Show MISTAKES IN ASSAYING in all mining camps there is more or less gambling by the prospector leaser or mine owner in regard to assaying and the results returned by assayers particularly is this true in new camps and it is the purpose of this article to show the causes of a wide variance in the returns of assayers the greatest evil the prospector encounters is incompetent or wilfully dishonest men who do not even try to do their best or fairly good men who are so handicapped by poor appliances they cant do good work say J T elkins in the goldfield news the assay sample should receive the greatest care from the time it passes tai ses into the hands of the assayer cleanliness and carefulness in mixing the sample after crushing and careful pulping are absolutely necessary into a custom office comes ores of all grades and there is the constant danger of salting subsequent samples after pulverizing ver izing a high grade ore the conscientious man keeps a list of the order in which the various samples are pulped gulped and is therefore able to check up any salt occurring in the bucking room the pulp passes to the balances to be weighed in and must receive a thorough mixing before the assay charge is taken out after this stage has been passed average assayer through incompetency wilful negligence pays little or no attention attenni or 01 on to the assays essays except to melt them in haphazard way and cupel the lead button butta any resulting from the fusion at any old heat 3 the losses occurring during the fusion fusi may be very great in some instances ex peri ments have shown a loss of gold vai vary y ing from three per cent to twenty per cent and of silver varying from seven even per cent to thirty per cent the fusion to be as nearly accurate as possible is best performed in a muffle furnace where the heat is even and at all times under the control of the operator fusion must take place in all parts of the crucible simultaneously this is IF obviously an impossibility in the gasoline furnace too great a starting heat causes violent ebullition of the melting charge and values are thrown out of the crucible and in case of rich samples being next to low grade fusions there i a great danger of salting A transference of values from one crucible to another may be accomplished with the tongs used in placing the charges into the furnace the finishing heat of a fusion is also a very important point or the values retained in the slag will be enormous the writer has experimented with highly gold and silver ores and found that the slag retained from iya to 3 per cent of the gold and as high as 12 per cent of the silver values this was corrected by using a more fluid slag and a higher finishing temperature in removing the slag from the lead buttons careful attention will imperfect fusion or poor fluxing flexing flu xing and such lead buttons should be discarded and the assay rerun or the losses will be large during the which is the most delicate part of the assay the losses during are caused by too great a degree of heat during the operation era tion poor capels or fuel lead buttons many assayers claim that heat does not affect gold true gold does not volatilize itself at a possible assay furnace heat but the too rapid volatilization of the lead will carry off some gold values and a large amount of silver the intense heat also assists the impurities in the lead button to carry the gold and silver into the cupel from experiments performed by fuman collie wood T kirk ross the author and others it has been found that the materials of tha ta used in and the construction cupel has a great influence over the result resu the blue ash should be of the very w best made and a grade and each cupel carefully will tested or the utmost care in cu chow show a loss of from 5 to 30 per cent ol of the values of the e 01 even with the best capels s some ome affect the common elements of ores largely I 1 re rem results unless they are thoroughly before passing the button to the cupel cup anost the ane w of these tellurium is probably disconcerting to the inexperienced man as the losses will at times reach as high as T per cent on a very rich ore bismuth 1 is the next hardest element with which to deal as it has a very large capacity for carrying gold and silver values into the cupel experiments have shown a loss as high as 21 per cent of the gold and per cent loss of the silver arsenic anti mony copper zinc and sulphur all have a tendency toward lowering the results even proof gold with chemically pure lead may show a big loss during su if the temperature be too high and during this stage the operator should give the capella tion his careful and constant attention and i he should have a furnace over the heat of which he has absolute control as a varia i tion of comparatively few degrees has a marked effect upon the results it is ob an impossibility for the assayer to do good work cu in a combination furnace at the same time he is running melts in the crucible chamber as either one operation or the other must be slighted in looking for a man to do your work first look for the competent conscientious assayer who knows how and is not a mere machine treating all ores alike be certain he will give your sample the same careful attention he gives to those of his best customers see that your assayer has proper appliances ances and is careful in the bucking room that he has a furnace capable of doln boins the best work that his balances are such as to give accurate results there are in every camp several good men with good appliances ances and if you are spending your money and expecting good results these are ara the men you should patronize |