NOTES ON GOLD-MINING.

Cromwell Argus, Volume III, Issue 122, 12 March 1872, Page 6

NOTES ON GOLD-MINING.

BY VIATOR. *■ The encouraging reception my last commu. nication on the above subject received at your hands, emboldens me to continue my humble efforts. But be it understood that [ am not a scientific man (except in a very small way), and not wishing to get beyond my depth, I will refrain generally from the use of geological terms, having a tendency to dislocation of the jawbone. In imparting my experiences, I will endeavour to keep to those terms in common use among miners, as I well know that the most abstruse and highly embellished descriptions are those least appreciated by that section of the com. munity these notes are intended to instruct. I left off at chemistry as an adjunct to the extraction of the ore from its matrix, when the same is taken from deep levels; —and this brings to my mind one fact which may have escaped the notice of most quartzminers, and that is, that the aid of this profound science is needed by the manipulator in Otago from the present surface downwards. Dr Hector, the Government Geologist, has told us that at least COO feet of the original formation of most of the auriferous districts in the Province, has been worn away by subsequent disintegrations and abrasions, by ocean currents and atmospheric influences, resulting in the debris which we find in the gullies and lower adjacent lands, In many mines in Victoria—from whence out experience in the art of gold-saving is mostly drawn —the chemical difficulties are encountered before the depth of 000 feet is reached in the lode. Combine this fact with the well- | known differences in the superficial strata of the two countries, and I think it may reason! ably be conceded that, as Nature's laws adini:. of no variation, the outer terrestrial coating of Victoria is thicker to the extent of 300 tc | 500 feet, having suffered so much less degra-j j dation than Otago. Therefore we, on firs: j opening a quartz vein, have all those difneulj I ties and hindrances to amalgamation to en- ! counter which are now engaging the attention] of eminently practical men in the older goldi producing countries. How far the presen; ! available talent in quartz manipulation i; able to cope with the difficulties attending the extraction of all the precious metal, the mournful list of defunct and moribund com-. panics furnishes a lamentable example. However, cxperieatia docet, and we may hope ii : time to note an improvement in this parti I cular. 1 intend, in a future article, to devote a chapter to the "how and wherefore" o: | such a desideratum.—To resume.

There is one condition at which quart lodes in all countries arrive as greater depth are reached—viz., they begin to look blue;I do not mean the cerulean appearance con sequent on no dividends, but literally bliii in colour : the surrounding strata are bluethe quartz white, with steely blue intersectin: veins. Such an appearance, as Dr Hecto: again remarks, is an invariable indication o a " deep reef." Now, as the earth's crustii assumed to be about 200 miles thick, and fchi gold and silica having been ejected througl that space, we may suppose that, owing t gravitation, the fissures or outlets still retai: imprisoned quart;: and gold to at least a cor. siderable portion of the distance ; therefore any such contingency as the exhaustion of: reef is, I think, improbable. I have onli noticed one reef, so far, in Otago partakiri: of the " true blue" or deep character, an that was at the Ida Valley Company's mint Rough Ridge. The indications of profundit were exhibited at the mouth of the mail level, in a gully where the lode was tin opened, and was continued down to a depf: of 180 feet. Farther up the hill, the veil assumed a ferruginous and mullocky appear ance (" breccia" in geology. lam indebte. to Mr V. Pykc for the term). All the ree: on Bcndigo and the Carriek are of this lattc description ; so if any doubt exists as to the: continuation downwards, let me quiet it b; the assurance that 250 or 300 feet will ha* to bo pierced in either place before the surface indications of the Ida Valley reef »" reached, for, as I before remarked, ft "blue" condition is inevitable.

Among the " intelligent body of minors'H as our .Representatives are pleased to call when wishing to "woo our sweet voices "* there must be some who have " taken notes] during their experience on the gold-fields! I should like very much to hear how the'] ideas travel with mine on the subject-matit; in hand. The importance of the object sougt] would excuse the advent of two (or mow! " Richmonds in the field." Bendigo, March «>.