From the viewpoint of mineral economics, the ultimate and significant production cost is that per unit of metal produced rather than the cost per ton of ore treated. This viewpoint is natural to processors of ores whose final product is refined or unrefined metal, whether they be companies engaged solely in smelting, or integrated companies … Read more
With the exception of gold, metal prices are subject to frequent fluctuation, resulting in corresponding variations in the value of their ores. Metal prices are quoted periodically in technical and trade journals and average yearly prices in the principal markets are discussed in the Minerals Yearbook, published annually by the Bureau of Mines. From time … Read more
Engineering valuations of raining properties are made for a number of purposes, principally the following: For purposes of purchase or sale on behalf of prospective buyers or vendors. For purposes of financing by bond issues or sales of stock. As a basis for taxation. In connection with trespass or damage suits. Theoretically the value of … Read more
Lead and Zinc Ores Minerals of lead and zinc commonly are rather closely associated in nature; zinc-free lead ores and lead-free zinc ores are exceptional rather than common, although there are such. Lead and zinc ores usually contain some silver, but those of the Mississippi Valley region are silver-free. Indeed, lead-zinc ores often are commercially … Read more
When most people think of shovels they think about the type of shovel used for metal detecting and general usage but since late in the last century, power shovels and draglines for digging and loading and locomotives and cars for hauling from the pit have been in general use at most large-scale open-pit operations. Starting … Read more
The four major steps in the production of marketable copper are mining, concentrating, smelting, and refining. In a few instances, however, leaching takes the place of concentrating, smelting, and refining. At present, although considerable leaching and direct-smelting ores are produced, the bulk of the copper ore mined is concentrated. The milling of copper ores as … Read more
In this bulletin the subject of ore dressing is approached from the economic rather than from the technological standpoint, and the supporting data have been compiled with a view to their bearing upon the economic exploitation of ore deposits. Results obtained are stressed rather than the details of processes and the physics and chemistry involved. … Read more
Open-pit mining methods are applicable to mining ore deposits that apex at or near the surface. If the deposit apexes below the surface, the overburden and barren capping overlying the ore must be removed in advance of open-pit mining. The removal of this material is known as stripping. The stripping-pit limits must be extended beyond … Read more
The low cost of mining was the principal consideration, since, with mercury’s price per pound, the total gross value of the ore did not exceed too much per ton. Square setting and filling was out of the question, so various attempts with cheap methods were made, among them a shrinkage system. None gave satisfaction on account … Read more
Stoping cost is one of the largest of the items comprising the total cost of producing ore. The cost per ton of ore mined is important but may be overemphasized if the more important cost, that per unit of metal recovered, is thereby overlooked. A given stoping method may give a low cost per ton … Read more