Blasting News Q4 2015

Blasting News VOLUME 24 ISSUE 4 2015

IN THIS ISSUE • ViewShot™, delivering beyond expectations • AEL collaborating with Exploblast at Institute of Quarrying Malaysia Conference • Ground response analysis for optimised blasting results

Printed on 100% eco friendly paper

AEL CAPTAINS OF INDUSTRY

Editor’s Note Welcome to the final issue of Blasting News for 2015.

Being one of the leading players in the explosives industry globally, in 2015 AEL ensured it remained relevant to its customers by producing cutting edge innovations and gamechanging solutions that added value to the market it serves.

CONTENTS 3

AEL CAPTAINS OF INDUSTRY: Meet Paul Eagar

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AEL KNOWLEDGE SHARING: ViewShot™, delivering beyond expectations

8

AEL PARTNERSHIPS: AEL collaborating with Exploblast at Institute of Quarrying Malaysia Conference

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AEL THOUGHT LEADERSHIP: EXPLOSIVES TODAY 15 - Safety in surface blasting

14 AEL PAYING IT FORWARD: AEL supports Mandela Day 2015 15 AEL CASE STUDY: Ground response analysis for optimised blasting results

At AEL our mission is to meticulously apply our learning to developing appropriate technology and helping the mining industry use our energy confidently. In this issue, we introduce you to the many ways in which we have aligned to this mission.

Renowned for introducing several new approaches to mining and explosives, AEL’s specialists such as Field Technician, Ashlin Pillay, introduces us to mine modernisation techniques that add value to mining customers. He presents trials with AEL software known as ViewShot™.

Meet Paul Eagar

As we continue to expand our global footprint, our growth strategy in the Asia Pacific region has centred on building the AEL Mining Services brand equity. To this end, AEL collaborated with Exploblast at Institute of Quarrying Malaysia Conference.

To build on our thought leadership series, we present you with our latest issue of the sought-after technical publication, Explosives Today entitled SAFETY IN SURFACE BLASTING, as an insert herein.

We also share news of AEL expanding its South American operations with a renewed focus to growing its already established customer base by going directly to customers with explosives products, on-site support and blasting optimisation. The most recent platform used was AEL’s participation in Exposibram 2015 held in Brazil.

For 2016, we express our commitment to being a dedicated and innovative organisation that serves the needs of its customers.

We hope you enjoy this issue and we welcome your feedback.

Paul is Executive: Initiating Systems Operations.

Role: To develop and implement strategic plans to increase efficiency and effectiveness in the manufacturing of initiating systems.

Professional background: Bachelor of Engineering (Mechanical), Bachelor of Commerce (B.Com) and a Master of Business Leadership (MBL).

In our next issue we introduce Thinus Bierman who is Executive: International.

To offer comments and content suggestions e-mail: eubulus.pillay@aelms.com Happy holidays!

Eubulus Cover image: Panorama of quarry Contact Details: Eubulus Pillay - Blasting News Editor I Tel: +27 11 606 0313 I Fax: +27 11 605 0000 I eubulus.pillay@aelms.com I www. aelminingservices.com

Disclaimer This publication does not necessarily reflect the views and opinions of AEL Mining Services Limited management. The copyright to this publication rests in AEL Mining Services Limited. Other product and corporate names used in this publication may be trademarks or registered trademarks of other companies, and are used only for explanation and to the owner’s benefit, without intent to infringe.

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Blasting News I Fourth Quarter 2015

Blasting Blasting News News II Fourth Fourth Quarter Quarter 2015 2015

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AEL KNOWLEDGE-SHARING

AEL MINING OPTIMISATION

ViewShot™, delivering beyond expectations

by Ashlin Pillay

The current global economic conditions have caused businesses to relook at streamlining their operations to achieve a profitable outcome.

Analysis of the operations resulted in new technologies and methods being implemented to define the efficiency.

With these concerns being at the forefront of the day-to-day business, the mining sector has embraced the concept of utilising technology to improve their operations. Blasting forms one of the major contributors to improving the downstream benefits in mining.

The control of muckpile distribution, uniformity in fragmentation and increased digging rates are but a few of the factors that dictate the efficiency of the beneficiation process. The correct application of the equipment and expertise during blasting will result in a very efficient process.

Software used for delay designs and blast simulations have recently become very prevalent and a crucial part of blasting. This article focuses on the use of software known as ViewShot™ being used at a trial site.

The inception of ViewShot™ was based on the primary requirement to interface a blast delay design to the electronic initiation systems, which is found in the ShotTM product range.

The intention of this software was to eliminate delays caused by manually inputting the blast design and introducing human input errors during blasting. ViewShot™ is developed and

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maintained along with the control equipment in DetNet, a joint venture partner with AEL Mining Services.

ViewShot™ contains multiple features that allow the user to design timing before blasting time. The user is able to either free style a blast design or import the blast design coordinates in a comma delimited (CSV) format. A “helicopter” view of the blast is then presented to the user to create a delay design with the tools provided in the ViewShot™ suite.

The blast is then visually simulated and once corrections are made, the tagging plan may be generated.

Thereafter, this plan is provided to the blaster in charge to commence with tagging according to the blast design in ViewShot™. This ensures that the tagging pattern on the bench correlates to the designed pattern on ViewShot™. The file will be downloaded into the respective Shot™ control equipment in preparation for blasting.

ViewShot™ is primarily used to do blast delay designs. Due to the flexibility of the electronic initiating systems, it was inevitable that there would be a request from a customer who required us to stretch this particular software beyond its conventional operating limits. This particular customer is an open cast platinum operation situated in the North West province of South Africa.

The customer provided six perimeter hole coordinates that defined the perimeter of the blast area. The instruction was that a blast design had to be generated from the information provided in Figure 1.

This request presented an interesting opportunity to explore the capabilities of the ViewShot™ design tools. The customer required control of the spill over material while minimising the backbreak on the High wall.

The ruler tool found in ViewShot™ was used to measure the bench to

Material excavation taking place a day after blasting

Figure 1 - Blast perimeter co-ordinates

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AEL KNOWLEDGE-SHARING

AEL KNOWLEDGE-SHARING

Figure 2 - Initial planned design

Figure 3 - Drilled pattern including channel allocations for DigiShot™ Plus

The drilled holes according to pre blast bench design

Post blast result with minimal spillage of material

Blast design superimposed over the actual bench

AEL team members overseeing the aftermath

Squaring of the last line while moving the pre-split in by 1.5m

Figure 4 - Dual diamond cut chevrons designed for the blast

Figure 5 - Animated feature allowing for blast simulation

determine the dimensions of the intended blast area. A staggered hole design was created for this blast using the customer’s design requirement.

Once the dimension of the blast was determined, it became a simple task of calculating the number of holes required based on the calculated burden and spacing measurement.

The mine accepted and approved the design shown in Figure 2 allowing for the blast pattern to be drilled and completed 7 days later.

A comparison of the designed and actual drilled patterns revealed that 6

there were two rows of drilled holes missing. The perimeter holes were picked up by the survey department when the material in front of the new blast bench was not cleaned out. On completion of the loading process and subsequent inspection it was determined that there were two rows missing from the intended design as a result of excessive back break, thus allowing for additional material excavation from the previous blast.

This did not delay the drilling process as bench preparations had commenced. The charging was done

Material excavation taking place a day after blasting

over a three day period with no delays.

The pre-split was shifted into the main bench by 1.5 m while the last line on the blast was squared off as per requirement by the mine.

technique assists in harnessing and in possible fault diagnostics if required.

It also assists the designer to ensure that the allocation of the number of holes and surface wire length falls within the system parameters.

Due to missing holes and a ragged free face the customer decided to drill additional holes on the first row to ensure proper burden relief shown in Figure 3 above. The ViewShot™ programme enables the user to allocate the different channels of the Control Equipment which are represented by the different hole group colours on the design above. This

To reduce the spillage of material, two diamond cut chevrons, as seen in Figure 4, were proposed to obtain the required results by confining the cast. In this particular blast the two chevrons also generated a secondary pulverisation of the material resulting in the uniformity of material distribution through the

Blasting News I Fourth Quarter 2015

Blasting News I Fourth Quarter 2015

muckpile which improves digging and loading rates. The blast delay design was optimised by the responsible AEL representative according to scientific calculations and their preknowledge of the ground behaviour and environmental conditions.

In Summary The AEL support team on site had highlighted the benefits of electronic initiation systems, blended emulsion and accurate blast design while also reducing the powder factor from previous designs of 1.1 to 0.9 for the AEL blast.

The customer expressed satisfaction regarding the blast fragmentation achieved while stating that there was an improved bucket fill factor as a result of the uniformity in material distribution on the muckpile which contributed positively to cleaning time and productivity.

Acknowledgements: The author would like to acknowledge the contribution made by Kevin Nieuwenhuizen and the North Cluster surface blasting team.

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AEL PARTNERSHIPS

AEL CUSTOMER SATISFACTION

AEL CUSTOMER SATISFACTION

AEL collaborating with Exploblast at Institute of Quarrying Malaysia Conference AEL's growth strategy in the Asia Pacific

After the successful inaugural DigiShot

region has centred on building the AEL

Plus

Mining Services brand equity particularly

account, Mega Quarry (Malacca), carried

to the exhibition. A delegation from the

in the area of market awareness and

out on Saturday 22 August 2015, AEL

Institute of Quarrying South Africa, led

developing business opportunities in

continues to co-operate and collaborate

by Mr Deon Bosman, also attended the

select markets within the region.

with Exploblast.

conference and visited the Explobast/ AEL

TM

blast at an Exploblast customer

Paz, Technical Services Engineer.

There was positive interest from visitors

booth.

Series 4 I No 13

Building on the successes in Indonesia

As part of this collaboration, AEL

and Australia, the AEL Asia Pacific

co-partnered Exploblast in the same

To further invest in the region in terms

team was able to effectively use this

exhibition booth at the IQM (Institute

of skills transfer and customer service,

towards building opportunities for work

Quarrying Malaysia) Conference and

on 18 November AEL delivered training

in select regions within ASEAN, namely

Exhibition that took place in Putrajaya,

for the Malaysia Quarry Association on

Malaysia and Singapore. AEL is proud

Malaysia over 27 and 28 October

Electronics and Blasting Optimisation.

to be in a position to successfully sell

2015, where AEL’s DigiShot Plus

DigiShot PlusTM, control equipment and

strengths in the quarry and civil and

Congratulations to the AEL Asia Pacific

laser profiling equipment to Exploblast

tunnelling markets were showcased. AEL

team for making strides in expanding the

Malaysia.

was represented at the event by Carlos

AEL global footprint.

TM

EXPLOSIVES TODAY

and

SAFETY IN SURFACE BLASTING

by Ken Meiring

Much of the development of explosives technology has been aimed at producing inherently safer explosives initiation systems. However, unexpected events still occasionally occur resulting

The AEL team at the conference

in the release of tremendous forces. Fortunately, this more often results in a “near miss” than an accident.

In this issue of Explosives Today we identify three major potential hazards associated with any blasting operation: • Accidental initiation of the explosives before the blast • Flyrock from the blast • Secondary blasting ACCIDENTAL INITIATION OF EXPLOSIVES This section covers the accidental initiation of explosives in the following areas: • During transportation • During charging operations • After charging operations are completed

Transportation of Explosives from Magazine to Site Explosives have to be transported from the magazine to the blast area in a licenced explosives vehicle. This may be the same vehicle that is used to collect the explosives from the supplier magazine and to deliver to the magazine on the mine.

Transportation of explosives and initiating systems/ accessories may take place in the same vehicle provided the vehicle is equipped to do so, i.e. there is an effective barrier between the two explosives types and that the vehicle has been licensed to do so.

Explosives to be used for the making up of primers should be stacked

The AEL product range on display 8

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Blasting News I Fourth Quarter 2015

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AEL THOUGHT LEADERSHIP

Rule of Thumb Hole diameters

AEL THOUGHT LEADERSHIP

Rock type

Normal

Controlled

Stemming

TYPE OF ELECTRICAL ENERGY

Hard

20

30

Crushed Stone1

•

Hard

30

40

Drill Cuttings

Medium

25

35

Drill Cuttings2

Soft

15

25

Drill Cuttings3

STRAY CURRENT Electric Detonators • Leaking power sources Instantaneous Electric Detonators carried by rails, pipes, cables, (IED) machinery and vehicles • Induced current from high voltage cables into the blasting wire • Conductive ground • Wet conditions • Faulty or damaged cables or connections

RADIO FREQUENCY • Any transmitter such as a cell phone or radio

•

1 Clean Crushed Stone, mean size, 1/10th Hole diameter 2 Crushed Stone, tests show not as effective in medium to soft rock, potential flyrock 3 Columns shorter than 20 d generally cause noise, airblast, flyrock and overbreak.

The optimum stemming length, depends very largely on rock properties and degree of confinement and can vary from about 20 to 60 d.

Figure 1

within the demarcated blasting area for distribution to the blast holes, immediately prior to priming of the blast holes.

Safety During Charging Operations Before any hole is charged, it should first be checked for depth and any obstructions. This should be done using a weighted measuring tape which is lowered down the blast hole.

Re-drilling or backfilling may then be required to ensure the correct hole depths, according to the blast design.

This will ensure the correct stemming and charge lengths can be achieved, thus reducing the risk of overcharging the hole and creating flyrock.

electronic detonators is imperative and this includes not throwing the boosters around on the bench and ensuring the made up primers are placed next to the hole such that they cannot be stepped on or driven over by the mobile charging unit (MMU).

Initiation of Blasts The use of capped fuse initiators has been phased out on many surface mines and have been replaced by shock tube lead-ins (Cluster) or instantaneous electric detonators (IED). IEDs are susceptible to stray electric current, static electricity, radio signals and lightning. Should IEDs be the only possible means of initiation, it is suggested that the

The length of the explosives column in the blasthole should be monitored carefully to prevent the hole from being overcharged and, once the correct charge length has been achieved, effective stemming material is used to fill the hole to the collar.

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IED

After Completion of Charging Operation After all the holes have been charged and connected up, it is good practice to “walk the blast” to make a last physical check. Often faults will be found that could have serious

• • • • •

•

Ideally, the safest method of blast initiation is an electronic detonator shock tube starter, NetShockTM. Table 2 shows the effect of these hazards on the various initiator types and what safety measures can be adopted.

SAFETY MEASURES

•

electric shock tube starter be used as this has reduced susceptibility to these hazards.

STATIC • Most often from ANFO loaded using compressed air • Winter months – dry air in combination with synthetic clothing

IED Shock tube detonators

• • • •

LIGHTNING • Weather, predominantly in Highveld regions of South Africa, Lesotho where electrical storms occur

Direct hit – all products excluding electronic detonators

• •

NetShockTM

•

Electrically bond all rails, cables, pipes, etc.

Check and repair cable insulation Use a low resistance earth Avoid placing blasting cable next to power lines Insulate firing lines and detonating cables from any stray currents and earths Short and insulate all detonator wires until connection has to be made Never use a radio or cell phone while on the bench near a blast Do not carry an IED on your person if you have a radio or cell phone with you Short out the lead wires of the IED whenever you handle an IED within range of a radio or cell phone Use anti-static hoses when loading ANFO and earth the loader prior to charging Use anti-static footwear and clothing Statsafe technology on shock tube starter No synthetic clothing while working with detonators of any kind Employ bad weather/ lightning sensors (should be DMR approved) Suspend all charging or blasting operations when there signs of thunderstorms/ electrical storms and evacuate the bench or shot Disconnect shock tube

An estimate of the distance to the lightning can be obtained by measuring the time between observing the flash and hearing the thunder. Dividing this time (in seconds) by 3 will give this distance in kilometres. When this distance is less than 3 kilometres (9 seconds) then the blast area should be cleared.

Strict observance of these procedures is vital if flyrock is to be kept under control.

Guidelines on a suitable stemming length and stemming material to avoid flyrock, are shown in Figure 1.

Generally, safe handling of boosters and shock tube assemblies or

PRODUCTS AFFECTED

The electronic detonator range (DigiShotTM, DigiShotTM Plus, SmartShotTM) are fully resistant to electric currents and should be used whenever any of the hazards above occur regularly.

Table 2 - Procedures and Safety

Shock tube starter

Blasting Blasting News News II Fourth Fourth Quarter Quarter 2015 2015

Blasting Blasting News News II Fourth Fourth Quarter Quarter 2015 2015

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AEL THOUGHT LEADERSHIP

AEL THOUGHT LEADERSHIP

b. Inadequate Stemming Good stemming contains the explosives gases for a few extra milliseconds thus allowing more of the explosives energy to be harnessed in the rock breaking process. Poor stemming allows gases to vent at very high velocities, projecting rocks from the collar area. c. Under-Burdened Holes This normally occurs when the bench highwall collapses due to overbreak from the previous blast. Geological features also play an important role and the result is excessive forward movement at very high velocities. It can also happen when inclined holes are used with high benches, with the hole wandering too close to the free face.

Figure 2

consequences and also detrimentally affect the blast results. Such faults would include: • Holes not connected into the blast • Shock tube assemblies incorrectly connected • Wrong Trunkline delay used for a particular inter-row or intra-row connection Once satisfied, the blaster is required to clear the area and place the blast guards.

FLYROCK FROM THE BLAST The most important consideration is whether all personnel have been withdrawn to a safe distance beyond the range of flyrock. It is significant that the explosives regulations state “well beyond the probable range of flyrock”. It is left to the blaster’s experience, control of charging operation, and his common sense on what this distance is. All mines have a standard clearance distance for personnel and equipment.

The safe distance depends on a number of factors including: • The hole diameter and mass of explosives contained in each 12

hole • The stemming length, in relation to the hole diameter, and the quality of stemming material used • The initiation system used and how holes are timed Flyrock problems are due, almost entirely, to carelessness in the designing, charging or timing of the blast.

Prevention of accidents due to flyrock should rank as number one priority in any blasting operation not only from a ‘threat to life’ aspect but also to prevent damage to expensive equipment and private property.

The Major Causes of Flyrock Are: a. Overcharging It is very easy to overcharge holes which have become blocked resulting in the column rise of the explosive being more than anticipated. If excess explosives cannot be removed then the layer of sand equivalent to the missing stemming should be placed over that portion of the blast.

Over charging also occurs if the drilled burden and spacing are too small. This is equivalent to under burdening described below.

d. Over-Burdened Holes Excess burden is caused by either poor blast layout or drilling, or by use of too low a powder factor with inadequate stemming. The result is that upward movement of the rock occurs instead of the desired forward throw. e. Poor Timing An out-of-sequence shot is the same as an over-burdened hole.

This situation frequently occurs when the blast is not checked after final connecting up of the holes and holes do not detonate in the planned sequence.

Figure 3 summarises the above points Figure 3 – Guidelines to secondary blasting

Safety After the Blast Misfires rarely occur in well planned and competently carried out blasting operations. Dealing with misfires is an unpleasant task, but one which must be tackled with determination to make future operations safe.

No personnel should be allowed to reenter the area until the danger from the misfires has been eliminated.

The regulation covers the handing of misfires in some detail. It must be remembered however that if a misfire is to be re-primed and detonated then this will usually result in more flyrock than would normally be anticipated as the rock has been fragmented by surrounding holes.

Blasting News I Fourth Quarter 2015

SECONDARY BLASTING

CONCLUSION

Some oversized rock, requiring secondary blasting, may result from the primary blast. If these rocks are to be blasted then they should first be examined to see if they contain any misfired explosives. The amount of explosives required to break the boulder is given in the table depending on whether the boulder is embedded or exposed.

Blasting is a potentially hazardous operation, but the chances of accidents are minimised if normal safety standards are practised. Most of the safety points described in this Explosives Today are in fact covered

by Mining and Explosives regulations and all blasters should be familiar with these.

It is good practice to do a regular

Blasting News I Fourth Quarter 2015

safety audit of a blaster and his crew.

This would help highlight any unsafe procedures that may have crept unnoticed into the daily routine. This can, and does, easily happen in what is often a repetitive task.

The manager of the mining operation should, as far as possible, avoid putting the blaster under excessive production pressures. This could lead to an accident due to short cuts being taken or procedures being ignored.

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AEL PAYING IT FORWARD

AEL CASE STUDY

GROUND RESPONSE ANALYSIS FOR OPTIMISED BLASTING RESULTS

AEL supports Mandela Day 2015 In support of the annual Mandela Day campaign, AEL donated books that address youth-related challenges to high schools in Tembisa.

The books are targeted at Grade 8 and 9 learners, and aimed at highlighting issues facing today’s youth such as peer pressure. AEL believes the learning material will help equip learners with knowledge to confidently combat and overcome these challenges.

In addition to Life Orientation skills provided in the content of the books, learners also have the opportunity to improve their English proficiency through the promotion of reading.

600 books were donated to each school. The schools include

Boitumelong; Ingqayizivele; Tembisa West; and Phomolong Secondary Schools. The donation was well received by the principals and teaching staff who appreciate the valuable content of the books.

AEL’s book drive campaign was supported by the Maths Centre which AEL sponsors to improve maths and science literacy in Tembisa high schools. AEL’s relationship with the Maths Centre has seen schools benefit from teacher development and learner support initiatives which constantly deliver outstanding results in learning outcomes.

“Phomolong Secondary School would not be the reputable learning institution that it is if it were not for AEL’s unwavering support. We

pride ourselves in delivering a 100% matric pass rate which sees a large number of our students pursuing Bachelor’s degrees at the University of Witwatersrand. This investment will enhance our work aimed at ensuring effective teaching and learning so as to improve the quality of education in our schools.” said the school’s principal, Mr Thoka.

AEL representatives were led by Group Human Capital Business Partner, Thabo Nkoane who believes in corporate citizenship and that every day should be Mandela Day. The Maths Centre was represented by Confident Nkwazi and Shepherd Chigogo who are committed to improving the quality of maths and science literacy in disadvantaged communities.

CASE STUDY

CONTACT Simon Tose Global Mining Optimisation Manager +27 11 606 0000 simon.tose@ aelminingservices.com

AEL MINING SERVICES 1 Platinum Drive, Longmeadow Business Estate North, Modderfontein, 1645, South Africa www.aelminingservices.com

BUSINESS CHALLENGE Gunung Bayan Pratama Coal (GBPC) mining operations are located in West Kutai, East Kalimantan, Indonesia approximately 100 km from Melak, the capital of West Kutai. PT Petrosea (PTP), the mining contractor, had an average target production of 35 Million BCM of overburden removal per year.

PTP and PT: AEL had agreed to initiate a project to optimise blasting results at GBPC mine. In March 2014, AEL started an assessment to identify the areas of improvement in order to optimise fragmentation, muckpile profile and reduce back break.

PT Petroleum was running one main pit (Jumbo) at GBPC mine, in which geological conditions were massive sandstone formations with interbedded siltstone and shales. The updip is predominantly hard sandstone with intermittent weathered sandstones and shales but downdip is extremely hard massive sandstones with cross jointing dipping material with predominant shales and weathered mudstones.

The geological conditions, in combination with the blasting process, provided non-uniform fragmentation with coarse material and backbreak, which caused inconsistency in the dig and haul productivities per hour.

SOLUTION The presence of open structures can interrupt confinement and limit the optimum distribution of the energy inside the rock mass, so optimal timing is crucial to improve contention of the gases.

AEL suggested carrying out a ground response analysis in order to obtain data on how the rock mass responds in terms of time to the pressure applied by the detonation in the blast hole in order to determine the optimum timing delay.

To capture the response time of the rock mass, AEL used a laser profiler in combination with high speed filming to gather drill and blast information, which later was analysed with dedicated software.

With the known VoD of the explosive product down the hole and the real burden of the blasthole, the instant of detonation at the precise height of the marker was identified in the video recording so then the lapse of time until the first movement of the rock was determined.

OUTCOME After analysis and calculation with video software the ground response times were established between 2m/s and 5.5m/s. The characteristic timing design for the existing pattern at Jumbo Pit meant that the current burden relief was 6.3ms/m, which was proved to be insufficient as shown by high-speed film which demonstrated scarce inter-row delay. Blastholes from the second row presented release of stemming since the first row had not displaced enough yet.

The delay time between rows theoretically should be between two to three times the minimum response time, therefore higher burden relief was recommended in order to allow enough time for the rock mass to heave and generate free face for the following rows and avoid back break. Quick intra-row delay was also suggested to avoid the loss of gasses between the stratums which also were observed in the filming.

The project continued with the implementation of the suggested timing with the DigiShotTMPlus system as the electronic initiation.

AEL’s Thabo Nkoane, Group Human Capital Business Partner, engaging with teachers and learners 14

Blasting News I Fourth Quarter 2015

Blasting News I Fourth Quarter 2015

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