To The Gold Coast for Gold Volume II Part 17

His long captivity at k.u.masi, where to a certain extent he learned the Oji speech, familiarised him with the native processes; and thus a Frenchman taught Englishmen to work gold in a golden land where they have been domiciled--true _faineants_--for nearly three centuries. He came out in the Dries of 1877 with the intention of dredging the Ancobra River where the natives dive for the precious metal. He was working in western Apinto, a province of Wasa, under Kofi Blay, a va.s.sal of King Kwabina Angu, when he was visited (January 1878) by Major-General Wray, B.A., Colonel Lightfoot, and Mr. Hervey, who were curious to see the work. They remained only till the return of the mail-steamer, or about five weeks. The General left with some first-rate sketches; the Colonel caught a fever, which killed him at Madeira; and the Esquire, who bears a name well known in Australia, returned to the Gold Coast for the purpose of writing not unprofitable reports. M. Bonnat was presently informed of the Takwa Ridge, mines well known for a century at least to Cape Coast Castle, and ever the princ.i.p.al source of the Axim currency. They were still worked in 1875 by the people who drew their stores from Axim. A five-weeks' residence convinced him that they were rich enough to attract capital; he went to Europe, and was successful in raising it. Thus began the Takwa mines, where, by a kind of irony of Fate, the beginner was buried.

M. Bonnat wisely intended to open operations with wet-working. At Axim I was shown a model flume, made to order after the plans of a M. Boisonnet, or, as he signs himself, 'boisonnet.' He was reported to be a large landed-proprietor who had made a fortune by mining in French Guiana. He proposed for M. Bonnat and himself to secure the monopoly of washing the Protectorate with this flume--a veritable French toy, uselessly complicated, and yet to be used only upon the smallest scale. We must go for our models to California and Australia, not to French Guiana.

The following will be the implements with which the natives of the future must do their work on the Gold Coast:--

The pan begat the cradle, a wooden box on rockers, shaped like the article which gave its name. It measures three feet and a half by eighteen inches, and is provided with a movable hopper and slides. Placed in a sloping position, it is worked to and fro by a perpendicular staff acting as handle, and the grain-gold, a metal seven times heavier than granite, collects where the baby should be. As some flour-gold is here found, the cradle-bottom should be cut with cross-grooves to hold mercury; and the latter must be tempered with sodium or other amalgam.

The cradle begat Long Tom and Broad Tom, the 'tom' proper being the upper box with a grating to keep out the pebbles. 'Long Tom's' body is a wooden trough, from twelve to fourteen feet long by a foot or a foot and a half broad, with ripples, riffles, or cross-bars. There is usually another grating at the lower end to intercept the smaller stones. The machine is fixed in a gently sloping position, at an angle determined by circ.u.mstances; the wash-dirt is lifted into the upper end by manual labour; when stiff it must be stirred or shovelled, and a stream of water does the rest. The greater gravity of the gold causes it to be arrested by the riffles. Instead of the bars grooves may be cut and filled with quicksilver. When the sludge is very rich, rough cloths rubbed with mercury, or even sheepskins, the lineal descendants of the Golden Fleece, may be used, 'Broad Tom,' _alias_ the 'Victoria Jenny Lind,' is made about half the length of its long brother: the upper end is only a foot wide, broadening out to three below.

'Tom' begat the sluice, which is of two kinds, natural and artificial. The former is a ditch cut in the floor, with a _talus_ of one to forty or fifty. The bottom, which would soon wear away, is revetted with rough planks and paved with hard stones, weighing ten to twenty pounds, the grain being placed vertically. With a full head of water 400 cubic yards a day can easily be washed. The gold, as usual, gravitates through the c.h.i.n.ks to the bottom, and finally is cradled or panned out. It is most efficiently treated when the sluice is long; it demands six times more water than the artificial article, but it wants less manual labour. This last property should recommend it to the Gold Coast. Here, I repeat, machinery must be used as much and manual labour as little as possible.

The artificial or portable box-sluice is a series of troughs each about twelve feet long, like the upper compartment of 'Long Tom.' They are made of half-inch boards, rough from the saw, the lower end being smaller to fit into its prolongation. Each compartment is provided with a loose metal bottom pierced with holes to admit the dust; the true bottom below it has cross-riffles, and above it are bars or gratings to catch the coa.r.s.er stones. These sluices are mounted on trestles, and the latter are disposed upon a slope determined by the quant.i.ty of water: the average fall or grade may be 1 to 50. In Australia four men filling a 'Long Tom,' or raised box-sluice, will remove and wash twenty-four cubic yards of ground per day. When the ore is fine, mercury may be dropped into the upper end of the sluice; and it picks up the particles, 'tailing,' as it goes, before the two metals have run far down. Both stop at the first riffle or resting-place.

The auriferous clays of the Gold Coast are thinly covered with humus, and are not buried, as in Australia, by ten to thirty feet of unproductive top-drift. The whole, therefore, can be run through the sluices before we begin mining the underlying strata. Washing will be easier during the Rains, when the dirt is looser; in the Dries hard and compact stuff must be loosened by the pick and spade or by blasting. There will not be much loss by float-gold, flour-gold, or paint-gold, the latter thus called because it is so fine as to resemble gilding. Spangles and specks are found; but the greater part of the dust is granular, increasing to 'shotty gold.' The natives divide the n.o.ble ore into 'dust-gold' and 'mountain-gold.' The latter would consist of nuggets, 'lobs,' or pepites, and of crystals varying in size from a pin's head to a pea. The form is a cube modified to an octahedron and a rhombic dodecahedron. These rich finds are usually the produce of pockets or 'jewellers' shops.' I am not aware if there be any truth in the rule generally accepted: 'The forms of gold are found to differ according to the nature of the underlying rock: if it is slate the grains are cubical; if granite they are flat plates and scales.'

And, lastly, the sluice begat the jet, or hydraulicking proper, which is at present the highest effort of placer-mining. We thus reverse the primitive process which carried the wash-dirt to the water; we now carry the water to the wash-dirt. In California I found the miners washing down loose sandstones and hillocks of clay, pa.s.sing the stuff through sluices, and making money when the gold averaged only 9_d_. and even 4_d_. to the ton. A man could work under favourable circ.u.mstances twenty to thirty tons a day. An Australian company, mentioned by Mr. R. Brough Smyth, with 200 inches of water, directed by ten hands, 'hydraulicked' in six days 224,000 cubic feet of dirt. The results greatly vary; in some places a man will remove 200 cubic yards a day, and in others only 50.

Hydraulic mining on the Gold Coast, owing to the conformation of the country, will be a far simpler and less expensive process than in California or Australia. In the latter water has first to be bought, and then to be brought in pipes, flumes, leats, or races from a considerable distance, sometimes extending over forty miles. It is necessary to make a reservoir for a fall. The water then rushes through the flexible hose, and is directed by a nozzle against the face of the excavation. The action is that of a fireman playing upon a burning house. Most works on mining insist upon those reservoirs, and never seem to think of washing from below by the force-pump.

I have shown that the surface of the lands adjoining the Ancobra is a series of hummocks, rises, and falls, sometimes, though rarely, reaching 200 feet; that water abounds, and that it is to be had gratis. In every bottom there is a drain, sometimes perennial, but more often a blind gully or creek, [Footnote: The gully feeds a 'creek,' the creek a river.] which runs only during the Rains, and in the Dries carries at most a succession of pools. Here Norton's Abyssinian tubes, sunk in the bed after it has been carefully worked by the steam-navvy for the rich alluvium underlying the surface, would act like pumps, and dams would form huge tanks. Nor would there be any difficulty in making reservoirs upon the ridge-tops, with launders, or gutters, to collect the rain. Thus work would continue throughout the year, and not be confined, as at present, to the dry season. A pressure of 100 to 200 lbs. per square foot can easily be obtained, and the force of the jet is so great that it will kill a man on the spot. The hose should be of heavy duck, double if necessary, rivetted and strengthened by metal bands or rings--in fact, the crinoline-hose of Australia. Leather would be better, but hard to repair in case of accidents by rats; guttapercha would be expensive, and perhaps thin metal tubes with flexible joints may serve best. The largest hose carried by iron-clads measures 19 to 20 inches in diameter, and is worked by 30 to 40 horse-power. Other vessels have a 15-inch hose worked by manual labour, fifty men changed every ten minutes, and will throw the jet over the royal yards of a first-cla.s.s man-of-war. The floating power-engines attached to the Dockyard reserves would represent the articles required.

With a diameter of from ten to fifteen inches, and a nozzle of three to four inches, a 'crinoline-hose' will throw a stream a hundred feet high when worked by the simplest steam-power process, and tear down a hill more rapidly than a thousand men with shovels. The cost of washing gravel, sand, and clay did not exceed in our colonies 1_d._ to 2_d._ per ton; and thus the working expenses were so small that 4_d._ worth of gold to the ton of soft stuff paid a fair profit. Lastly, there is little danger to the miner; and this is an important consideration.

It is well known that California was prepared for agriculture and viticulture by 'hydraulicking' and other mining operations. It will be the same with the Gold Coast, whose present condition is that of the Lincolnshire fens and the Batavian swamps in the days of the Romans. Let us only have a little patience, and with patience perseverance, which, 'dear my Lord, keeps honour bright.' The water-jet will soon clear away the bush, washing down the tallest trees; it will level the ground and will warp up the swamp till the surface a.s.sumes regular raised lines. We run no risk of covering the face of earth with unproductive clay. Here the ground is wanted only as a base for vegetation; sun and rain do all the rest. And thus we may hope that these luxuriant wastes will be turned into fields of bustling activity, and will tell the tale of Cameron and me to a late posterity.

But gold is not the only metal yielded by the Gold Coast. I have already alluded in the preceding pages to sundry silver-lodes said to have been worked by the old Hollanders. As is well known, there is no African gold without silver, and this fact renders the legend credible. Even in these dullest of dull days 63,337_l_. worth was the export of 1880. Iron is everywhere, the land is stained red with its oxide; and manganese with cobalt has been observed. I have mentioned that at Akankon my companion showed me a large vein of cinnabar. Copper occurs in small quant.i.ties with tin. This metal is found in large veins streaking the granite, according to M. Dahse, who gave me a fine specimen containing some ten and a half per cent. of metal. He has found as much as twelve per cent., when at home 2 to 2-1/2 per cent. pays. [Footnote: 'The present percentage of block-tin derived from all the tin-ore ... of Cornwall is estimated at 2 per cent., or nearly 45 lbs. to the ton of ore.'--Davies, p. 391.] The aspect of the land is diamantiferous; [Footnote: I hear with the greatest pleasure that a syndicate has been formed for working the diamond-diggings of Golconda, a measure advocated by me for many years. Suffice to say here that the Hindus rarely went below 60 feet, because they could not unwater the mine, and that the Brazilian finds his precious stones 280 feet below the surface. Moreover the Indian is the only true diamond: the Brazilian is a good and the Cape a bad natural imitation.] and it has been noticed that a crystal believed to be a diamond has been found in auriferous gravel. In these granitic, gneissose, and quartzose formations topazes, amethysts and sapphires, garnets and rubies, will probably occur, as in the similar rocks of the great Brazilian mining-grounds. The seed-pearl of the Coast-oyster may be developed into a tolerable likeness of the far-famed pear-shaped _Margarita_ of Arabian Katifah, which was bought by Tavernier for the sum, then enormous, of 110,000_l_.

Pearl-culture is an art now known even to the wild Arab fisherman of the far Midian sh.o.r.e. Lastly, the humble petroleum, precious as silver to the miner-world, has been found in the British Protectorate about New Town.

APPENDIX II.

PART I.

LIST OF BIRDS COLLECTED BY CAPTAIN BURTON AND COMMANDER CAMERON.

By R. BOWDLER SHARPE, F.L.S.

Vulturine Sea-eagle. Gypohierax angolensis.

Osprey. Pandion haliaetus.

Touracou. Corythaix persa.

Red-headed Hornbill. Buceros elatus.

Black Hornbill. Tockus semifasciatus.

Red-throated Bee-eater. Meropiscus gularis.

Blue-throated Roller with Eurystomus afer.

yellow bill.

Kingfisher with black and red bill. Halcyon senegalensis.

Small Woodp.e.c.k.e.r. Dendropicus lugubris.

Sun-bird. Anthothreptes rectirostris.

Grey Flycatcher. (3 spec). Muscicapa lugens.

Dull olive-green Flycatcher with Hylia prasina.

pale eyebrow. 19.

Common Swallow. 33. Hirundo rustica.

Black Swallow with white throat. 30. Waldenia nigrita.

Grey-headed Wagtail. 22. Motacilla flava.

Black and chestnut Weaver-bird. 23. Hyphantornis castaneofuscas.

Turtle-dove. 15 Turtur semitorquatus.

Whimbrel. 5 Numenius phaeopus.

Grey Plover. 13 Squatarola helvetica.

Common Sandpiper. 18 Tringoides hypoleucus.

Spur-winged Plover. 11 Lobivanellus albiceps.

Green Heron. 7 Butoides atricapilla.

PART II.

LIST OF PLANTS COLLECTED ON THE GOLD COAST BY CAPTAIN BURTON AND COMMANDER CAMERON, R.N.

(FURNISHED BY PROFESSOR OLIVER.)

_A considerable number of specimens either in fruit only or fragmentary were not identifiable._

Oncoba echinata, Oliv.

Hibiscus tiliaceus, L.

" Abelmoschus, L, Glyphaea grewioides, Hk. f.

Scaphopetalum sp. ? fruit.

Gomphia reticulata, P. de B.

" Vogelii, Hk. f, " aff. G. Mannii, Oliv. an sp. nov. ?

Bersama? sp. an B. maxima? _fruit only_ Olaoinea? an Alsodeiopsis? _fruit only_ Hippocratea macrophylla, V.

Leea sambucina, W.

Paullinia pinnata, L.

? Eriocoslum sp. (fruiting specimen).

Cnestis ferruginea, DC.

Pterocarpus esculentus, Sch.

Baphia nitida, Afz, Lonchocarpus sp.?

Drepanocarpus lunatus, Mey.

Phaseolus lunatus? _imperfect_ Dialium guineense, W, Berlinia an B. ac.u.minata? var. (2 forms.) Berlinia (same?) in fruit.

Pentaclethramacrophylla, Bth.

Combretum racemosum, P. de B.?

Combretum comosum, Don.

Lagunoularia racemosa, Gaertn.

Begonia sp. flowerless.

Modecca sp. nov. ? flowerless.

Sesuvium Portulacastrum? barren.

Tristemma Schumacheri, G. and P.