Gold reef

“ The extraction of reef gold from its matrix is a much more complicated process, and the problem how most effectively to obtain that great desideratum—a complete separating and saving operation—is one which taxes the skill and evokes the ingenuity of scientific men all over the world. ”

“ Much disappointment and loss of time and money may sometimes be prevented if prospectors will realise that all alluvial gold does not come from the quartz veins or reefs; and that following up an alluvial lead, no matter how rich, will not inevitably develop a payable gold lode. Sometimes gold, evidently of reef origin, is found in the alluvial; but in that case it is generally fine as regards the size of the particles, more or less sharp-edged, or crystalline in form if recently shed ”

“ Palmer Billy insisted that as the gold must have come from a reef before it became embedded in the loose gravel of the stream, the proper way to seek for the reef was to follow up the stream, prospecting wherever there was a sign of sand or gravel in the bed, and keeping a sharp look-out for any outcrop of rock which might contain quartz. The mother-reef whence the gold had been washed must be higher up the stream, he argued, and if once they found that, they would be in possession of more wealth than any of them had ever dreamed of possessing. ”

“ As a rule (and one which it will be well to remember) if you cannot find payable metal, particularly in gold "reef" prospecting, at or near the surface, it is not worth while to sink, unless, of course, you design to strike a shoot of metal which some one has prospected before you. The idea is exploded that auriferous lodes necessarily improve in value with depth. The fact is that the metal in any lode is not, as a rule, equally continuous in any direction, but occurs in shoots dipping at various angles in the length of the lode, in bunches or sometimes in horizontal layers. ”

“ February 4.—After the south-eastern corner had been marked with a tall cross, we opened a path from Arábokasu to the trial-shaft. We threw a bridge of the felled trunks cumbering the clearing over the Fía rivulet, and again examined its bed. Gold had been found in it by the women, and this, as usual, gave rise to the discovery of its subtending reef. The whole of the little river-valley extending to the sea should be bought and worked; there is no doubt that it will turn out rich. In the channel we found an outcrop of slates, both crumbling and compact; this is always a welcome sign. ”

“ What is called the "shoot" of gold may be rich for some yards, and then become faint or wholly disappear, perhaps to reappear some yards farther. Thus there must be a good deal of quartz crushed at different points before it can be determined what number of pennyweights or ounces to the ton a given reef, or a given part of a reef, is likely to yield. ”

“ The 'Father of the African Mines,' dating from 1878, lies on the northern third of the celebrated Tákwá ridge, and its concession embraces an area of 1000 x 2000 fathoms. The rich auriferous reef is the backbone of a long narrow line of hill whose diameter ranges between 1,000 feet to 600 where it is pinched. The lode strikes to the north-north-east with a dip of 47o west. The angle of underlay, I may remark, greatly varies in these Gold Coast reefs; some are nearly vertical (82o) , others are moderately inclined (20o to 50o) , and others run almost flat. ”

“ During the three weeks that I had been out, thus far, I had seen but one solitary human being except my two “boys,” the herd who had told me of the gold reef; for, although but a day’s ride from Van Ryn’s Dorp, the region is a very solitary and deserted one, much of the land being brak (alkaline) and unfit for stock to run on. ”

“ Where there are several parallel lodes and a rich shoot has been found in one and the length of the payable ore ascertained, the neighbouring lodes should be carefully prospected opposite to the rich spot, as often similar valuable deposits will thus be found. Having ascertained that you have, say, a gold reef payable at surface and for a reasonable distance along its course, you next want to ascertain its underlie or dip, and how far the payable gold goes down. ”

“ In view of the specimen gold got in such quantity in Moonlight Creek and its upper tributaties, it would appear that somewhere in the area drained by the creek rich gold-bearing reef must once have existed, and probably still exists and will some day reward the efforts of the prospector; but the country is rugged, heavily timbered, and very difficult to get about in, and few men are now willing to face the extreme hardship the investigation of such places entails. ”

“ The gold occurs for the most part in rich chutes, which, taken by themselves, would yield some thousands of ounces to the ton, but which, when crushed in company with the large quantity of poor matrix by which they are surrounded, keep the average yield down to less than one ounce to the ton. As the reef has every appearance of permanence, and the rich patches, though irregular, appear to persist with depth, it is probable that with economical management the mines will be worked at small profits for many a year to come. ”

“ Maxell nodded.
Though a common-law man, he had been associated in mining cases and had made a very careful study of the whole problem of gold extraction.
“It looks right enough to me,” he said, “but as against that we have the fact that some clever engineers have spent a great deal of time and money trying to locate the reef. That there is gold in Morocco everybody knows, and I should say, Cartwright, that you are right. But where is the reef? It would cost a fortune to bore, even though we had the other borings to guide us.” ”

“ But those who have been engaged in practical mining for long, finding by experience that no two mineral fields are exactly alike in all their characteristics, have come to the conclusion that it is unwise to form theories as to why metals should or should not be found in certain enclosing rocks or matrices. Some of the best reef gold got in Victoria has been obtained in dead white, milky-looking quartz almost destitute of base metal. In South Australia reef gold is almost invariably associated with iron, either as oxide, as "gossan;" ”

“ The term "reef" means a bed or stratum of rock, and these Rand reefs are beds of a sort of conglomerate, consisting of sandy and clayey matter containing quartz pebbles. The pebbles are mostly small, from the size of a thrush's egg up to that of a goose's egg, and contain no gold. The arenaceous or argillaceous stuff in which they lie embedded is extremely hard, and strongly impregnated with iron, usually in the form of [Pg 298] iron pyrites, which binds it together. It is in this stuff, or sandy and ferreous cement, that the gold occurs. ”

“ The quartz formation near the little ruin at the Mazoe River has been much worked for gold, and the Manica belt seems to have been even more exploited. Where the high plateau breaks down at Massi-Kessi an enormous amount of alluvial has been worked. The old people must have obtained, from both the alluvial and the reefs, a great quantity of gold to repay them for the work that they did, and there is no reason to suppose that they have exhausted the reefs; indeed, I have seen at the bottom of old workings the reef continuing and carrying visible gold. ”

“ Assuming that alluvial gold is in the main a derivative from reef gold, it is certainly strange that streams flowing in well-nigh opposite directions, and yet rising within very short distances of one another, should be so largely charged with gold, unless they have obtained it from a common source ”

“ Two men were, however, kept on at prospecting, and in September of the same year they made a discovery of reef near the western boundary of the claim and about 1,000 ft. westward of the earlier workings which completely altered the position both in regard to the company and mining generally in the locality. The new reef was 10 ft. in width. A trial crushing was soon taken out of 86 tons, which yielded gold to the value of £688 5s. 6d., equal to 2 oz. gold per ton; and further prospecting showed the reef to extend at least 700 ft. in an east-and-west direction. ”

“ The ordinary non-scientific digger will do well to give credence to this view of the case, and will often thereby save himself much useless trouble. Sometimes also the alluvial gold, coarser in size than true reef-born alluvial, is derived almost in situ from small quartz "leaders," or veins, which the grinding down of the face of the slates has exposed; these leaders in time being also broken and worn, set free the gold they have contained, which does not, as a rule, travel far, but sometimes becomes water-worn by the rubbing over it of the disintegrated fragments of rock. ”

“ In prospecting a reef, a miner walks along the strike of the outcrop, "napping" as he goes, i.e., breaking off with a hammer or pick, pieces of the quartz or ironstone outcrop. Each fragment is carefully examined for the presence of gold, which is nearly always found, if on the surface, in a free state, that is to say, uncombined with any other mineral. If any gold is present, it may occur in small specks as fine as flour, or in large solid lumps as big as one's fist, as in Bayley's Reward Claim, Londonderry, and one or two other mines. ”

“ Now in the case of a reef which has rich shoots a prospector, naturally anxious to make his "show" as alluring as possible to any possible buyer, sinks his trial shaft, on the underlay, through the shoots. And so it might happen, that by carefully selecting the sites of his shafts, he might have a dazzling show of gold in each one, and merely blank quartz between them. ”

“ According to the Mines Reports of 1890, the reef at the mouth of No. 1 adit was 6 ft. wide, but for the 250 ft. driven on averaged from 2 ft. 6 in. to 3ft., and the stone was highly mineralized and showed gold all through. Where struck at the end of the crosscut in No. 2 adit the reef is said to have been 8 ft. in width, but after being driven on for 200 ft. diminished to 4 ft. 6in. The stone in this level did not show so much gold as in the upper level, but in constructing a pass up to No. 1 good gold-bearing stone was met at 50 ft. up. ”

“ Accordingly, assuming that a fair proportion of the quartz reef gold-fields turn out well, it may be predicted that population will increase in and round them during the next ten years, and that for some twenty years more this population will maintain itself, though of course not necessarily in the same spots, because, as the reefs first developed become exhausted, the miners will shift to new places. ”

“ Some quartz carrying gold-values was said to have been found on the surface, and a drive was put in on it. One ton of the stone is reported to have been crushed for a yield of 4 oz. 2 dwt. gold. The adit was carried in for 223 ft., but as the reef was driven on it became very poor, and after doing some little further prospecting on the same formation at a few feet greater depth the syndicate became discouraged, and once more the claims were abandoned. ”

“ It must be remembered that in these mining districts the gold occurs in quartz-reefs. Comparatively little is found in alluvial deposits, which in California and Australia and the Ural mountains have often been more important than the quartz-reefs. None at all is found diffused equally through a stratum of rock, as in the Transvaal. Now, quartz-reef mining is proverbially uncertain. The reefs vary not only in thickness, but also in depth, and it is not yet certain that any go very far beneath the surface. ”

“ As a matter of fact, there is a regular science to help a good prospector in hunting for reef or quartz gold. Whether he will [Pg 234] find it in sufficient quantity to make the deposit worth working is quite another matter.
"You mustn't think, Jim, that gold happens to be in one place and happens not to be in another as a result of mere chance. There's no chance in Nature. We think there is, sometimes, merely because the factors are so terribly complicated that we can't follow them all. ”

“ The Peak Hill Reef, from 331 tons of stone crushed 2621 ounces of gold; Daisy Bell, 82 tons, gave 1245 ounces; Golden Chimes, 195 tons, gave 1402 ounces. The Horseshoe and the Golden Patch are supposed to be the two richest spots in the colony. Some of the specimens taken from the Patch are not only rich but vastly interesting in other ways, some of the pieces being not gold held together by quartz, but vice versâ; the small pieces of quartz, if tapped by a hard substance, vibrate like a tuning-fork. The gold is very brilliant, and positively sparkles in the light. ”

“ I am also much interested in the terminus of the great Trans-Australian Railway which links you with the eastern States of the Commonwealth."
Before leaving Kalgoorlie the Prince visited workings on the forty-foot thick reef of the "golden mile" which is being gradually nibbled away. [157] This reef, since its discovery a quarter of a century ago, has produced seventy-four million sterling of gold. The profit of working it has not kept pace with the increased cost of labour and machinery, but continues to be appreciable, and large masses of paying quartz are still in sight. ”

“ A five-stamp battery was erected, and from an adit driven at a depth of 50 ft. below the first-located outcrop 30 tons of quartz were taken out, which on being crushed yielded 70 oz. gold. Three lines of reef, known as the eastern, central, and western, were found on the claim, but although one formation was up to 12 ft. in width, and a small crushing of 16 tons from another gave a return of 2 oz. 7 dwt. gold per ton, development on all the reefs proved so disappointing that in 1895 the claim was abandoned and the plant disposed of. ”