Water Filtration by MgO Magnesium Oxide
Suspended solids are a common impurity in mine water. Mines rely mainly on flocculation and settling for solid removal, but this can be unreliable owing to seasonal variation in water temperature, runoff, and changes in the character of ores being mined. Filtration is often needed to provide sufficiently pure water to meet mineral processing requirements […]
Tailings Pond Seepage Control
During operation of tailings impoundments, water is lost through decanting, evaporation and seepage. Techniques have been developed to regulate or control each of these components. Collectively implemented, these techniques form the basis of tailings impoundment management. Regulation of the rate and level of decanting influences the size of a free water pond, and, thereby, the […]
Tailings Belt Filter Press
Crushed ore is reclaimed in a 3.7 m (12′) diameter tunnel with, two variable speed slot feeders. Mill feed is conveyed to a 3.7 m x 1.2 m (12′ x 4′) 250 hp semi-autogenous (SAG) mill. Lime is screw fed onto the conveyor inside the reclaim tunnel. The SAG mill discharge enters a common sump shared […]
Caro’s Acid – Cyanide Detoxification Process
This powerful CN- detoxification agent is prepared by mixing concentrated sulfuric acid and concentrated H2O2. H2O2 + H2SO4 → H2SO5 + H2O The formation of Caro’s acid is instantaneous and is accompanied by the evolution of heat, primarily due to the heat of dilution of sulfuric acid. Because of it’s tendency to decompose to oxygen and […]
In Situ Mining Well Construction
The objective for this U.S. Bureau of Mines (USBM) research is to evaluate construction and completion methods and costs for vertical in situ copper mining wells to depths of up to 1100 m (3600 ft). Appropriate construction materials and costs have been determined for well equipment, casing, drilling, cementing, and completion. A “deep” single ore-zone […]
Using Wetlands for the Control of Acid Mine Drainage
Metal Removal Processes of Wetlands A wetland environment can remove metals from influent waters in a variety of ways. As chemical oxidation takes place, oxides and hydroxides of iron can be expected to precipitate from surface flow, resulting in the characteristic yellow sediment in mine drainage known as “yellow boy”. These precipitates coat the surfaces […]
Mine Waste Tailings Beaching
The Bureau of Mines surveyed waste disposal sites at 18 metal and non-metal mines and conducted laboratory and full-scale field tests to determine the effects of tailings deposition techniques on physical properties of tailings pond beaches. Survey data included measurements of beach slopes, descriptions of deposition techniques, and measurements of beach physical properties taken at […]
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 […]
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 […]
Water Hyacinth Roots & Water Purification
In the environmental treatment field, if the water hyacinth root is to be considered as a viable treatment method for metal-bearing waste streams, sorption data and the corresponding isotherm parameters must be generated and made available to the scientific and engineering communities. The maximum sorption uptake value is an important feature of the sorbent characterizing […]