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Mill #4 processes mildly refractory ore from Carlin Trend deposits. Diagnostic analysis of plant operating data was used to generate a mathematical model containing the key parameters influencing the gold recovery. The model was used to direct modifications to plant operating practice. The cyanide dosing strategy was changed to reduce preg-rob gold masses and cut reagent consumption A finer grind was achieved without capital investment. The density in CIL was lowered, and tighter control was exercised over plant throughput. These changes resulted in a recovery increase of at least 2%, worth $111,000/month at $300/oz, and concomitant reagent cost savings of $55,000/month.

Jan 1, 1999

By J. P. Earnhardt

Recycling of such municipal solid wastes as glass containers, metal cans, and newspapers has received increasing attention recently. However, municipal solid wastes account for only 1% of the total solid waste stream in the United States. The remainder includes hazardous and non-hazardous industrial wastes. Generators of industrial wastes are facing higher landfill costs. Future liability potential, and public image concerns which are forcing them to seek innovative and often profitable solutions to minimize, reuse, and recycle their waste streams. Opportunities for the mining industry in industrial recycling include recovery of mining wastes and by-products, and utilization of mineral products for treating waste streams.

Jan 1, 1993

By R. G. Reddy

Solid state reduction of roast movat chromite ore with carbon was carried out as a function of C/FeO ratio and temperature in the range 800°C to 900°C by thermogravimetry analysis (TGA). A two stage mechanism, (1) the reduction of FeO present in Roast Movat with carbon monoxide; and (2) the regeneration of CO by the oxidation of carbon with CO2 was proposed. The rate controlling step is the carbon oxidation reaction. A kinetic equation, that of random nucleation, was proposed. The activation energy for the reduction was determined to be 55800 J/mole and is compared to those activation energies determined for other chromite ores.

Jan 1, 1998

By H. K. Lin

Elemental sulfur is founded to be the predominant sulfur-containing species in a leaching residue resulting from ferric chloride leaching, under given conditions, of a chalcopyrite concentrate. The mineralogical study of the leaching residue which consists of 52% elemental sulfur reveals that the sulfur formed at the end of leaching process is in the form of discrete crystal rather than coating film. Flotation has been applied to recover the sulfur successfully using xanthate as a collector. Dispersants arc needed to prevent the mechanical entrapment of silicate and quartz by sulfur. Very high recovery of sulfur with satisfactory grades can be achieved with a relatively simple notation scheme.

Jan 1, 1991

By X. P. Zheng

Barium fluorphlogopites were synthesized in the laboratory in order to investigate the effects of composition and crystal parameters on surface properties and floatability. The negative surface charge of mica is determined by the barium content, the crystal cell volume, the distance between layer structure and the Ba-O bond length. The higher barium content, the larger the cell volume and distance between the layer structure and the longer the Ba-O bond, the more negatively charged the surface is and hence the more easily adsorbed to cationic collectors. When an anionic collector (sodium oleate) is used, barium oleate forms on the mica surface and hence chemical adsorption occurs.

Jan 1, 1993

By T. Guler

Turkey has important celestite reserves in Sivas. These reserves have gypsum and/or calcite as gangue minerals. Celestite-calcite ore cannot be concentrated by gravity methods due to the low efficiency of gravity methods in fine sizes. Research was tried to concentrate celestite to a market grade by flotation. Parameters such as pH, particle size, dosage and types of collector and depressant were examined. Cyanamid A-845 and Na-oleate combination as collector, sodium silicate as depressant, and Aerofroth-65 as frother were found as the optimum flotation reagents. By applying 3-stage cleaning, a concentrate assaying 95,34 % SrS04 was obtained with 84,93 % recovery.

Jan 1, 1999

By J. C. Cawley

Improvements in today's maintenance practices are mandatory as more complex and productive machines evolve in the mining industry. By keeping machine reliability high, through improved maintenance procedures, overall mining costs can be reduced. The Bureau of Mines is investigating diagnostic maintenance systems for underground mining machinery. A hydraulic expert diagnostic system and an electric motor predictive diagnostic system have been designed and installed on a Joy 16CM continuous miner. An electrical diagnostic system has been designed and installed on a Joy 14CM continuous miner. Each system is functionally described and the relative merits of expert diagnostic systems versus algorithmic diagnostic systems are discussed.

Jan 1, 1991

By H. R. Manouchehri

The responses of calcite, feldspar, and quartz minerals In a laboratory free fall electrostatic separator, before and after tribocharging with stainless steel, PVC, and copper plates, have been investigated. The effect of H3BO3 and BaCl2 chemicals pre-treatment on the electrical properties of the minerals is examined. The changes in the electrical properties are discussed with the determined charge, dielectric constant, and electrical conductivity of the mineral samples. Electrical properties of the minerals and their responses to the electrical field during separation, after tribocharging and chemical pre-treatment, are explored for the need to characterize the electrical behaviour of the minerals.

Jan 1, 1998

By John P. Hunt

Early disseminated copper mineralization at Quebrada Blanca, Chile, accompanied 38 million year old quartz monzonite stocks and dikes. Early mineralization was followed by hydrothermal mineralization, mineralized breccias, and post-mineral faulting. After supergene leaching and enrichment, Quebrada Blanca was buried under late Tertiary gravels, and then partially re- exposed in Quaternary time. Based on work to date the orebody appears to contain more than one hundred million tons of plus one percent secondarily enriched copper ore, overlying several hundred million tons of protore averaging more than 0.5% copper. A source of industrial water appears to have been located. Pilot scale metallurgical tests, mine planning, and feasibility studies are in progress.

Jan 1, 1981

By Roger K. McLimans

Sphalerite in the ores is multi-banded. Based on color and textures, bands in samples separated by a few kilometers may be correlated. Darkness of color is directly related to iron content. Isotopic and fluid inclusion data indicate that temperatures of ore deposition were 225°C-50°C. The agreement between these two sets of data suggests that chemical and isotopic equilibrium were established. The salt content and hydrogen and oxygen isotopic compositions are similar to present-day values of oil field brines suggesting a similar mode of origin. Ore transport and deposition are not adequately explained by either chloride or bisulfide complexing. Necessarily, other mechanisms were involved.

Jan 1, 1979

By Carl L. Morris

This short dissertation concerning "what the client expects from the engineer" is directed mainly at the design and construction of metallic ore concentration or beneficiation plants. However, practically the same conditions apply to the design and construction of cement and lime manufacturing facilities, with the exception that the latter facilities reflect the client's and engineer's concepts of customer service and in some cases reflect promotional considerations for the product manufactured and distributed. The client expects his engineering contractor to contribute in an efficient, cooperative, and economical manner current industry-wide know-how and experience to the specific project under consideration through the client's organization

Jan 1, 1969

By J. J. Gusek

The Riley Pass strip mine is an abandoned uranium-bearing lignite deposit in Harding County, South Dakota, covering about 150 acres of highwalls, pit floor and mine spoils exhibiting elevated levels of radioactivity. Six reclamation design alternatives were developed, ranging from doing nothing to reclaiming to approximate original con-tour. The alternatives were evaluated for expense, site stabilization, and mitigation of public safety hazards. A comparative economic evaluation on three of the alternatives was completed for the Forest Service in selecting an alternative and substantiating federal funding requests. This evaluation included economic impacts associated with physical and radiologic health hazards, affects on recreational users, socioeconomic impacts and environmental improvement.

Jan 1, 1995

By Anand Kumar, Debasis Deb, A. K. Mishra, M V. N. S. PRASAD.

In the Adriyala project, shield-leg pressure data from all shields and shearer location with time stamp from a mechanized longwall face are monitored and recorded in a surface computer. The data contain random noise due to power failure, leakage of legs, bad sensor readings, and other maintenance or geomechanical problems. An algorithm has been developed to detect mining cycle parameters such as setting and final pressures and duration of the cycle from these data for the analysis of periodic roof weighting phenomena. The intensities and persistence of periodic roof weighting are vital information for mine management to make judicious decisions on longwall operation.

By S. M. Robinson

Wollastonite is recognized as one of the most unique, non-metallic minerals in the world. Its history for use in industrial applications is recent compared to other minerals, however, its distinctive physical properties, such as acicular particle shape, and alkaline pH creates incorporation possibilities ranging from bowling balls to automotive fascia, from ceramic tiles to automotive brakes, and from thermal insulation board to industrial and trade sale coatings. Its future use will be impacted by the exploitation of deposits which will ensure maintenance of the acicularity and purity of this naturally occurring mineral. Additionally, closely held surface treatment technology will open up additional niches requiring highly engineered performance.

Jan 1, 1995

By T. H. Parker

The Guasare Coal Project is located a short distance from Lake Maracaibo, in the Northwestern region of Venezuela. In 1987, Carbones del Guasare, a joint venture comprised of Carbozulia, ACC Venezuela, a subsidiary of ARCO, and AGIPCoal of ENI Group, Italy, was formed to develop the Guasare coal reserves for world markets. Drilling with the Venezuelan state of Zulia has indicated a coal resource of over 6 billion metric tons. Further exploration has delineated the Guasare deposit as an area particularly suited for cost-effective surface mining. The calculated mineable reserves of this area (300 million metric tons) and the coal quality characteristics are based on extensive core drilling programs.

Jan 1, 1989

By John L. Ellenberger

Virtually no two mines operate with the same geographic, geologic, and mining conditions. It follows chat problems vary with the conditions from mine to mine or often from one section to another in the same mine. Actual situations are described, and a technique of "stacking" maps to predict hazards is presented. Two case histories of the use of multiple overlays are de- scribed. The first deals with a property that was examined before the start of mining. The second is a property in which severe ground control problems were encountered and the relationship between the problem areas and known conditions were found to be related.

Jan 1, 1981

By V. Karra

Based on extensive investigations on the effect of design variables on process performance, during 1982-85, Nordberg developed a 1000 hp cone crusher, with the objective of boosting crushing productivity in existing plants. The 2390 fits on the same foundation as the 7' SHD Symons cone, but is designed to give two times the capacity of the 7'. The economies of scale involved give the customer substantial cost savings. In this paper process performance of the Nordberg 2390 relative to the 7' SHD Symons cone, while crushing the same ore, will be presented. Also, implications of such a crusher scale-up to associated cost savings will be addressed.

Jan 1, 1988

By F. D. Wicks

This paper summarizes the direct operating cash costs for the Barrick Mercur open pit gold mine. A comprehensive, detailed system of cost management has been in effect for the life of the Mercur operation. This system provides the basic data for operations control and is the basis for drafting budgets as well as analyzing impact of change on operations costs. The ore body is complex geologically and metallurgically, requiring operators to pay close attention to mining and processing costs. The cost history provides data which enables analysis of changes in production levels, aging of the mine production fleet, and the impact of specific cost changes through time.

Jan 1, 1993

By H. H. Hayden

The accident repeater-40 you have one at your mine? Unless your company is vastly different from most coal companies, you will find that a small percentage (11-12%) of your employees will have a large percentage (47-50%) of your accidents. When you find out that this is a fact, what do you do? First, you establish a set of guidelines that can be used in identifying the ?accident repeater?. Next, you determine the type of action necessary to improve work habits and safety performance of the accident repeater. With these two steps in mind, objectives are developed for an ?accident repeater? program.

Jan 1, 1984

By K. V. Raj, R. Jacksha

Conveyor systems persist in being a source of injuries and fatalities in the mining industry. To reduce these incidents, better methods are needed to enhance the monitoring of probable hazards and improve situational awareness during the normal operation and maintenance of conveyor systems. To address these issues, researchers from the U.S. National Institute for Occupational Safety and Health (NIOSH) continue to investigate emerging technologies that show the potential to improve miner safety around conveyors. This paper presents a feasibility assessment by NIOSH researchers of a fully integrated, commercially available wireless Internet of Things (IoT) system to improve situational awareness around conveyor systems.