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By E. W. Sawyer

Attapulgite is a magnesium aluminosilicate clay mineral which exhibits unique, processing-enhanceable physical and chemical properties that are related to its current commercial uses. Properties of commercial interest are gelling, absorption, adsorption, binding, acid neutralization and many others. Major industrial applications are: (1) absorption by heat treated grades utilized in industrial oil and grease absorbents and in agricultural pesticide carriers; (2) gelling of aqueous liquid products by colloidal grades for stabilization and viscosity control in salt water drilling fluids, suspension fertilizers, liquid animal feed supplements, paints and tape joint compounds; (3) adsorption by heat treated varieties for the removal of catalysts, color bodies and other polar compounds from hydrocarbon streams; (4) gelling of organic liquids by colloidal attapulgite/surfactant blends in oil-type paints, fibrated and nonfibrated asphaltic coatings and mastic compositions, and (5) the binding of feeds and molecular sieve sorpents with colloidal type attapulgite products. These applications and other less common uses and potential uses will be discussed along with, the necessary selective mining and plant processing features related to each property and application.

Jan 1, 1986

By Thomas S. Bubanovich

This paper will discuss the installation and operation of the Mundix Monitoring System at the Freeman United Coal Mining Company's Orient No. 4 Mine. Detailed explanations of the objectives set by Management, description of the mine, description of the system, installation procedures, and material used, operating procedures, maintenance procedures, and personnel requirements as well as experiences with carbon monoxide monitoring.

Jan 1, 1987

By Joseph D. Martinez

Salt, because of its plasticity, exerts a major influence in deformation. Resulting salt structures are common world-wide. A special type, salt domes, are associated with thick sequences of sediments deposited over salt. Their upward intrusion is generally thought to be in response to buoyancy. Mines in salt domes reveal an internal pattern compatible with large amounts of vertical flowage. Caprock, the end product of accumulation of anhydrite from salt dissolution, attests to long continued upward growth and concomitant truncation by moving underground waters. Concepts of modes of growth are evaluated and related to problems in utilization.

Jan 1, 1979

By Mark L. Munsell

In recent years, miners have tried many approaches to maintenance such as: - Highly sophisticated computerized programs. - large planning groups designed to preplan and schedule work. - Contract maintenance. - Break down maintenance. Each of these approaches has faced the added constraints: - High replacement cost of equipment necessitating longer useful equipment life - management?s increased scrutiny of all indirect costs such as maintenance. Faced with these factors, what system of maintenance control is right? After visiting many properties recently, it appears there is no right system. Maintenance programs need to be tailored to the people and production constraints that occur at an individual property.

Jan 1, 1976

By K. Marutiram, T. Umadevi, R. Sah, K. Abhishek

Low-grade iron ore received from the West Singhbhum area of Jharkhand state in India was used to develop a beneficiation flow sheet to remove alumina (Al2O3) and silica (SiO2 ) from the ore to get iron (Fe)-rich product for steel plants. Mineral characterization showed that the main mineral constituents present in the head sample are goethite, limonite, hematite, quartz, clay and gibbsite. The head sample contained about 49.2 percent Fe, 8.79 percent alumina and 12.01 percent silica. The received iron ore sample is amenable to upgradation through beneficiation to get pellet grade concentrate. The beneficiation process was established, involving crushing, screening, jigging, spiral separation, size reduction, desliming and magnetic separation. The process showed significant enrichment in Fe values to 63.5 percent Fe in concentrate, from 49.2 percent Fe. From the developed flow sheet, it is possible to obtain pellet grade fines with 63.5 percent Fe, 2.92 percent SiO2 and 2.61 percent Al2O3 with 50.6 percent weight recovery. The overall tailing loss is 49.4 percent with 34.3 percent Fe, 21.28 percent SiO2 and 14.64 percent Al2O3

By Matthew J. Hrebar

A comparison of hydraulic shovels (HS) versus front-end loaders (FEL) is commonly made when an excavator with some degree of mobility and medium reach is required. These applications are often found in hard rock open pit and surface coal mining applications, among others. The purpose of this paper is to present a comparative economic study of the two excavators. Production data was collected from both HS and FEL manufacturers as well as operating mines. Availability, operating costs, and estimated operating life were gathered from operating mines, while capital costs were obtained from manufacturers. The data was limited to studies and operations which included both types of mid-size excavators. The economic study is followed by a discussion of other factors considered by mine operators in excavator selection. The study was originally made for a presentation at the 23rd Intermountain Minerals Conference at Vail, CO.

Jan 1, 1992

By J. K. Shurie

Calcined high quality bauxite is a staple raw material of the abrasive industry world-wide. The author discusses the factors which affect the economic value of calcined abrasive grade bauxite, and proposes an approach to the problem of estimating the relative value of available materials.

Jan 1, 1990

By Molood Saeedi, Nima Sadeghi, Eskandar Keshavarz Alamdari

This study showed the kinetics of gold chlorination leaching from an anode slime complex containing copper, silver, barium, selenium, and tellurium. AgCl and BaSO4 control the rate of gold leaching, and the interface transfer and diffusion across the product was selected as the desirable kinetic model. The concentration of hydrochloric acid, chlorine gas flow rate, pulp density, and temperature have been precisely studied. The results showed that temperature and hydrochloric acid have a favorable influence on the leaching rate. However, the chlorine gas flow rate is inactive in the reaction rate. Furthermore, the leaching rate decreased with an increasing pulp density. The leaching process was controlled by the interface transfer and diffusion across the product, and the activation energy was determined to be 13.66 kJ mol–1.

Oct 19, 2021

By J. J. Bean

The development drilling program of the Copper Cities mine indicated that the molybdenum content of the ore would be about 0.011% MoS2' The molybdenum content of the Miami mine at the same time was about 0.025% MOS2' The Miami mill had a very successful molybdenum operation which used bleeder turbine steam from the Miami power plant for the steaming operation. The much lower grade of the Copper Cities ore, the absence of a source of low cost steam and the use of sodium aerofloat as the copper collector which Miami experience indicated did not respono readily to the steaming technique made very doubtful the success of a similar operation at Copper Cities. However, the relatively few pounds of copper that could be recovered from the low grade Copper Cities heads made very desirable the recovery of the molybdenwa,as a source of additional revenue. Accordingly, shortly after the Copper Cities mill began operation, a research program was instituted to develop a suitable method of molybdenum recovery. This program explored first, the successful steaming process then in use at Miami and as expected, found it unable to decompose the sodium aerofloat copper collector. The known chemical depressants were then tried without much encouragement. Finally the copper concentrate was dried, not roasted, to 2-3% mOisture and this along with sodium ferro-cyanide and cyanide resulted in sufficient copper depression that a final molybdenum concentrate containing 1.0% CU could be made. The bench scale testing was followed by pilot plant testing. Sixteen

Jan 1, 1972

By Christopher Haycocks

Self-supporting, open stoping underground mining methods are some of the earliest, starting with the prehistoric flint mines of Europe and the Egyptian gold mines of Nubia in the time of the pharaohs. When the early miner created an opening, it had to be inherently stable and self-supporting to enable him to continue. Therefore, as mining progressed beyond simple gophering, self-supported open stoping methods were devised to meet the needs of individual ore bodies. Timber for support appears in mines as early as 1000 BC, but this was for no more than local ground control. The ingenuity of mining engineers through history has so refined open stoping methods that today they produce more tonnage than any other mining system. Self-supported open stoping finds its application in moderate to strong rocks that exhibit little jointing or fiagmentation. Good back, hanging wall, and footwall conditions that require no more than incidental support are an essential part of these mining methods. Open stoping methods find applications in all inclinations of ore body from flat to vertical, and where ore movement may be either mechanical or under the influence of gravity. Table 18.0.1 demonstrates the range of ore bodies suitable for open stoping, with particular reference to their dip and the deposit thickness. Most of the flat-dipping applications use ore pillars for overall support and ground control that may be recovered under some conditions after completion of normal stoping practices. In steeper ore bodies, rib, crown, and sill pillars used to block out the ore may be recovered subsequent to the completion of stoping. Open stopes are frequently filled to facilitate pillar recovery. Two of the methods, vertical crater retreat (VCR) and shrinkage stoping, utilize fragmented ore for temporary support in the stopes. In these two cases, the stope is not strictly open until after drawdown.

Jan 1, 2008

By H. Bradley Johnson

A number of Federal laws affecting safety and health in the mining industry has been enacted and revised over a period of many years. We have tended to classify these laws and their applicability into three categories: 1) coal mines, 2) metal and nonmetallic mines, and 3) mines with Federal supply contracts. With the growing attention which is being given to mine safety by the Federal government, the entire mining industry should keep aware of all developments in the administration of each of these laws.

Jan 1, 1970

By Jennifer King, Julius Strid, Steve Brandon

The Upper Hidden Basin Diversion (UHBD) tunnel was driven approximately 1.2 miles by the drill-and-blast method primarily through massive granite bedrock geology for the Kodiak Electric Association, Inc. (KEA) in Kodiak, Alaska. The tunnel was driven from both portals with a constant 11-ft straight-leg horseshoe cross-section. The design and construction of the tunnel was driven by logistics and weather conditions due to its remote location and the rugged terrain of the project setting. This paper will discuss the successful completion of a challenging project over a ve-year period from preliminary planning through the design and construction phases.

Jun 23, 2024

By M. S. Safarzadeh

Cu-As feedstocks are among the most problematic copper sources that have been avoided over the past years. The high arsenic content of such ores/concentrates combined with their refractory nature have directed the metallurgical industry towards developing efficient technologies for the treatment of high-arsenic copper ores/concentrates. As the most important member of Cu-As-S mineral system, enargite (Cu3AsS4) is frequently encountered in some of the important copper deposits. Several hydrometallurgical and pyrometallurgical processes have been examined for the treatment of enargite concentrates, but currently, no commercial operation exists. In an effort to develop an original processing option, an acid bake-leach process has been identified and applied to an enargite concentrate containing ~67% enargite, ~27% pyrite (FeS2), ~3% chalcopyrite (CuFeS2), ~6% sphalerite (ZnS) and <1% galena (PbS). Sulfuric acid baking of this concentrate resulted in the transformation of the concentrate to S8, As2O3, HFe(SO4)2?4H2O, PbSO4 and Cu0.47Fe0.53SO4?H2O, all of which (except elemental sulfur and PbSO4) dissolved during the water leaching step. More than 87% Cu and 64% As were leached when the concentrate was baked at 200°C over 7 h with a sulfuric acid to concentrate weight ratio of 1.6. Less than 1% As was lost to the gas phase. Upon water leaching, copper and arsenic were released to the solution at a concentration ratio of about 3:1. While enargite is very reactive during the sulfuric acid baking reaction, other minerals present in the concentrate such as pyrite, galena, and sphalerite may compete to consume sulfuric acid and be converted into their corresponding sulfates at different levels. The purpose of this paper is to evaluate phase transformations during the acid bake-leach process for the treatment of an enargite concentrate, and to study the effect of sulfuric acid dosage on the extraction of Cu, Fe, and As. In this regard, the concentrate, baked concentrate, and the leach residues are characterized and a conceptual process flowsheet is described for the acid bake-leach process for the treatment of enargite concentrates.

Feb 23, 2014

By H. M. Lima, P. Wathern

There are many different words to describe mine closure, including rehabilitation, reclamation, restoration and decommissioning. Closing mining operations, mainly open pit mines, has required resolution of numerous issues. Mine closure plans involve environmental-protection issues, regulatory issues and community issues. The obvious, and often most expensive of them, is the physical rehabilitation of the disturbances and the elimination of long-term commitments and maintenance. This paper outlines mine closure planning and its important component, mine-site rehabilitation. Community consultation and involvement are also referred to as an important component of the mine-closure plans, which are required to ensure satisfactory mine site rehabilitation. Considerations of socioeconomic impact of mine closure and long-term responsibilities are presented.

Jan 1, 2000

By Brad Grothen, Lok Home

The choice of TBM type is never easy, but it becomes especially challenging when faced with a hard rock tunnel with expected high water flows and pressure. Slurry Shield tunneling has a long history of being used in these conditions to minimize the risk, though this method has brought with it other risks along with cost considerations. At recent projects around the world, another method has been proven to effectively manage these project risks without utilizing Slurry Shield tunneling: Shielded, NonContinuous Pressurized (NCP)-TBM tunneling in rock with a comprehensive grouting program. In this paper, the authors will analyze the use of Shielded NCP TBMs at projects around the world as compared with slurry shield tunneling in rock under water pressure. Recommendations will be given in order to establish a clear picture of the optimal tunneling method.

Jun 13, 2021

By James A. Procarione, Sandip K. Mukherjee

The Department of Mining Engineering, University of Utah, has developed a thermodynamic-based mine ventilation simulator capable of predicting or analyzing the climatic conditions in hot underground environments. This compressible flow model, besides analyzing an operationally and legally-constrained network for mass and pressure balance, also takes into account various existing and anticipated sources of heat. Presently, three major sources of heat have been incorporated in the model. These include autocompression, wall-rock heat, and heat from equipment. A unique feature of this simulator which makes it distinctly different from its existing predecessors is the mathematical technique utilized to solve the network problem. Advantage has been taken of newer, more sophisticated mathematical and programming techniques to accomplish accelerated convergence and network solution generation. This paper describes in detail the development of the simulator including the mathematical relationships and the techniques used to predict the initial and final thermodynamic states of the mine air after its interaction with heat sources. The algorithm for solution to the network, computer model description, and the input data and program execution requirements are presented. A simple hypothetical network is used as a case study to illustrate the application of this simulator.

Jan 1, 1987

By C. Villa Diniz

It is proposed that battery grade Mn02 can be produced directly from a manganese ore from Azul Mine in Brazil, by leaching with HCI to remove heavy metals selectively. We are working to find a way of selectively separating Cu, Ni, Co, Pb and Fe from the resulting acidic manganese chloride solution, to detoxify it and produce marketable chloride solution. Chelating ion exchange resins are proving more promising for this separation than solvent extraction with commercially available reagents. Results from batch and column ion exchange tests that characterize the behavior of copper, nickel, cobalt, lead and iron are reported.

Jan 1, 1999

By J. R. Montgomery, T. A. Phillips, F. Blackham, D. J. Adams

Underground water, whether it is a mine seep, in situ leach solu­tion, or a pollution plume, is difficult to track and monitor. Monitoring wells are costly to drill and may be placed in the wrong spot. This report describes a test of an electromagnetic technique to track acid water draining from the Midnite Mine near Spokane WA. The tests successfully mapped the path of acid mine drainage being collected at the mine from two seeps. Several small side branches flowing to smaller seeps and a mix­ing zone where relatively clean water mixed with the acidic water, were also mapped. The study has changed previous opin­ions on the flow of water through the site and will be used as a basis for future site remediation planning.

Jan 1, 1996

Exploration for SX-EW copper deposits and plant operation depend largely on the copper and gangue mineralogy inasmuch as? they govern the feasibility of leaching. Mineralogical parameters are pivotal in identifying if an ore is suitable to dump, heap, thin layer, vat or agitated leaching and/or if the ore requires curing, bioleaching or alternate lixiviants. Problems in metallurgical testing, production leaching and recovery forecasting are very often related to lack of mineralogical data. This presentation will illustrate the use of quantitative mineralogical analysis for exploration, acquisition assessment and optimization of copper leach operations.

Jan 1, 1996

By Jan M. Andersson

This paper will discuss the background information about rock cutting tools used for soft ground excavation, their history and evolution. A brief review of the current state of the art manufacturing technology will be presented and some parameters related to the material used in the drag and conical type pick cutters and their impact on their life and performance will be explained In addition, the selection procedures for choosing the right bit for excavation of a particular geological formation will be reviewed A set of guidelines will be provided for initial selection of the tools for various machines and rock formations. The methods for estimation of the tool life in various materials and the influencing parameters along with limitations of the rock cutting tools will be discussed as well.

Jan 1, 1998