Show ZINC DUST AND ZINC shavings SHAVING 9 the following communication from th the merrill metallurgical company engineers of san francisco has just been received by the mining review the article to which it refers was sent in by a correspondent in california and this letter from mr mills mill gives the other side of the question editor the mining review salt lake city utah dear sir on page 31 of your issue of july appears an article commenting upon advantages of zinc shavings precipe preci pi tation as compared with the results obtained with zinc dust and closing with a statement of the present patent situation which can hardly fail to leave an erroneous impression in the minds of many of your readers we therefore ask that you give the same publicity to the following facts which constitute the other side of the case the original zinc dust process as installed and operated at the de lamar mill at mercur utah never was a success and was abandoned in favor of other methods this failure was due to lack of precautions later developed and embodied in the merrill patents the basic one of which is no in which are clearly described the advantages of avoiding oxidation and of maintaining agitation without contact with air these patents are still in force and the present almost universal use of zinc dust for precipitating cyanide solutions is based upon licenses issued under these patents yours very truly MERRILL metallurgical CO by louis D mills |