Goldmining

was only because the other birds were all waiting near the house for scraps which are thrown out for them, and the Hawk had to come near or go hungry.

When the snow began to thaw, the water could not run away as the ground was still frozen hard. Miniature ponds were formed in the fields, and the roads became like rivers owing to the frozen drains.

Now that the land has returned to normal, the early spring flowers are beginning to show through the earth. The snowdrops and aconites are in flower, and it will not be long before the celandine blooms. The birds are singing once more, and it is lovely to hear the Blackbird's evening song again after this exceptionally hard weather. F. Hillyard, Lower VI.

The first aspect to be considered is, of course, the excavation of the ore. In this mine the rock is mainly pyritic shale (shale with an addition of iron pyrites or ferrous sulphide). In this lie the main quartz, gold-bearing veins of which there are three. There are few outcroppings (rocks showing at the surface) and this renders the already hard task of ascertaining the position of the lodes, or veins, underground doubly difficult.

But before approaching the modern aspect of the mine let us go back to the time of the Roman Legions and their conquest of Britain. That time is the earliest period during which the mine is known to have been worked. Evidence has been found in the pieces of pottery and coins and the shape of some adits (tunnels into the hillside). These adits are shaped like a triangle standing on its apex. The reason for this is that the narrow portion at the bottom is wide enough to allow for the feet of a man and the broad upper part is made so as to allow for the shoulders and basket of ore to move to and fro along the adit. The Romans did not employ underground work much ; their main method of excavation being quarrying. The gold vein was lying between two layers of rock, something like the ham in a sandwich. The Romans stripped off the top layer, leaving the naked gold vein exposed. With their crude methods of excavation and extraction it is surprising that the Romans could make the gold workings pay. True, their labour was almost entirely composed of slaves. Also the ancient waste rock dumps, known as " tailings," not slag heaps, which can still be seen, may contain gold which the Romans, with their crude methods of extraction, could not obtain, and which may be " pay-ore " with the modern methods.

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So much for the Romans. After the ore has been excavated it is brought to the surface in trucks or tubs. The large, irregular shaped pieces of rock are then sent into the first of three crushing machines. This is known as the " jaw-crusher." As its name implies, it works on the lines of a jaw. The only difference being that it is the upper half that moves and not the lower. From here it passes to the " cone-crusher." This consists of a large metal cone, open at either end. In the centre is a metal rod set on an eccentric axis. This rod is turned, and in doing so scrapes along the sides of the cone and crushes the ore which is dropped in at the top. Then the ore enters the last crusher. It is the " ball-crusher." This is a large metal barrel set on a horizontal axis. The barrel is lined with steel plates. The rock is sent in at one end, and mixed with it are a hundred or so metal balls like canon balls. The barrel is revolved, and out of the other end comes the ore, by this time reduced to the fineness of cooking flour.

There are two main methods of extraction from this point. The chlorine process has been done away with because of the danger. One takes advantage of the affinity existing between mercury and gold. This is the amalgam process. The finely pulverized rock is added to water, which renders it into little more than very liquid mud. This is allowed to run over copper plates coated with mercury. The mercury absorbs the gold. The mercury is periodically " combed " and the mercury evaporated, and thus the gold obtained. This, with the silver which is almost inevitably found with gold, is sent to the mint, where it is made into bullion.

The other process is done by using potassium cyanide in a very weak solution. The gold, after being dissolved in this, is recovered from the " pregnant solution " by passing it over a catalystic agent, namely zinc filings, which causes the gold to be precipitated. Those are the methods employed in the mines proper. But other methods exist. Everyone has seen pictures of a man kneeling by the side of a river with a pan in his hand. Apart from the work done by the lone " mucker " a large part of the world's gold has been obtained by placer (pronounced " plasser ") mining. the gold is obtained from the beds of streams where it has been brought by the natural weathering agents. The bed is sampled with the well-known pan, and if the tests warrant it, it is worked on a large scale with sluice boxes. These are wooden troughs up to twelve feet long, fitted together so as to form a continuous waterway. At intervals wooden slats are nailed across the troughs about two inches high. These are known as " riffle bars " 30