Associated Minerals: Placer gold invariably is accompanied by other heavy minerals, which comprise the black, white, or yellow concentrates found in the sluice box when cleaning up. Table 3 lists these minerals roughly in the order of their commonness. Some of the characteristics noted under Remarks apply chiefly to the minerals as they are found in … Read more
The past decade has provided a wealth of practical experience with longwall pillar design. Design formulas developed specifically for longwalls have proven their value in numerous applications. Analytic methods, including numerical models, have also made important contributions. These advances have been based on basic research into abutment loads, coal pillar mechanics, and the interaction between … Read more
The US Bureau of Mines is conducting core leaching experiments with sulfuric acid on oxide copper ores from the Cyprus Casa Grande and Asarco-Freeport Santa Cruz deposit in Arizona to further the understanding of the leaching process in supergene copper ores as it relates to in situ mining. Leach solutions from atacamite mineralization contained 5 … Read more
Placer Prospecting Practice Prospecting methods have been developed and well established within the last few years. Sinking pits and shafts generally gives good results, but this work is usually expensive and generally slow and troublesome, owing to the presence of water in most placer ground or to the necessity of timbering the shafts. With the … Read more
Instructions on staking claims and filing for patents can be obtained from the U.S. Bureau of Land Management. In addition to Federal regulations, individual States also have certain requirements pertaining to the location of claims on public lands. Information on these requirements is available from the State agency that deals with mining. Claims for mining … Read more
Placer gold has tantalized many a person who has tried his luck and skill in the hope of striking it rich. Separating gold from embedded materials is basically simple, and can be done effectively on nearly any scale, depending upon the deposit and the capital available for investment. The final product is consistently in demand … Read more
In diamond-drill work, a true sample consists of all the material cut by the bit—both core and cuttings. As the recovery of this sample is the object of diamond drilling, the utmost care should be taken to secure it. Speed of drilling and low costs are of little value if an inaccurate sample is obtained. … Read more
A vein may be defined as an aggregation of mineral matter, more or less tabular or lenticular in form, which was deposited from solution and is of later origin than the inclosing rock. This definition differs from the one found in many textbooks in that no assumption is made as to the origin of the space … Read more
I consider the lead and zinc deposits of the Mississippi Valley to be the result of descending waters. There are many features that we have not determined and yet when you see the general field relations, it seems to me that the cause and effect can be well explained by descending circulation. In the Joplin-Miami … Read more
The exploration of deposits of the metals will never become an exact science. There will always be an element of uncertainty in prospecting and developing mines. In countries where the surface has been closely scrutinized, most of the deposits whose outcrops contain valuable metals have probably been discovered. Many metalliferous deposits, however, are normally so … Read more