CORRESPONDENCE

Evening Post, Issue 149, 20 December 1935, Page 6

CORRESPONDENCE

"GOLD AND ITS COSTS"

(To the Editor.)

Sir, —It was with great interest indeed that I read your leading article "Gold and its Costs'," in the "Evening Post" dated December 11, especially with regard to the question, "Cannot gold mining be so conducted ■ that money shall not be spent uselessly?" The remarks re drilling and the valuation of alluvial deposits are also noted, especially the part mentioning that the boring result has not proved reliable in all cases in New Zealand.

I feel quite confident that as in the past, the .future gold won in this country will be largely produced by alluvial workings, and while the most efficient method of .turning- over alluvial drift in quantity and with reasonable percentage recovery is by means: of up-to-date bucket dredges, the fact remains that modern buckets dredges, which are now designed to operate at a depth of 120 feet if necessary, and to dig up t0.300J000 cubic yards of material per month, are expensive machines, and to justify the cost of their installation- the value of the ground and the cubic yardage available to decide the life of the property must be known "and checked" within a reasonable degree of ■accuracy; ■ After many years experience in Siam and the Federated Malay States in connection with the Tin Dredging industry and valuation of dredging'properties, I feel qualified to, pass an opinion that I have held for the past six years in connection with the subject matter under discussion. <

To digress a little, we will assume that any average man of our acquaintance has some minor disorder necessitating a small operation; assume that' friend "A," who" has studied medicine for a few years, but is lacking in full training-and experience, offers to "have ago at it," while. "Bl^ is a fully-qualified medical practitioner and has performed a similar operation scores of times and wiirrequire a fee. of twenty guineas. MT ° whom will our .sick friend turn, "A" or 'B"? I am very certain that 999 men .out of a thousand would not hesitate; "B" would do the.work and receive the remuneration required for the work. If then, this is the attitudetowards our health, the maximum of safety first" proving desirable; would it not be in order to be as conservative with the money we invest in mining enterprise?

On looking back I find I cannot recall a case in the East where a property had been drilled by a qualified and experienced .mining engineer, and dredging results did not approximately equal, and in odd cases, exceed the value shown on the boring plan,; But even with this efficient state of affairs, in nearly all cases check boring was performed by an,independent engineer. Where the price per bz (in the case of gold) or per lb (in the case of tin) is calculated in conjunction with the known yardage turnover of the dredge or plant the actual profit per month or per year and the return on the capital invested can be known in advance within very fine limits of accuracy. Dredging and alluvial mining is unlike lode mining, where what lays ahead of pick point is largely a matter of conjecture.- In an' alluvial deposit which has been bored and checked by competent and experienced engineers the results are certain^ and the whole business savours more of industry" ( than "speculation." ' = This country has many excellent schools of mines, that well-known institution, the Otago School'of Mines, has produced men who are occupying the front, rank of their profession In the world's mining 'fields, but I have seen very few .boring reports signed by these men or "their professional brothers of similar institutions. To me the answer to the plea for greater reliability in boring results seems obvious—all boring and check boring should be carefully supervised by a qualified mining engineer,; a graduate of a mining school or university with some years of practical alluvial experience, and then "dud" flotations would become nearly as extinct as the "Dodo."—l am,, etc; F-C. GRUBB, A.Z.S.M., Assoc. instMM.