Humacao
iron deposit
is
distinctly exceptional to the gen-
eral range.
San Lorenzo Batholith.
—The
San Lorenzo batholith
about one mile south of the town and
less
than one-half mile west of the highway to Yabucoa.
It
forms the soútheastern shore lino of Puerto Rico, extend-
some 500 yd. south of the Roig sugar mili (Central Ejemplo) and is easily accessible from the cart roads that thread the adjacent cañe fields. The ridge rises abruptly, though somewhat irregularly, above the alluvium to an approximate elevation of 600 ft., and it ascends with similar abruptness above the higher rolling country to the south. It strikes east and west, disappearing toward the east in the broadening alluvial plain, and merging about
from the mouth of Rio Humacao, on Vieques Passage, on the Caribbean. The front that faces the sea is broken by many alluvial re-entrants like the one. at Humacao, and its continuity is further interrupted by two series of sligtly younger granitoid rocks, which Fettke has" named, in the order of their intrusión, the Yabucao granite and the Patillas quartz monzonite. 14 13oth form a series of isolated stocks and apophyses situated at, or near, the margins of the batholith. The gianito is cliaracterized by a*coarse texture and an almost complete absence of ferromagnesian components. In some local ities the quartz and oi'thoclase are micrographically
alluvial flat,
lies
a mile to the west with the elevated surface of the Sierra
de Cayey upland. It
the
not, however,
is
upland, for
spurs in
its
it
a normal spur protruding from
differs
from the many neighboring its length. The
comparativo isolation and in
ing
to the port of Patillas
intergrown; in others micVoperthitic intergrowths of orand plagioclase are found. There are no expos-
linear trend of its relatively level crest suggests a sediment-
thoclase
ary structural control such as characterizes hte magnetite
ures of Yabucoa granite in the immediate vicinity of the
hills in .
rougly rectangular in shape, with an
conformance with the orogenic structures of the CreThe intrusive itself is a médium to moder-
fairly
on
is
taceous rocks.
In connection with the investiagtion, a cursory field study was made 12 of a deposit south of Humacao at the eastern end of the belt, and, in contrast with the geographically associated bodies of magnetite, it was found to be a deposit of magmatic type, with f eatures of suf ficient interest to warrant a study apart from the routine classification accorded the other deposits.
Humacao
The
is
portion
axLs of elongation that trends northwest-southeast, in gen-
Bureau of Mines.
Geology of
Humacao
set-
deposit
of the batholithic intrusión that outcrops on the Puerto
pany changed hands, the project was allowed to lapse, and ha« never been revived. In 1932, shortly after its organization, the Committee on the Mineral Resources of Puerto Rico made a brief examination of the more important magnetite deposits, with the cooperation of F.
general geologic
dominated by the San Lorenzo batholith. 13
the control of the com-
it
Ijee of the
—The
ting of the región surrounding the
ory royalties could not then be arranged with the property owners, and the engineering reports diverged widely on
tonnage estimates.
rain.
General Geologic Setting.
the sedimentary belt to the north and west.
suggestion
is
misleading, for the ridge, like the other hills
in the región,
rock, in
The
is
composed of
ma^ssive, granitoid igneous
which the elements of structural control are entireIts topographic prominence is due, none the differential weathering and erosión; for the ridge
ly lacking. less,
to
coincides with the areal limits of the magnetite,
prominence
reflects
the slow deeomposition
and
of the
its
iron
Humacao and
east,
ridge; the nearest
and another
to the north.
lie
three miles to the south
isolated exposure
is about four miles Occurrences of the quartz monzonilc are
considerably more remote, and for this reason the souc alaskite-aplite dikes which cut the rocks associated with tho magnetite deposit are believed to have been conneeted either
with the granitic phase of post-San Lorenzo inor with the gabbroie a.northosite-pyroxeniíe dif
ti-usion,
.
REVISTA DE OBRAS PUBLICAS DE PUERTO RICO an end-stage concentration residuum. Intruded Stratigraphic Secti(m.\ The granitoid favaded a thick section of Upper Cretaeeous rocks, which axe l'erentiate series, as
—
They are exposed
clominantly voleanic in character. llie
that bound the Humacao and extend from this point
hills
north,
alluvial plain
in
on th^
tq the north coast of
the island without interruption, save for a few dioritic stoclís,
fluvial
section
approximately 9000
is
upward by a
tuffs at the base, foliowed
measured across the dip of the formations, is in most instances considerably less, and in one of the deposits in Barrio Collores de Piedras, the mineralized limestone i» separated from the iutrusive by as little as 600 or 700 ft. of tuff
ft.
Table
tuits, ash,
iíico.
Anciesite
15
and
mium üeveiopment
felsite
ñows and
siils
are
San Miguel
is
and
attained in the área lying immediat-
east of
In the neighborhood of siieeession
far
is
from
ciear.
per Cretaeeous voleanic vent,
Humacao
the stratigraphic
The locality is near an Upfrom which flows and shal-
iow intrusives were promiscuously introduced into the
During the closing stages of eruptive activity, vigorous folding and some thrust faulting occurred, which was immediately succeeded by the series of magmatic invasions already described. Contact metamorphism obscured the sedimentary structures and converted the ñows and pyroclastic materials to an aggregate of chioritized rock, in which flow structure and undest-
section at every
Iron Ore
Las Piedras,
commonly
er granitoid intrusives.
horizon.
P. R. a
Fe203
FeO
ing the nature of the original materials
;
and certain
Only the lime-
of the shales have retained their ident-
and extensive siland mineralization of the former immediately north
despite the süicification of the latter
ication
üf the intrusivo contact.
Contact Ores. ion
is
—Although
the
Upper Cretaeeous
not directly related to the problem of the
magnetite,
sect-
Humacao
acquires pertinence because of the fact that
it
magnetic iron*ore was also introduced into the limestones along the northwestern and northeastem The sedimmargins of the San Lorenzo batholith. 16-19 entary members come into direct association with the (iiorite 011 these two fronts and, notwithstanding a rough
at several points
I)arallellism
between their strike and the trend of contact,
73.30 17.82
5.300
4.82
A1203
tr.
1.22
CaO
0.271
0.30
MgO
0.402
0.35
P205
0.056
0.054
S
0.008
0.03
tr.
0.00
C02 Cu IÍ20 (combined) II20 (free)
0.000
tr.
1.790
1.83
0.17
Metallic iron
99.998
99.894
66.05
65.17
a Analysis by Pattison and Stead, Middlesborough, England. b Analysis
by Edward Riley, London.
The magnetite
of contact origin makes its first appearrange of hills south of the Caguas-IIumacao highway about four miles east of Caguas, where it forma a broken chain of deposits stretching eastward for 12 miles along the border of the batholith. At the easter;^ extremity of the magnetite belt, two parallel series have been formed in he two limestone horizons; but the more northerly band, best developed near the village of Torres, is comparatively remote from the intrusive, and the mineralization is si)otty and limited in extent. The eastérnmost of the contact deposits lies less than 4 miles due north of
ance
the
in the
Humacao
occurrence; and, despite radical genetic dif-
modes of origin and the inevitable cont-mineralogy and chemistry, the two types
ferences in their rasts in their
are clasely related in the time of their formation,
Unfortunately
impossible to compare
the two varieties chemically, for only
silicates,
including garnet, epidote, chlor-
amphibole, pyroxene and tale; but magnetite does not
appear, except in minor quantities wáth hematite, short
and
l)resumably they drew upon the same magmatic sources for their iron.
aggregate of
P. R. b
19.671
uow one formation, now another. Where the diorite im})inges upon the limestone, the latter has been altered to ite,
Ore near Juncos,
72.500
the intrusive cuts irregularly across the strike, penetrating
aií
Esperanza
but in some ca^es
oven the microscope cannot penétrate the metamorphic the formations have assumed.
:
Si02
royed fragmental textures supply occasional clues regard-
ity,
of Contact Ores
stratified series of
Humacao. Dikes and irregular mastíes of andesite porphyry cut the section but in turn are truncated by the San Lorenzo diorite and the youngely to the north
stones
— Analyses
It consists of
mtrecalatea with the stratified formations, and at one horizon they reach a thickness of 500 ft. or more. Their max-
ciisguises
1.
thick in this
5000 ft. of massive ashy shales and two interbedded limestone form-
part 01 Puerto
ations.
from the actual contact ín any of the orebodies. The stratigraphic distance between iron and intrusive, as
of a mile
apophy«es and dikes, not to mention the reeent ísediments which locally bury them.
The
905
it
is
ses of the contact ore are available
analyses of the
Humacao
ore are partial (Table 2).
outstanding point of difference in the contact samples.
two complete analy(Table 1)^ and the
is
One
the abscnee of titanium
Pül?^ REVISTA DE OBRAS PUBLICAS DE PUERTO RICO
906
Table
— Analyses of Humacao Samples
2.
12
in responso to a
crest
14.49 0.49
12.66
FeO
0.11
MgO
0.14
CaO Na20
1.45
K20 H20
0.06
20.22
78.83
20.82
0.93
2.36
1.63
5.35
a R. B. Ellestad, analyst. alaskite-aplite dikes, cutting the rock associated with
the ore. 1.
Gabbroic anorthosite, base of magnetite ridge.
2.
Hornblendic gabbro, 150
3.
Hornblendic pyroxenite, 250
5.
Ore
Local
Guilles provide a few Prominent in the dark-hued and weathered l'resh exposures, from whielí satLsfactory specimens were gabbroic country rock are a few lenslike alaskite-aplite dikes, the freshness and light color of which provide a striking element of contrast to their more somber lithologic The dikes are irregular both in trend and in associates. thickness, but none of those seen exceeds 20 in. from wall to wall. Most of them exhibit gentle to modérate inclinations and severa! were observed to intersect.
ft.
above base of ridge. ft.
(To be continued)
above base of ridge.
Features,
Manuscript received at the
—The
Humacao
orebody
presumablj
lies
and the contact with the Cretaceous rocks a short distance beyond the base of the
ridge, buried-beneath the raile to
rises
Recent alluvium.
A
scant half
from the
fluvial debris, separated
from the
diorite ex-
are faced by a thin
band of altered
which preserve some vestige of an original sedimentary habit. Like all the Cretaceous strata immediately northeast of the batholith, they strike west-norhwest (N.57''W.) and dip moderaely rfortheastward into the broad synclinal fold th;at separates the massive igneous rocks of the Sierra de Cayey Tipland from the highly folded and compressed sediments. of the Luquillo Mountains. The contact is also exposed on the outskirts of Humacao, on the northern side of the tuffs,
At the
which gíves
1
quartz.
is
C.
2
The Limonite Deposita of
Fettke and B. Hubbard:
R.
G. J. Mitchell:
Eico. Trans. A.
I.
M. E. (1919)
Survey of Porto Rico and the Virgin Islands (1922)
Síientific
3
L. A. Smith:
Trans. A. 4 1..
World Production and Eesources
M. E. (1931)
San Juan, P.
E., 1933.
H. A. Meyerhoff: Geology of Puerto Eico. Univ. of Puerto
Eico Mon. 1-B (1933) 134—136; 146—148. 6
H. A. Meyerhoff: Tron in Puerto Eico. Rcv de Obras Pú-
blicas do
Scientific
6,
Puerto Eico (1934) 11, 108—709.
C. E.
7
Fettke: Geology of the
Humacao
District,
Eeference of footiiote
9
H. A. Meyerhoff: Eeferences of footnote
4.
12
By W. D. Noble and H.
an excellent opportunity to study the progressive changes. Quartz completely disappears, and augite becomes first an aecessory and then the dominant ferromagnesian mineral,
184.
5,
132;
footnote
707—708.
H. A. Meyerhoff: Eeference of footnote
these localities the diorite becomes in-
2,
•
8
G. J. Mitchell: Eeference of footnote
From both
Porto Eico.
Survey of Porto Eico and the Virgin Islands (1924)
11
creasingly gabbroii toward the iron deposit, and to the south the numerous exposures along the Yabucoa road off er
of Chromite.
387.
Committeo on Mineral Eesources of Puerto Eico Eept. No.
2-5.
5
I.
10
tint.
1,
292-294.
South
it
ridge,
61, 97.
Geology of the Ponce District, Porto Eico.
within 3|4 mile of the deposit, also normal, but it is notably deficient in
of the magnetite
the intrusive
a strong greenish
'
Mass.
Mayagüez Mesa, Porto
latter point, 1 1|4 miles north of the magnetite
chloritization,
Associate Professor of Geology, Smith College, Northamp-
-¡-
ton,
valley.
deposit, the quartz diorite is normal, save for conspicuous
New
York, N. Y.
the east, an isolated hill of metamorphosed tuff
posures on the Yabucoa road by 250 yd. of river sediments. Still farther east the hills that fringe the Humacao plain
office of the Institute Oct. 23, 1934.
Associate Professor of Geology, Columbia University,
*
occupies a position cióse to the northern edge of the batholithic intrusive
and the steeper slope
produced has proved less hospitable to vegetation. The exposures have undergone considerable weathering, but not enough to obscure the identity of the minerals or the
magnetif erous pyroxenite, 400 f t, above base of ridge.
Geoíogic
greater,
is
ingly coarse toward the orebody.
0.56
:
floor
obtained.
Ti02
Soda
the relief between ridge
side, for in this direction
and valley
textural features of the intrusive, which becomes increas-
7.17
4.
to 34% modérate increase in the calcium content
the magnetite ridge the best exposures are on the
At
75.38
A1203 Fe203
26''
of the feldspar. 3
northern
Si02
from
to the albite twinning, likewise increase
Samples a
ex-
angles of the plagioclase, in sections perpendicular
'tinction
4
The
while the hornblende becomes less conspicuous.
2,
292. 6,
706.
A. Meyerhoff, respectively secretary
and geologist of the Committee. 13
C. E.
15
Fettke: Eeference of footnote
C. E. Fettke:
14.
H. A. Meyerhoff and
District,
Porto Eico.
Islands (1931)
2,
7,
Eeference of footnote I.
Scientific
268—269.
153—161. 7,
159—163.
F. Smith: Geology of the Fajardo
Survey of Porto Eico and the Virgin