Rock Testing Procedure
Design engineers involved with mine or tunnel construction require knowledge of rock behavior in order to assure economic excavation of rock and stability of underground openings. For many applications, the behavior of a rock is determined from an engineering approach involving rather empirical experiments. A greater emphasis is now being placed on the use of […]
Zinc Electrowinning & Impurities
In the commercial electrowinning of zinc, zinc oxide is leached from the roasted calcine with an aqueous acid sulfate electrolyte. The zinc-rich solution is purified and then passed into an electrolytic cell where a fraction of the metal is cathodically deposited. The spent electrolyte is pumped from the cell to readjust the zinc concentration by […]
Hydrocyclone for Coal-Washing Equipment
The profitable operation of a coal preparation plant under today’s stringent product standards and ever-rising labor, material, energy, and equipment costs requires that the preparation engineer continually strive for maximum recovery of salable coal. Good performance data are a prerequisite to the design of a new plant or to the expansion of existing facilities, and […]
Zirconium Oxide Molds for Molybdenum
One of the goals is to minimize the requirements for critical and strategic mineral commodities through conservation and substitution. As a part of this effort, the Bureau conducted research to develop molybdenum as a potential substitute for alloys containing the critical and strategic metals nickel, chromium, or cobalt. As expressed in Iron Age, this Nation […]
Radial-Axial Loading Splitting Tool
As a part of the Bureau of Mines research program to develop new mining methods for underground bedded deposits, a rock splitting tool capable of applying both radial and axial forces is being investigated as a primary excavation tool. From the long-known hammer-driven wedge and ice expansion methods of propagating existing cracks in rock, mechanical […]
How to Recover Chromium Nickel Cobalt Laterite
Chromium is essential to modern industry, and there are few acceptable substitutes for most of its metallurgical and chemical applications. In 1979 the United States consumed 610,000 tons of chromium, of which about 10 pct was supplied from secondary sources from within the country; the remainder was imported. Annual consumption is projected to grow to […]
Gas Fired Iron Ore Pelletizing Kiln
The iron oxide pelletizing industry is very energy intensive and relies heavily on natural gas to fire pellet-indurating furnaces. Approximately 75 million long tons of iron oxide pellets are produced in the United States each year, requiring a fuel input of about 55 billion ft³ of natural gas. During the past several years the industry […]
Effects of Velocity and Orientation on HydroCyclone
The 10-mm Dorr-Oliver cyclone is used for dust compliance sampling, which includes both stationary and personal sampling. The cyclone classifies “respirable” size particles, which are particles that reach the alveolar regions of the lungs, usually considered to have aerodynamic diameters (AED) of 10 µm or less. Although there are believed to be no instruments that […]
How to Remove Mercury from Flotation Concentrate by Leaching & Electrolysis
Primary mercury metal is produced commercially by heating mercury sulfide concentrate in furnaces to vaporize mercury metal, which is cooled and recovered in a condensing system. Potential health and safety problems exist because mercury vapors can escape from the furnace and condenser. The Bureau of Mines and McDermitt Mine, operated by Placer Amex Inc., the […]
How to Recover Barite from Waste Pond Materials
A major goal of the Bureau of Mines is resource conservation, which includes (1) maximizing mineral recovery from domestic resources and (2) recovering mineral values currently lost in scrap and waste materials. To help meet this goal, the Bureau of Mines has been investigating the recovery of various potentially valuable minerals from mineral- processing wastes. […]