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A new fluid bed lime calcining plant is converting high quality limestone into quicklime at the Cape Lime facility in Vredendal, South Africa. The plant was supplied by Metso Minerals. Cape Lime, established in 1946, operates two limestone and dolomite mines in South Africa. The high quality Vredendal limestone deposits are suitable for the production of lime for water treatment and for manufacturing precipitated calcium carbonate.

Jan 1, 2003

By R. E. Johnson, L. V. Araújo, B. R. Palmer, L. M. Abrantes, G. W. Warren

The behaviour of chalcopyrite - mineral specimens and a Portuguese concentrate - in 2M chloride solutions prepared from hydrochloric acid and sodium chloride, has been characterized by cyclic voltammetry. The study has shown the influence of the potential and of the presence of impurities in the reaction schemes and their relative extent. The dissolution of chalcopyrite concentrate under potentiostatic control has been investigated and found to confirm the effect of the selected potential on the surface modification/rate of dissolution. An attempt has been made to correlate the information obtained with the response of the concentrate electrode to constant current treatments.

Jan 1, 1993

By J. D. Raulerson, R. P. Farias, G. A. Gruber

A flotation process has been developed to successfully treat ore from the Santo Domingo phosphate deposit in Baja California Sur. The ore contained less than 4% P2O5 with quartz, silicates, and carbonates as gangue minerals. Flotation of the low- grade feed in seawater required that the conventional Crago process, comprising direct anionic flotation, deoiling, and inverse cationic flotation, be augmented by an anionic cleaner flotation step, phosphate depression, and a calcite flotation step.

Jan 1, 1988

By Marietta Canty

Results are presented that were gathered during field-scale testing of an innovative technology, sulfate-reducing bacteria (SRB), designed to treat and control acid mine drainage (AMD). The project was performed under the Mine Waste Technology Program (MWTP), which is funded by the U.S. Environmental Protection Agency (EPA) and jointly administered by the EPA and the U.S. Department of Energy through an Interagency Agreement. The MWTP is implemented by MSE Technology Applications, Inc., located in Butte, Montana. A field-scale test is described in which the subsurface workings of an abandoned mine were used as an "in situ biological reactor."

Jan 1, 2000

By C. H. Bucknam

A suite of ore and waste rock materials was selected for the interlaboratory testing of combustion-infrared ("Leco") methods used to estimate carbonate and sulfide minerals present in test materials. The objective of the study is to develop ASTM standard methods to be used for metallurgical characterization of ore, acid drainage prediction for ore and waste during ore body evaluation, and for ore and waste control during the active mining of ore deposits. The results may be interpreted for classification of the materials according to their carbonate-sulfide or acid-base characteristics based on net carbonate value (NCV). The test materials were processed by x-ray diffraction and x-ray fluorescence (XRD-XRF) at Newmont Metallurgical Services (NMS) to obtain a semiquantitative mineralogical composition. Results of the interlaboratory testing for total carbon-sulfur, pyrolysis loss carbon-sulfur and hydrochloric acid residual carbon¬sulfur are compared with the mineralogical composition to aid in interpretation of the NCV classifications of the samples.

Jan 1, 2002

By Malcolm J. McPherson

Within the world of mining health and safety, increasing attention is again being given to underground fires and explosions. This paper reviews the effects of open fires in mine entries on the ventilation system, and outlines current methodologies of attempting to control such a fire. The particular hazards of a fuel-rich fire are discussed. There appear to have been no really significant advances made in methods of extinguishing mine entry fires in the last several decades. The final section of the paper introduces research that is investigating the simultaneous production of an inerting, cooling and quenching atmosphere by means of a dense water fog.

Jan 1, 1993

By Antoon W. van der Vooren, Colin R. Phillips

A comparison of analytical models used to describe deposition in the first generation of lung bifurcations is presented. In order to allow testing of the mathematical models, experimental data were obtained from radon daughter deposition in simplified lung bifurcations. The experimental data for particles deposited by diffusional mechanisms is best described by the assumption of a thin concentration boundary layer at the entrance of a right circular tube. Other more complex models do not accurately describe the deposition of submicron particles. The angle of bifurcation was found to have a minor effect on deposition.

Jan 1, 1981

By Hill McDonald

Sand and gravel deposits may be explored by many different methods. The methods used by The Standard Slag Company are primarily two in nature. One is using an auger which is limited in depth by various soil conditions. The other is a heavy wall dry sampler and a heavy wall wet sampler. The heavy wall dry sampler takes continuous uncontaminated samples up to seven inches in diameter. The heavy wall wet sampler takes continuous uncontaminated samples up to six inches in diameter. For us, the maximum depth of the heavy wall samplers has been two hundred fifty feet of which one hundred feet was above the water table and one hundred fifty feet was below the water table.

Jan 1, 1972

By Walter J. Johnson, Robert L. Chufo

A unique non-contracting coal thickness measurement technique has been developed to measure both the dielectric constant and thickness of a coal seam as part of a sensor array supporting an autonomous coal mining machine. The sensor measures the reflection of an electromagnetic signal from the coal/shale interface. Underground measurements of coal 6- in thick with a dielectric constant of 4 have been confirmed. Measurements were also made of a 31-in thick coal pillar for application of the sensor to highwall mining. The electromagnetic measurement technique, the data reduction process and field test experience will be presented.

Jan 1, 1992

By B. C. B. Pretorius

A heat load analysis of the very hot sub-shaft area of Loraine gold mine situated near Welkom, South Africa, showed. that the heat that needed to be removed to give acceptable wet-bulb temperatures at the working faces could not be done by the normal ventilation air alone, but would have to be complemented with extensive refrigeration. The paper outlines the considerations in selecting the cooling system adopted for this shaft.

Jan 1, 1980

By S. K. Nandy, K. F. Unrug

The behavior of the immediate shaly roof within a drift mine in eastern Kentucky, operating in the Coalburg seam, was monitored with roof bolt dynamometers. The dynamometers used were capable of providing readings up to a maximum load of 66.72 kN (15,000 lbs), + 0.022 kN (5 lbs). To observe the influence of moisture on the rate and extent of roof deterioration, 57dynamometers were installed on roof bolts anchored in intake and neutral airways. Monitoring was conducted during the period January 1985 through January 1986, in order to cover a full cycle of dry and wet mine conditions associated with seasonal changes. Analysis of the data showed a trend of roof deterioration induced by condensation and eventual penetration of moisture within the immediate roof bedding planes, leading to rapid disintegration of the mine roof.

Jan 1, 1987

By Graeme J. Jameson

A form of column flotation cell is described in which the contact between the feed and the air stream is made in a mixing device at the top of a vertical downcomer. The air-liquid mixture flows downward to discharge into a shallow pool of pulp in the bottom of a short cylindrical column. The bubbles disengage and rise to the top of the column to overflow into a concentrate launder, while the tails are discharged from the bottom of the vessel. The main advantages of the device described are that the overall height of the column is reduced to about one metre (3 ft), and the column can be self-inducing with respect to the air supply. Experimental results are given from tests on a feed stream to a conventional zinc cleaner circuit. Using wash-water to reduce gangue entrainment, the column gave high concentrate grades and high recoveries.

Jan 1, 1988

By W. H. McDonald, D. D. Carr

The use of stone in building construction predates written history. From the time that stone was first used, builders have constructed stone buildings predominately from local or regional materials. However, since World War II, the stone business has become increasingly global. For example, French limestone is now sold to builders in the United States, and American granite is shipped to Japan. The internationalization of architectural and construction firms has encouraged this trend. Differences among nations in trade practices, environmental demands and the level of knowledge of dimension-stone characteristics make international trading in stone a risky and potentially disastrous business for unwary participants.

Jan 1, 1997

By Jeong-Heum Kim, Jan M. Mutmansky

A number of solution methods for solving the nonlinear equations derived from mine ventilation networks use meshes selected from the network as the basis of the solution techniques. Mathematicians working in network theory have outlined several methods for speeding up the computations through mesh selection and ordering procedures. In the mine ventilation area, a fair amount of attention has been paid by ventilation specialists to procedures for choosing the meshes so that the computational effort is eased. However, little attention has been paid to mesh ordering methods. This paper outlines research into random mesh ordering procedures plus two non-random mesh ordering procedures and compares some results using these procedures within four solution algorithms.

Jan 1, 1993

By S. P. Lucido, I. Iwasaki

The potential of controlling heavy metal ions in effluents from discontinued mining operations and waste rock piles has been investigated. A fresh water green alga, Cyanidium caldarium, was found to have the potential to remove Cut' from solutions while exhibiting high tolerance to acid conditions which are commonly encountered in copper-nickel mine drainage. The process has the potential for application as a low maintenance metal decontamination system. The growth requirements and copper removal characteristics of this microorganism are described.

Jan 1, 1991

By L. Korkiala-Tanttu, M. Rinne, Z. Song

Disposal of mine tailings has been recognized as an unavoidable burden of mining companies and local authorities. Conventional methods dispose mine tailings in a passive manner which hardly generates any value from them. On the other hand, growing local communities close to mines need more infrastructures which require great amounts of raw materials. In view of the above mentioned situation, a novel utilization of mine tailings is explored as alternative material for asphalt pavement, in order to extract more value from mine tailings and solve the high cost of pavement material. Inherent physical properties of the mine tailings were first investigated to find out their availability as pavement material. Then test specimens were made as mixture of the mine tailings and other pavement material to be tested in laboratory. The mine tailing materials presented a considerable potential as asphalt filler for low-volume roads. Furthermore, the limitat

Jan 1, 2011

By B. A. Donahue

The results of a survey of 46 West Virginia coal samples, employing the Office of Coal Research-Band coal sewage treatment process, indicated that the Freeport coal and Bakerstown coal from Preston County, Pittsburgh coal from Harrison and Ohio County and the Sewickley coal from Monongalia County offer outstanding potential for water clarification. Oxidation, steam treatment and acid and base washing of coal generally resulted in small positive or negative changes to the water clarification capacities of the coal while the employment of prepared coal fractions resulted in more significant benefits. Of the coals tested, those fractions with high ash, high sulfur and low Btu generally possessed the highest adsorption capacities.

Jan 1, 1968

By Y. J. Wang

This paper describes a procedure for solving the generalized system of n network equations in n unknowns considering the following ventilation variables and parameters: (a) air quantities, (b) pressure losses or gains caused by the control devices (i.e., fans or regulators), (c) resistance factors, (d) natural ventilation pressure, and (e) fan pressures (as a function of air quantities). The air quantities and pressure losses for all branches in the network are grouped into dependent and independent variables. The branches with an independent quantity are contained in a chord set, and the branches with a dependent pressure loss are contained in a chord set. In addition to the problem formulation, the solution procedure, applying the Newton method, is discussed and illustrated with a numerical example.

Jan 1, 1989

By Mandira Madhuchhanda, N. B. Devi, P. C. Rath, R. K. Paramguru, K. Srinivasa Rao

An experimental investigation of the dissolution of three base-metal sulfide minerals, namely, CuFeS2, ZnS and PbS, in hydrochloric acid medium in the presence of manganese dioxide is reported. Polarization measurements and leaching studies were employed in the study. Dissolution occurred in the following three ways: by the cyclic action of the Fe3+/Fe2+ redox couple, by galvanic interaction between Mn02 and the sulfide minerals, and because of chlorine evolution from the system. The later two routes were found more effective at higher HCI levels. PbS appeared to be oxidized easily, whereas CuFeS2 was the most difficult to dissolve. ZnS dissolution fell in between PbS and CuFeS2.

Jan 1, 2002

By Allen V. Reicks

Modern conveyor pulleys are welded steel structures subjected to dynamic loads. In this paper, fatigue notch and fracture mechanics methods are applied to several weld joints on typical pulley constructions. These methods are used to analyze field applications and are correlated with laboratory testing. Generalized approaches are presented which provide high confidence in pulley design with corresponding high reliability.

Jan 1, 1996