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By R. C. Freas

Limestone is a basic raw material in the production of cement, lime, a wide variety of industrial products, and a significant percentage of the crushed stone produced in the United States annually. It is used in fluxes, glass making, mineral fillers, environmental applications such as flue gas desulphurization and water treatment, soil conditioners, animal feeds, and as a construction aggregate. This presentation provides an overview of limestone distribution in the United States, it’s production, the variety of products produced, and a brief review of the primary uses for limestone.

Jan 1, 2006

By J. Dasher

Regarding the March 1991 ME technical paper by De Souza and Moore: For more than a decade since my February 1981 article on how to use modern metric, which SME-AIME had decided to do, I have monthly pointed out metric errors to the editors. In part, I do this because there has been no action to al low editors to fix figures and tables or to allow them to require authors to do so. The latest resulting atrocity provokes this discussion of vibrating drill handle units being stated in decibels.

Jan 1, 1991

Dunn has written an excellent paper providing a wealth of advice on what is often the most costly consumable in the mineral processing plant. As he pointed out, grinding media selection and quality control can play a major role in successful plant operation. Owing to the economic importance of this topic, there are some important factors related to media sizing that I believe merit further comment. Dunn made reference to a slightly simplified version of the Azzaroni (1981) equation and pointed out its successful use for the Henderson SAG and Climax ball mills.

Jan 1, 1991

By C. J. Barbee, P. J. Bethell, C. J. Wood

Heavy medium cyclones (HMCs) are commonly used to clean run-of-mine coal in the 50 x 0.5 mm size range. Unfortunately, field studies suggest that industrial HMC circuits are often poorly designed or improperly operated, resulting in significant losses of recoverable clean coal. To assist plant engineers in overcoming these problems, a spreadsheet-based simulation package has been developed to predict HMC performance based on mathematical expressions originally developed by Wood (1990). A case study is provided to illustrate the predictive capabilities of this simulation package for an industrial HMC.

Jan 1, 2004

By D. R. Taylor, R. G. Goss

The use of clay granules as carriers for pesticides dates from the early 1940's and by the present day represents a business conservatively estimated at between 200 - 300 thousand tons / year in the U.S. alone. Aside from economic and specific target pest efficacy advantages, the use of clay granules as pesticide carriers also delivers a number of environmental benefits which will be reviewed. Topics to be discussed will include: 1) drift control (versus liquid sprays), 2) mobility (in the environment), 3) worker safety, and 4) transportation (spill) safety.

Jan 1, 1999

By A. C. C. Pacheco, L. C. Bertolino, M. L. Torem

On account of geological characteristics, Brazil is a country of large deposits of high quality kaolin, with the larger ones being located in its northern region. In the last years, kaolin beneficiation and production area is receiving great investments, aiming at a high quality kaolin production to be used in the paper industry, mainly intended for the foreign market. After the conclusion of expan- sion programs and with the advent of new production areas, Brazil is very soon expected to come in second place in the kaolin world production ranking.

Jan 1, 1998

By William L. Hodgson

HOARDS was written to fill the needs of an active minerals explorer. It permits retrievals using a number of spatial functions as well as direct relational logic, and enables statistical analysis within the system. Specified for use by non-EDP oriented staff, HOARDS also offers functions to subset, transform points to polygons of influence, and to calculate polygon overlap, enabling ready and efficient conversion of databases containing point oriented sample data to area/volume mine planning format. Both the design and implementation to date, and proposed enhancements are discussed.

Jan 1, 1979

By M. Karmis, C. Haycocks

Geographic Information Systems (GIS) are becoming a more commonly used tool for resource estimation as they provide not only a database management platform, but also the graphical capabilities to visualize resource characteristics. Interpolation methods used commonly in these resource studies do not typically provide a quantitative answer to the question: "How accurate is the estimate?" By comparing localized measurements at several locations to the interpolated thickness distribution used in a resource estimate, a quantitative analysis of accuracy can be obtained. The technique is demonstrated with a case study from Central Appalachia.

Jan 1, 1999

By P. R. Sheorey, D. Barat, B. Singh

Presented is a stability analysis for a trial stope in a lead-zinc mine. The trial scope would have an excavation width of 20 m with an initial height of 3 m. Filling would commence when the scope was heightened to 6 m. A two-pronged approach to predict the stability of such an opening was used viz. the finite element method and the rock mass classification method. Corroboration is shown to exist between the two methods. Deep borehole extensometer observations during stope extraction have been compared with predicted displacements.

Jan 1, 1981

By Richard J. Frechette

Final reclamation of mine tailings impoundments typically involves addressing the broad issues of surface stabilization and water management. Surface stabilization includes immobilizing the tailings particles and providing long-term protection of the containment facility. Water management typically includes provisions for handling both the external water (rainfall and runoff) and the internal water (pore fluids). Wet tailings disposal facilities, and sites with limited access and steep topography, present challenges to implementing effective surface stabilization and water management plans. This paper presents a generalized discussion of the approach to tailings impoundment reclamation based on project experience.

Jan 1, 1995

By Evert Hoek

Two types of failure have to be considered in designing large openings: (a) Structurally controlled failure caused by discontinuity intersections, (b) Stress induced instability which occurs when induced stresses exceed the rock mass strength. Structurally controlled failures, which occur in hard jointed rock masses at relatively shallow depth, are briefly reviewed. This paper is primarily concerned with stress induced instability at greater depths and with the problem of estimating the strength of a rock mass surrounding an underground opening. Some of the practical aspects of support design for large openings are discussed.

Jan 1, 1981

By D. Robert Weir, Roman M. G. S. Berezowsky

Pressure oxidation of gold containing concentrates and ores is an effective pre- treatment for liberating refractory gold. This is particularly true when an appreciable portion of the gold is associated with sulphides and is not amenable to conventional cyanidation. A brief review of the literature on the pressure oxidation of refractory gold materials is presented. The chemistry of the aqueous oxidation of arsenopyrite and pyrite is discussed. Data obtained on the pressure oxidation and subsequent cyanidation of concentrates and ores tested at the Sherritt Research Centre are also presented.

Jan 1, 1984

By J. H. Ahn, J. E. Gebhardt, W. K. Tolley

Color measurements were made for pure minerals, mineral mixtures and flolation froths loaded with different minerals. The research objective eras to correlate color with the composition of mineral streams. An industrially available system consisting of a fiber-optic-based illuminator and detector was used to measure color. The color values of binary mineral mixtures varied according to the type and proportion of minerals in the mixture. The measured color values of mineralized froths in the laboratory and in a commercial flotation circuit were dependent on the amount and type of minerals present.

Jan 1, 1994

By K. J. Stanaway

Environmental pressures on waste disposal are forcing pigment producers to use feedstocks with higher Ti02 content and lower levels of trace elements. Despite this, 50% of the world's Ti02 comes from ilmenite concentrates with only 37% to 54% Ti02. An industry growth rate of 25% in the next 10 years, combined with trends to diminishing resources and lower mining grades for rutile (95% P02) and leucoxenized ilmenite (55% to 90% P02), means that unless new discoveries are made soon, the industry will become even more reliant on ilmenite.

Jan 1, 1995

By Jim Avraamides

The properties of activated carbon which are important for gold recovery applications include activity, capacity, wear resistance, particle size distribution and bulk density. There are experimental difficulties in attempting to simulate the plant environment in the laboratory in order to measure the above properties. However, standard tests can be set up to compare the characteristics of different carbons and to assist in monitoring the performance of carbon in CIP operations. These laboratory tests are critically evaluated and data are presented on the performance of carbon from a number of CIP plants.

Jan 1, 1989

By R. Krishna, L. A. Kumar

The paper suggests a new empirical model for predicting mining subsidence. The parameters considered are Lithological Factor, which in this context meant percentage of sandstone, Rock Mass Factor (depending upon the RQD value of drill-hole cores), width: depth ratio and percentage extraction of coal. More than 250 drill-hole cores from seven longwall panels and 11 bord-and pillar (room-and-pillar) workings were analyzed from an extensive data bank of Singareni Collieries Company Ltd. (S.C.Co.), Andhra Pradesh, India. Excellent subsidence agreement was found with the suggested model.

Jan 1, 1993

By R. J. Snoby, P. Grotjohann

In processing heavy-mineral sands, the low feed concen¬tration and respective high value of the desired minerals require high-capacity production and sharp classification/ separation techniques to reduce the specific production costs. This paper describes the new allfux® separator, which can economically accomplish these criteria. The separator is a two-stage process that combines rising current and fluidized-bed technology. This allows for the treatment of ex¬tremely high mass flows in a single unit. This paper reports on test work performed on coal, iron ore and heavy minerals.

Jan 1, 2000

Maptek I-Site laser scanning expertise and software technology is being used to map the geology and layout of the deepest underground laboratory to be established in the U.S. The Deep Underground Science and Engineering Lab (DUSEL) in the former Homestake gold mine in Lead, SD, will provide for scientific studies in particle and nuclear physics, geology, hydrology, geo-engineering, biology and biochemistry. The project, funded by the National Science Foun¬dation (NSF), will allow geoscientists and engineers to research the behavior of subsurface rock, minerals, water and energy sources

Jan 1, 2010

By T. Y. Yan

O2, NaCl03, H202, NaOCI and Ce+4 have been examined as oxidants in an alkaline carbonate system for uranium in situ leaching. The South Texas and New Mexico ores contained up to 2.6 meq/g of reducing compounds that consume oxidants in the leaching operation. Leaching rates did not increase linearly with the oxidation potential of the oxidants. A mild oxidant can be used to maximize uranium oxidation selectivity and oxidant efficiency. 02 can oxidize most of the uranium mineral with an adequate rate and high oxidant efficiency.

Jan 1, 1993

By Ernest Y. Baafi

The usual tasks performed by a mine store include .removal, replenishment, ordering and deletion of items and updating of stocks. A personal computer Mine Store Inventory Database System MIDSYS for monitoring stocks in such a store is presented. The system consists of series of relational databases developed in dBASE III+ environment. The system has three main modules comprising of a store management module, a display module and an employee-store operation module. The third module is useful in tracing movement of store goods. The MIDSYS is menu .driven with help functions at all levels.

Jan 1, 1992