Search Documents

By Chris Joyce, Peter Ryan

Investigation of the occurrence and significance of acid drainage from mine sites in Australia has received a degree of attention in recent years. For contemporary and future projects, particularly those in hi1;1her rainfall areas, the focus on prediction and resolution of acid drainage issues is. likely to increase. This paper describes the preventative and remedial measures adopted at three metalliferous mines in northern Australia at which acid drainage was identified as a key issue with respect to project environmental management and rehabilitation. The thre case studies respectively comprise an active, ·1 recently decommissioned and an abandoned operatiou which was rehabilitated in the mid '80s.

Jan 1, 1991

By J. DeYoung

Weak demand for metals and consequent low metal prices resulted in continuation of the depressed state of US mineral exploration activity through 1983. Data collected by Resources for the Future Inc. and The Pennsylvania State University for a cooperative study on mineral exploration activity indicate that US exploration in 1983 fell by as much as 25% from 1982 levels. Precious metals remained the focus of most exploration efforts, as gold and silver prices remained attractive compared to base metals. Reports of 1983 domestic exploration and development activities in several industry journals indicates that about 85% to 90% of those projects were directed primarily at gold and silver. Gold exploration included work by several companies on Carlin- type disseminated gold deposits in Nevada, geological prospecting and drilling in the Wenatchee Gold Belt in Washington, and interest in lode and placer gold properties in California, especially by several small Canadian firms. Precious metals exploration projects were also reported in Alaska, Arizona, Colorado, Montana, New Mexico, Oregon, South Dakota, and Utah. There was also tome precious metal exploration activity in the eastern US. Development continued at the Ropes gold mine near Ishpeming, MI, and companies explored historic gold-producing areas in the Southeast. Some exploration for nonprecious metals took place last year. Stratabound copper-silver deposits were examined in western Montana, and US Borax continued exploring molybdenum resources in the Misty Fjords area in Alaska. Work on these projects during 1983 may have been stimulated by time limits on the availability of certain federal lands for exploration more than by projected improvements in metal markets. During 1983, several papers were published on mineral exploration strategies and the future of US exploration. David Watson of Raymond Kaiser Engineers, in a paper presented at the 1983 AMC Mining Convention, forecast increased exploration activity for gold and silver because of world economic conditions. He added that antimony, manganese, chromium, graphite, mercury, tantalum, tin, and barite are also likely targets based on their limited domestic reserve availability. He cited concern over reported subsidized mineral production by foreign producers and US regulatory and land-planning policies as retarding mineral exploration activity. Douglas Cook of Freeport Exploration Co., at the same meeting, presented a paper that showed that a 1950-75 period of vigorous exploration has been followed by a period where acquisition has replaced exploration as the predominant means of acquiring new mineral properties. At a December IIASA conference on "The Economics of Mineral Exploration," in Vienna, Austria, A. Rose and R. Eggert of The Pennsylvania State University pointed out that recent exploration decisions tend to rely more on evaluating production costs and comparing them with existing deposits, rather than on return of

Jan 5, 1984

By Hassan El-Shall, Abbas A. Zaman, Brij M. Moudgil

The addition of organic and inorganic dispersants to aqueous suspensions of heterogeneous particles (kaolin) was found to significantly affect the solubility of metal ions from kaolin particles and stability of the dispersion. In most of the industrial applications of kaolin, highly concentrated slurries of controlled stability and fluidity are required. The solubility of kaolin particles in terms of aluminum and silicon ions and its effect on the stability of the slurry was investigated. The main objectives of this study were (1) to study the effect of the extracted metals on the properties and performance of the slurry, (2) to understand the reaction mechanism of dissolution of metals from kaolin, and (3) to understand the interaction mechanism of dispersants with kaolin particles. The controlling variables were dispersant dosage, slurry pH, solids loading, and aging.

Jan 1, 2003

By Vljay K. Chhipa

Artificial intelligence is" an emerging technology in the field of computer application. Expert system have been developed to imitate human intelligence and reasoning process. Expert systems have much scope of application in the decision making process in mineral exploration as such decisions are highly subjective and expert opinions are very helpful. This paper presents a small expert system to analyze reasoning process in exploring for uranium deposits in sandstone.

Jan 1, 1989

By J. M. W. Mackenzie

Three major developments have dominated the recovery of gold from ores, viz; 1846 Elsner's studies of gold solubility in aerated alkaline cyanide solutions 1887 MacArthur and Forrest's process based on zinc precipitation 1980+ Large scale development of the CIP process The brevity of this list for a metal whose extractive metallurgy has been as widely studied as any metal reflects the fact that the chemistry of the gold recovery process, as opposed to the engineering has seen few significant breakthroughs in over a century of application. to The purpose of this paper is introduce a new chemistry for gold recovery which may, in the future, add significantly to the technology of gold recovery. This new chemistry is based guanidine functionality - (R2R2N) 2 C = N R2 on the In developing the use of the guanidine functionality for the recovery of gold as the aurocyanide anion from leach solutions and pulps, Henkel has, as its objective, the development of an effective gold selective ion exchange resin. As will be seen, the initial investigation of the properties of the guanidine functionality in the solvent form for gold recovery lead to some significant metallurgical developments of their own but, the foremost objective was, and remains, the development of a resin for gold recovery. As a part of this development project, Henkel has entered into association with Mintek, South Africa, and this ongoing association has the potential to develop RIP/RIS technology for the gold industry. More details on Henkel's gold recovery technology and Mintek's role in this programme are given in (1). an The application of ion exchange resins to gold recovery is not new and many reviews have been published on the advantages of this process, and on the current state of the art of gold recovery by ion exchange resins. (2)(3)(4) Widespread application of ion exchange resin based processes for gold recovery has, however, not occurred to date. Fleming and Cromberge (5), described some significant pilot plant RIP trials in South Africa and the partial success of these pilot plant trials held out the tantalising possibility of a breakthrough in gold recovery based on RIP technology. Despite this pioneering work, only two really significant applications of RIP technology for gold recovery exist today. These are the Golden Jubilee Plant in the Eastern Transvaal South Africa and the widespread, although in some respects technically backward, use of ion exchange for gold recovery in the former USSR. There are two main reasons for the current scarcity of RIP and RIS plants used for gold recovery. These are: 1. 2. The perceived problems of engineering RIP plants The lack of a resin having suitable chemistry for both gold loading and gold elution The problems of engineering RIP plants have been largely overcome in the last 25 years. Much of the development in RIP plant design took place in the uranium industry during the rapid expansion of that industry in the mid 1970's. In addition, the development of CIP engineering systems has lead to the development of in-pulp solid extractant based metallurgical plant designs which can, with limited modification, be adopted to RIP. The lack of a resin having suitable chemical properties has almost certainly been the main reason for RIP/RIS not being introduced into the gold industry over the past decade. Attempts to use RIP/RIS have focussed on either conventional we ak base or conventional strong base resins. The weak. base resins have the disadvantage that they

Jan 1, 1993

By Jean Paul Duterque, Morris J. V. Beattie

In many parts of the world, pyrite and arsenopyrite occur together in sulphide ores either as the only sulphide minerals or in conjunction with other valuable sulphides. It is desirable to produce separate concentrates of the various sulphide minerals, including pyrite and arsenopyrite, so that the contained desirable metals can be recovered economically. It is common, for instance, for gold in an ore containing both pyrite and arsenopyrite to be associated almost exclusively with the arsenopyrite. It is desirable in this instance to produce an arsenopyrite concentrate for gold recovery while rejecting the barren pyrite.

Jan 1, 1992

By W. W. Roberts

Key elements to the successful excavation and support of the Forest Glen Station and Tunnels for the Washington Area Metropolitan Transit Authority are discussed. Excavations encompassed a twin-vault station; 2339.3 m (7675 feet) of conventional drill and shoot tunnel; and 810.8 m (2660 feet) of mixed faced tunnel. The use of dewatering, boom type continuous miner and shotcrete in the mixed faced tunnel, along with hydraulic drills, bolts, and shotcrete in the rock tunnels and station proved to be effective methods.

Jan 1, 1983

By Ronald J. Doll, John Elkin, M. P. Evans

The application of "Alignment Free” right angle shaft mounted drive systems offers improved reliability and reduced costs for surface and underground belt convey- ors. Comparisons to conventional approaches will cover installation, operating, maintenance, and spares inventory cost savings. Various options for belt acceleration and load control on fixed and variable length (booster) belt conveyors will be reviewed for operating performance, reliability, and total cost. Lastly, a case study of a successfully operating installation will be highlighted.

Jan 1, 1996

By Marc E. Orman, Todd V. Ramey, Mark E. Smith

Heap leaching in certain parts of the world, such as Chile's Atacama Desert, brings unique design problems in the form of possible large differential settlements of the foundation soils due to the dissolution of salts. In northern Chile the soils often c?ntain very high concentrations of soluble salts (nitrates, potas­smm, magnesium, and common sodium). When a leak in the liner occurs, the escaping solution dissolves these salts and trig­gers differential settlement. If the settlement is great enough, the geomembrane tears, the leakage increases, triggering more dif­ferential settlement. The nitrate plants have experienced many occurrences of this phenomenon where a brine pond will under­go a sudden and complete loss of the impounded liquors. The authors present a simplified technique to quantify the differential settlement resulting from dissolution and provide a method which can be used to select a geomembrane with suit­able flexibility under axi-symmetric (multi-axial) load condi­tions to tolerate the predicted settlement.

Jan 1, 1996

By R. Mensah-Biney, M. T. Hepworth, K. J. Reid

The kinetics of gold-bromide loading onto activated carbon was investigated in a batch stirred reactor. Based on a second-order equation, the amount of gold adsorbed by the carbon was correlated with time. From a 30ºC solution containing 25 ppm Au and 0.8 g/L carbon, the rate constant for gold-bromide species onto activated carbon ranged from 0.27 x 10-3 to 1.2 x 10-3 (kg/t)-1 min-1. The equilibrium saturation capacity (Qe) was 36 ±3.0 kg/t from the same system. The rate of loading increased with increasing temperature and decreasing particle size, pH and solution gold concentration. The calculated activation energy (Ea) was 8.8 kcal/mole, significantly higher than those reported for physical adsorption. The equilibrium saturation capacity (Qe) increased with increasing concentration of gold in solution but was independent of other variables such as temperature, agitation speed, particle size and pH. These rate constants and equilibrium saturation capacity for the gold-bromide species are higher than those reported for the gold-cyanide systems.

Jan 1, 1998

By Michael Brittan

For several years, Independence Mining Co. (IMC) has routinely used oxygen fluid-bed roasting to pre-oxidize refractory gold ores ahead of conventional carbon-in-leach (CIL) processing. Oxygen serves jointly as the fluidizing medium and the combustion gas. This technology has proven to be reliable, environmentally sound and cost-effective. IMC is a subsidiary of the Minorco group. The company operates the Jerritt Canyon (a joint venture with FMC Gold) and Big Springs gold mines in the Independence mountain range north of Elko, NV. Ore bodies in the range contain characteristic refractory ore. It requires pre-oxidation ahead of conventional CIL processing. This article describes the technology developed specifically to treat these difficult ores.

Jan 1, 1995

By Otis M. Clarke

The 34th Forum on the Geology of Industrial Minerals gave members a chance to see the geology of various stone and ore deposits displayed graphically in quarry walls and also provided an opportunity to hear and see first-rate papers and posters on the geology of industrial minerals. Also, some field trips passed through areas of spectacular scenery. As a bonus, participants saw scenic mines, some of which are "pretty as a picture." Watercolor paintings prove it. At the Oklahoma Forum, the writer displayed a number of paintings of mines and other landscapes seen during previous Forum trips. These paintings and this brief article are part of a crusade to prove that some mines and geologic vistas are scenic wonders and belong in our visual heritage. It is a plea to save some of our best geologic exposures for future geologists, tourists, and artists.

Jan 1, 1999

By R. C. Ford

The advent of solvent extraction-electrowinning (SX-EW) technology for recovery of copper from low grade oxide ores has extended the operational lives of many historic mines in the western United States, and made many other orebodies economically viable worldwide. Many of these operations are mature and face closure within the next decade, depending on market conditions. Closure of a large copper heap leach operation has not been undertaken, and differs in some important chemical respects from closure of gold leach pads. Challenges for closure include prediction of solution chemistry and draindown characteristics, determining the benefit of cover placement in semi-arid climates and evaluation of solution management strategies once the economics of copper recovery are no longer favorable. This paper discusses issues pertinent to copper heap closure in semi-arid and arid climates, and strategies for their management.

Jan 1, 2000

By P. C. O. Chukabarah

Many aerodynamic and thermodynamic properties (such as temperature, pressure, velocity and density) vary widely, and in random spatial and temporal manner for a given underground mine environment. Such variabilities are seldom evaluated statistically, even though the relevant theories and principles are both available and feasible. The main purpose of this paper is to introduce the methodology for applying aerostatistics to the analysis of multiple fan systems in mine aerology/ventilation. Pertinent data were obtained from a small multi-level European coal mine. Results confirmed that aerostatistical methodologies are computationally more efficient. Being grounded in solid engineering statistical theories, they can be used to analyze networked parameters in mine environmental engineering.

Jan 1, 1995

By Anthony D. Songer, James E. Diekmann, Jarrett E. Carlson

Computer Aided Design (CAD) systems are currently recognized as a necessary tool for the management of projects. Currently, CAD is used for TBM and conveyor setups, concrete lift design and overall constructability reviews. Typically, such CAD models exist only in 2 dimensions. The advent of more powerful computers, enhanced CAD programs and after market animation packages provides tremendous potential to the Tunneling industry. In particular, effective application of these technologies enhances cost, time and quality in field operations.

Jan 1, 1997

By V. V. Ershov

Application of computers in the study of mineral deposits pursues two main objectives: 1. obtaining reliable information on the properties of the orebody; 2. providing graphic presentation of this information for its optimal use. These problems are successfully solved if, during preparation of graphic computer software, we apply modern mathematical methods. The present paper treats the problems of using geostatistics for graphic modelling of deposits by means of graphic computers. It should be noted that in this field geostatistical methods may be used for: a) indices evaluation in the nodes of regular grid, or in given blocks, by means of kriging, for its designated purpose; b) for evaluation of accuracy of interpolation methods, traditionally used in computer graphics, and not being optimal.

Jan 1, 1986

By T. Cohen

Technological innovation in the minerals industry must be driven by the need to improve performance according to social, as well as environmental, safety, efficiency and production criteria. This paper outlines the possibilities and rationale for incorporating constructive technology assessment into technology research and development within the CSIRO Minerals Down Under National Research Flagship (MDU). The paper develops a process of Social License in Design that attempts to address the future social challenges and opportunities of a technology during development by utilising forecasting techniques and accounting for the perspectives and values of decision makers and likely stakeholders. Interviews with senior technologists and social scientists within MDU reveal the institutional context into which the Social License in Design process is to be situated and highlight key factors that may inhibit or enhance its uptake.

Jan 1, 2011

Everyone knows the importance of careful handling of explosives. Even so, the point is on occasion all too graphically driven home. Witness the recent blast at a Utah explosives plant that killed five people. Part three of this series on explosives discusses transportation, storage, handling, and destruction. Federal, state, and sometimes local regulations govern the many steps involved in transporting, storing, and handling explosive materials. Regulations minimize personnel exposure to hazardous material and insure that the explosives remain stable and usable.

Jan 9, 1981

By A. MacG. Robertson

Where weak rock zones are encountered in the slopes of an open pit, they may control pit wall stability. Back analysis of slopes involving failure through weak rock enables an estimate to be made of the weak rock strength. A system of consistent rock mass classification is described which enables the weak rock mass material to be described and classified from drill hole core. Correlation with back analysis determined strength allows strength estimates to be assigned to each rock mass classification.

Jan 1, 1988

By Michael G. Nelson, Sekhar Bhattacharyya

Between 1974 and 1977, a detailed study of coal pillar strength was conducted by the University of Utah at the Beehive mine in southeastern Utah. This study was funded by the U.S. Bureau of Mines, and included laboratory testing of coal samples, extensive field instrumentation and measurements, and finite element analyses based on the laboratory results. Recently, a similar analysis of the laboratory results and mine design geometry was completed using the LAMODEL program developed by NIOSH. The results of this analysis were close to the data collected in the field. This study allows comparison with the earlier finite-element analysis, and illustrates the utility of the LAMODEL software suite.

Jan 1, 2005