CURING COPPER PLATES.

Westport Times, Volume III, Issue 444, 2 January 1869, Page 2

CURING COPPER PLATES.

(FKOM OUE CHARLESTON COBRESPONDENT.) I have made enquiries respecting the new method of curing copper plates recently referred to in your columns. I have seen the plate placed as an experiment on the tables of the Southern Cross Gold Mining Company. The manager, as well as other pr.i--tieal miners, highly approved o\' this plate. No verdigris was visible on the plate, although it had been placed at the tail end of the tables for a period of nine days, no gold coming on to it during that time. The discoverer (Dr. Bakers) will guarantee to cure ordinary copp?r plates in three to four hours, to the perfect satisfaction of any miners requiring them. This plate has been subjected to a very severe test, because it has been placed where there has been no gold coming down, and where the sand comes on to it with a drop of inches. Although the force of the falling sand has removed the quieksilver from the head of the plate, yet the copper plate is not visible, the enamel not being cut through. The cost of curing under the old process would be—First the amount of gold that remains on the plate. This you can safely reckon at lgr to to the square inch. This in a plate 4 + 2, equal to 8 square fteet, would give from 2 oz 8 dwt to 3 oz. 12 dwts. The value of this at £3 16s 9d per oz. would amount to from £9 4s 2d to £l3 16s 3d. Secondly the value of the gold that passes over the plate. This would be at least an equal amount. Thirdly, the amount of wages paid until the plates are cured. To reduce this to figures, reckon 1 gr. to the square inch to cure the plate. We have on a plate, 4x12, 2oz 8 dwts. An equal quantity passing over gives us 4 oz. 16 dwts., value, £lB 8s 4d, for each plate. If eight plates are used this will give £147 6s Bd, allowing the plates to cure themselves in three weeks. The claim being moderately good, say eight men employed on the claim—wages at £4 10s per week. This is equal to £IOB. This, added to the cost of the gold will amount to £255 6s Bd, at the lowest estimate, or an average of nearly £32 per plate. The cost of curing under the new process would be £lO per plate, a fact that speaks volumes in favor of the new process, as it is less than a third of the cost of of the ordinary procoss. We understand the discoverer, Dr Dakers, will guarantee a perfect cure or make no charge, and can also supply cured plates at a few hours' notice. No acids or cyanide of potassium are used in this process or preparing the plates by this process, neither can the copper he injured in any way by it; the enamel being first prepared, and then carefully laid on in such a way that nothing short of cutting into the copper can remove it.