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By P. M. Sandgren, H. Al-Dabbagh

Saudi Company for Precious Metals (SCPM) is jointly owned by the Saudi Arabian state organization Petromin (The General Petroleium & Mineral Organization) and Boliden of Sweden. The company operates the Sukhaybarat gold mine in the Saudi Arabian desert and produces some 80,000 ounces of gold per year by agitation and heap leaching. The discovery, development, and operation of this mine is a success story. After the first drill hole intercepted a gold mineralization in 1983, it took the partners only 8 years to delineate the ore reserve, locate water sources, prepare pre-and final feasibility studies, obtain permits, design, and construct the facilities. Sukhaybarat, which is an open pit mine, started off with a carbon-in-leach agitation plant only, but a heap leach facility was added in the beginning of 1995. Since start of operation in the middle of 1991, a total of 300,000 ounces of gold has been produced in the first four years of operation at a very competitive cost.

Jan 1, 1996

By Kalyan K. Bhattacharyya

A systematic slope design for open-pit mines has become a reality only in recent years. Advances in the science of rock mechanics, coupled with extensive use of computers, have enabled the numerical solution of slope design problems which were not previously amenable to analytical or numerical solution. This slope stability study was performed for the UJV-SB open-pit uranium mine of the Getty Oil Co., located in the Shirley Basin area, Wyoming. The purpose of the study was to determine the appropriate slope angles for a starter pit. The data generated during the mining of the starter pit would test the initial design and suggest appropriate modification in the design for future mining in the project area. There had been a history of slope failures in the open-pit uranium mines in the area due to the low competency of the overburden materials and adverse hydrological conditions.

Jan 1, 1979

By R. R. Tatiya

The selection of a mining method for a particular deposit must be based on certain technical and economic criteria. This can be interpreted as maximizing extraction and productivity while maintaining safe working conditions and minimum costs. The methodology developed here examines some of these aspects. The proposed methodology was tested on copper deposits that could be mined by underground stoping methods such as sublevel stoping, cut-and-fill stoping and their variants. In general, it provides a practical approach to both method selection and optimum stope design for base-metal deposits.

Jan 1, 1998

By L. J. E. Hofer, L. F. Zeiler, D. A. Giardino

The Jones Trickett Ratio (JTR) is generally used in investigations of fires and explosions for the determination of the composition of the fuel. This paper takes a close look at the JTR and finds it unreliable and ambiguous for the determination of fuel composition. A new index is presented, termed the (H/C) Index which uniquely determines the fuel composition. The (H/C) Index is simple to use requiring only the results of a single gas analysis of the combustion products. Experimental data testing the (H/C) Index for methane, propane, ethylene and coal dust are given, showing that the Index unambiguously determines the composition of the fuel. The (H/C) Index is also applied to the gas analysis data of several mine fires, illustrating how the Index changes with the progression of the mine fire.

Jan 1, 1993

By R. Venugopal, T. C. Rao, J. P. Barnwal, K. Udaya Bhaskar

The performance characteristics of a multigravity separator for the recovery of heavy minerals of lead, zinc, copper and silver from a lead rougher-flotation concentrate were studied. Factorially designed experiments were carried out on three operating variables, i.e., the amount of wash water, the drum inclination and the drum rpm, of a multigravity separator. The experiments were carried out at two levels of each variable. With the experimental data, regression equations were developed for different metal grades and recoveries. The analysis revealed that drum speed has a major influence in determining the heavy-metal grade and recovery. Drum inclination is the next most important variable, with the amount of wash water being the least important. A concentrate containing 40% lead, 9.4% zinc, 1.5% copper and 1,400ppm silver was obtained with recoveries of 74.8%, 65.9%, 64.1% and 53.2%, respectively. Finally, the predicted values of grades and recoveries at intermediate levels are compared to actual experimental data to test the validity of the equations developed.

Jan 1, 2000

By P. Berendsen

The tectonic and sedimentary environment of the Central North American Rift System (CNARS) provides all excellent setting for major mineral deposits. Major north-northeast-trending high-angle normal or reverse faults and northwest-trending transcurrent fault systems may exercise control over ore forming processes. Gabbro and basalt are the dominant igneous rock types. Carbonatite and kimberlite occur in Nebraska and Kansas. Concentrations of Cu. Ni, Co, Ti, Au. Ag and PG-minerals are known to occur in this setting. Arkosic sandstone, siltstone, shale, and minor carbonate units occur on top of the rift basalts and in flunking basins where they may reach thicknesses of 10 km (6 miles). The potential, for stratiform or unconformity-related metalliferous deposits must be considered. The rift as a whole remains, however, largely unexplored.

Jan 1, 1990

By G. M. Wilemon, J. G. Davis, R. G. Swanton, B. J. Scheiner

The US Bureau of Mines has conducted investigations on extracting phosphate values from wastes generated during the mining and beneficiation of phosphate matrix. These wastes may contain up to one third of the phosphate originally present in untreated ore. Samples of wastes were air-dried and leached using 93% sulfuric acid in the presence of methanol. Evidence for the formation of a calcium sulfate hemihydrate coating that hinders complete dissolution of phosphate is presented. Solid-liquid separations were enhanced when flocculation was effected using poly(ethylene oxide) (PEO) in conjunction with hydroxypropyl cellulose (HPC) or hydroxyethyl cellulose (HEC). A conceptual flowsheet for a proposed process using an acid-alcohol leaching technique is presented.

Jan 1, 1991

By J. A. Frew, G. I. Orrock, R. M. Glen

The zinc flotation circuit was sampled to provide sized information on its metallurgical performance. A good balance was obtained and the roughing, scavenging, cleaning and regrind sections were assessed. Substantial losses of sphalerite occurred in all sizes. The limitations were poor recovery in the cleaning section which resulted in substantial recycling of 15-30µm sphalerite and iron sulphides, and inability to float +38µm sphalerite in the roughers. Regrinding increased sphalerite recovery by 7% with no loss in grade. Liberation measurements enabled balances for six size fractions to be calculated and the role of liberation on the metallurgical performance was assessed.

Jan 1, 1993

By J. Donald Rimstidt, Jeanette K. Jerz

Acid mine drainage is a major environmental problem worldwide. A key to remediating this problem is understanding the rate and mechanisms of the complex, multistep pyrite oxidation reaction under geologically relevant conditions. Because many waste piles are not submerged, a large amount of pyrite oxidation actually occurs in air. We have designed a Barcroft-manometer reactor to measure the rate of pyrite oxidation in air as a function of relative humidity and oxygen partial pressure. The reactor consists of two chambers joined by a manometer. Each experiment occurs at constant temperature, initial oxygen partial pressure, and relative humidity, although these variable can be changed between runs. Oxygen consumption was measured and pyrite oxidation rates were calculated from those data. Initial data indicate that rate of pyrite oxidation by oxygen in humid air is much faster than the rate of oxidation by oxygen in solution. The rates determined by this study can be used to develop better remediation techniques for acidic mine waters.

Jan 1, 2000

By D. Tao

The presence of insoluble slimes in potash ore poses a serious processing problem to the potash industry. These insolubles must be removed prior to potash flotation because of their high adsorptive capacity for amines which are generally used as collectors in the subsequent sylvite flotation. This is usually accomplished by scrubbing of the ore in brine followed by hydrocyclone classification to separate slimes from the salt particles. Insoluble slimes that remain in the ore after the desliming procedure are depressed by reagents such as guar gum or starch during sylvite flotation. In this research, the feasibility of using GP clay binders to replace guar gum for potash flotation was investigated. Batch mechanical flotation tests were conducted with the potash samples provided by a leading potash company. It has been found that GP clay binders increased potash concentrate yield and recovery at the same product grade. Effects on potash flotation efficiency of flotation process parameters such as impeller rotation speed, slurry temperature, binder type, dosage and conditioning time have been investigated to establish the optimum conditions for flotation. Binder GP374G33 has been identified as the optimum substitute for guar gum as slime depressant in potash flotation.

Jan 1, 2008

By Robin J. Batterham, Dave J. Robinson

The most significant trend in flotation has been the ever-increasing scale of operations. There is, however, doubt that this ongoing trend is enough to maintain the economics against trends such as falling grades, increasing mining costs, pressure on water supply and demand, rising energy demands needed for mineral processing, and a focus on whole of life value and mine legacy issues. We comment on the ramifications of broader uptake of more sustainable mining for mineral processing methods and address the specific question of whether recent progress in in-place recovery will lead to a timely breakthrough. The answer proposed is that this is possible in the next 10 to 20 years, but in the meantime the focus is just as likely to be on removal of waste (beneficiation) much earlier in circuits. Either way, mineral processing and flotation as we know it will change significantly. 

By Julian Boldy

The discovery of the Delbridge massive sulfide deposit in the Noranda district of Quebec resulted from an appreciation of the significance of a mercury leakage haloas a lithochemical pathfinder to blind ore, coupled to its location relative to a geologically inferred ore-bearing horizon within complex volcanic stratigraphy. Systematic sampling of microfractures present in outcrops delineated a diagnostic anomaly, drawing attention to an area considered prospective for buried ore. The massive sulfide deposit was subsequently found to be blind and topped at the 107-m (350-ft) level. This case history is presented in the context of its time and was the first volcanogenic ore deposit to be discovered utilizing mercury as a pathfinder in the Canadian Precambrian. The case history also illustrates that the practical application of an innovative technique coupled to a new geological interpretation can result in success, even on a property that was centrally located in a mining district and had undergone intensive exploration efforts over a 38-year period.

Jan 1, 1991

By E. Turner

In a joint exercise, the European Commission, (led by DG Enterprise), the EU Member States, the various sectors of the Extractive Industry, and WWF have developed a set of Sustainable Development Indicators specific to the non-energy extractive industries. Of equal significance, a Voluntary Scheme for publicly reporting the data has been created. This paper presents these indicators at the company level and explains the role of companies and trade federations in establishing the reporting process. This has been achieved in just 18 months and the paper identifies 6 Success Factors, which have made this possible. It is believed this is the first Scheme of its kind to be put into place and to have begun operation. It is a model for co-operation between government, the NGO sector and industry. The first set of data, based on the reference year 2001, has been gathered. The SD performances of the European Minerals Industry will be publicly reported on for the first time, on the basis of these 2001 data by industry sub-sector. The Member State level Indicators will follow to complete the picture.

Jan 1, 2003

By V. I. Ryaboy, V. A. Luknitsky, V. V. Zuyev

The action has been studied of three types of reagents used as intensifiers in grinding copper-molybdenum, sulphide-sheelite, polymetallic and other types of ores, namely N-donor, dispersant, and surface-acting agents. It has been proved that, depending on the type of ore treated, the C (N-donor) and C-170 (dispersant) reagents increase the yield of the principal size fraction of 0.074mm by 8-16% (relative). Consequently, the specific mill capacity improves by 13-21 %. The C and C-170 reagents activate the subsequent flotation stage and are thus beneficial to the mineral recovery. The surface-acting reagents affect the mineral grinding process to a lesser extent. The intensifying action of the reagents is attributed to the effective crushing energy decrease (lower crack-resistance factor) or else to the slime-dispersing effect of the reagents. The pilot-plant test results for the C reagents are given. Both C and C170 reagents are commercially produced and recommended for use at a number of concentrators in Russia, Uzbekistan and Kazakhstan.

Jan 1, 1995

By Jack E. Thompson

Thank you Tom and JM for that nice introduction. The remarks I am about to make rely on a large way on comments made by Barrick's Chief Counsel, Patrick Garver, to an internal meeting of Barrick's senior staff. I plagiarized so much from his notes that I thought that I should provide attribution. I did get his consent to borrow so freely. What I have done is take his general comments and used my conversations with CEO's and other participants in the industry to enhance the message with concrete examples that underscore the points I wish to make. What you are about to hear is my personal view – I am not speaking as a representative of any company. With that introduction, now would be a good time to give you the main theme of my talk: The SEC should change its rule making to a more public cooperative approach. If that were to happen the SEC would avoid some of the harm it has been doing to the companies in this sector and the very shareholders it seeks to protect.

Jan 1, 2003

By Robert E. Carver

Opaline clays from central and eastern Georgia are widely used as industrial and domestic absorbants, principally as insecticide carrier and animal litter. The clays are classified as fuller's earth, although they &e somewhat atypical of the group, since opal (cristobolite) is commonly the dominant clay-sized mineral. A preliminary investigation of absorption characteristics indicated that water vapor absorption (264 days) is' related to opal content as determined by x-ray diffraction peak height ratios. Ethylene glycol vapor absorption is related to montmorillonite content. Contact absorption of water is complexly related to surface absorption, porosity, opal content and montmorillonite content, and may be as great as 112% of the original sample weight. The most absorbent clays are highly porous (to 65%) and contain both montmorillonite and opal.

Jan 1, 1972

By Klaus Schönert

Experimental investigations of single particle and interparticle breakage show that the microprocess in mills demands an energy input between 1 J/g and 10 J/g, if particles below 100 pm have to be comminuted. A system analysis of grinding media and roller mills is given in respect to the energy supply to the microprocess and the influence of the back stream caused by the compression of the material inside the active volume. The back stream diminishes the probability for capturing the particles in very fine grinding processes. Some possibilities are discussed how to solve this problem.

Jan 1, 1989

By P. S. Parobeck, T. F. Tomb, R. S. Ondry

From October 1980 through August 1982, surveys were conducted on 19 longwall mining operations to obtain data relative to respirable dust levels associated with particular longwall operations and occupations, to make recommendations for enhancing dust control, and, where applicable, to evaluate the effectiveness of new technology implemented to control dust. The paper summarizes the data collected during these surveys and, where possible, draws conclusions and discusses actions that can be utilized to reduce exposures to respirable coal mine dust on longwall mining operations.

Jan 1, 1987

By R. L. Grayson

Conventional mine safety wisdom states that "the most efficient mines are also the safest." Since the 1980s, small mines (and contractors) have been targeted as the most dangerous because of their fatality records. However, statistical analysis of West Virginia safety and production data from 1993 indicated that, when considering the correlation between accident severity and tons mined per employee-hour worked, the most efficient mines were, with the exception of very small mines, not the safest operations. This paper presents the results of an extended analysis of West Virginia mine safety using 1993 and 1996 data and concludes with the method used to suggest current priorities for focusing interventions.

Jan 1, 2000

By Andrzej Wala, Waclaw Dziurzynski, Janusz Tracz

Recent advancements in computer hardware have led to the development of new ventilation planning software for PC's. These programs now can be run more quickly and can display their outputs with graphical techniques. Only a few of the existing programs have the capability to display the output data graphically on plotters. Graphical presentation of ventilation simulation data is essential for quick and sure comparisons of alternative analyses. Recently a noticeable growth has occurred in the application of graphics for display and interpretation of the data that have been developed by simulation procedures. The process of mine ventilation network analyses used for planning and design can benefit from this development. The authors describe and present graphics-assisted software that has been developed to work with a mine ventilation simulation program. This software has some of the following features: - graphic editor on screen, - graphical display of output data on screen (EGA, VGA), - graphical display on plotter or printer, - scaling capability (desired part of the entire schematic can be displayed), and - such values as flow, pressure loss, gas concentration for branches, and pressure and elevation at junctions can be presented as labels.

Jan 1, 1991