Environmental Auditing Procedures in Mining
Environmental audits can serve many purposes. One way in which an audit may be used is to assess an operating company’s compliance with environmental laws while the mine is in operation. Information derived from an audit of this type can guide management toward making immediate adjustments to correct procedural problems before they create major environmental […]
Ultimate Pit Limit Design
In open pit mine planning, the design of the most profitable ultimate pit limit is a prerequisite to developing a feasible mining sequence. Presently, the design of an ultimate pit is achieved through a computer program in most of the mining companies. 3-D block model is commonly applied to represent geologic and economic information of […]
How Temperature Affect Grinding Efficiency
The effects of temperature on autogenous grinding can be immediately divided into rheological effects and mechanical effects. The rheological effects are a result of the substantial increase in the viscosity of water as the freezing point is approached. The change in apparent slurry viscosity which results from changing temperature is shown in Figure 1. As […]
Compacted Clay Liners
Soils used to construct compacted permeability barriers such as liners for solid and liquid waste landfills and lagoons must be carefully evaluated and designed to maintain their integrity in preventing seepage of pollutants off site. The practice of using any on-site soil without testing its hydraulic and flexural properties is dangerous. Silts and fine sandy […]
Sulfate Ion & Anionic Surfactants
The U.S. Bureau of Mines is investigating surfactants added to water sprays to enhance the control of dust during coal mining operations. The objective of the present work was to establish the general applicability of adding sulfate ion to anionic surfactant solutions in order to improve wetting action. This was pursued through laboratory wettability testing […]
Pressure Leaching of Galena to Recover Lead by Electrowinning
As part of the U.S. Bureau of Mines program to improve base metal leach systems, pressure leaching of galena (PbS) concentrates in fluosilicic acid (H2SiF6) solution was investigated. Lead extraction was 93 pct when PbS was pressure leached in H2SiF6 at 95° C with 200-psig O2 pressure for 40 min, using ferric nitrate [Fe(NO3)3] as […]
Electric Arc Furnace
The U.S. Bureau of Mines is conducting an ongoing research project to better understand the phenomena involved within electric arcs utilized in electric furnace steelmaking. With a better understanding of the physical and electrical characteristics involved, dynamic or predictive control of electric arc furnaces may be possible. A mathematical model is presented, but not solved, […]
Froth Flotation Bubble Collision
Collision efficiencies have been calculated using a two-particle model in a strong force field. The nondimensional equations of motion have been solved numerically, showing the effects of changes in K, W, and particle-to-bubble radius ratio R for both viscous and potential flow. The results of Flint and Howarth have been extended to include higher values […]
Electrorefining Calcium Metal Electrowinning
The U.S. Bureau of Mines developed an alternative electrochemical process for the production of calcium metal. The current industrial practice is costly, complex, and inefficient. The Bureau method involved electrowinning of a calcium-tin alloy followed by electrorefining to produce calcium metal. In the electrowinning cell, CaCl2 was fed to a KCl2-CaCl2 electrolyte. The calcium was […]
Column Flotation Testing Better & Improved Recovery
We investigated column flotation for recovery of a high-grade fluorite (CaF2) concentrate and byproduct concentrates from the Fish Creek fluorite deposit in Eureka County, NV. The recovery scheme consisted of (1) grinding the ore to minus 48 mesh, (2) fluorite rougher and cleaner flotation, (3) desliming the rougher fluorite flotation tailings at 20 µm, (4) […]