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By Celeste Powell

Liquid carbon dioxide can be used as a replacement for organic solvents in the extraction of anionic PGM complexes from an aqueous phase. This can be achieved only if highly carbon dioxide-soluble chelating agents are developed because conventional chelating agent-metal complexes, such as trioctylamine-gold chloride, are not soluble in liquid carbon dioxide (although trioctylamine is CO,-soluble). Our novel CO,-soluble chelating agents have a fluorinated tail and a conventional amine head group. Both the chelating agent and the chelating agent-metal complex are soluble at ambient temperature at pressures between 7-35 MPa. Equilibrium constants in the 105 range have been measured (in Freon 113, a low pressure screening liquid for carbon dioxide), indicating that these compounds will strongly bind the metal chloride. For example, 93% of Pt-chloride was extracted into Freon 113 using a 3.5:1I ratio of a double-tailed fluoroalkyl amine chelating:metal chloride. 88% recovery of Pt-chloride into liquid carbon dioxide was achieved using the same chelating agent at a 3.5:1 ratio.

Jan 1, 1999

By Evan J. Owen, Virginia T. McLemore

There are tens of thousands of inactive mine features in 274 mining districts in New Mexico (including coal, uranium, metals, and industrial minerals districts). However, many of these mines have not been inventoried or prioritized for reclamation. Many of these mines have existing mine wastes, generated during mineral production, which could have potential for critical minerals, especially since the actual mineral production was generally for precious and base metals and not critical minerals. The purpose of this project is to characterize and estimate the critical mineral endowment of mine wastes and “beta-test” USGS sampling procedures. This project is important to the state of New Mexico because critical mineral resources must be identified before land exchanges, withdrawals or other land use decisions are made by government officials. Future mining of mine wastes that potentially contain critical minerals will directly benefit the economy of New Mexico. Possible re-mining of mine wastes could clean up these sites and pay for reclamation. Furthermore, this project will include training of younger, professional geologists and students in economic and reclamation geology by the PIs.

Feb 1, 2024

By RALPH BALTES, AMIR EHSAN KIANFAR, FABIAN UTH, ELISABETH CLAUSEN

  Underground positioning and communication are essential technologies for the future of underground mining operations. In contrast to other positioning and communication technologies such as wireless local area network (WLAN) or radio frequency identification (RFID), ultra-wideband (UWB) radio technology provides significant benefits like accurate and robust positioning of mobile machine equipment, which is indispensable for future autonomous systems in underground mining processes, such as production, transportation and auxiliary operations. Among these technologies, UWB offers many advantages, including higher accuracy, robustness, resistance against noise and multipath effects, and low power consumption [1,2]. Underground automation and localization systems benefit from these advantages and use the technology to improve efficiency and safety. There are many studies being carried out on this technology to increase the results’ accuracy, energy sufficiency and more. Two robust UWB modules that were developed for underground positioning and collision avoidance with regard to human safety in underground mining operations are introduced. The measurement results of tests carried out in an underground mine are discussed as well to confirm the functionality of the system.

By Rennie B. Kaunda, Robert J. Sterrett

Some people in the mining-engineering field mistakenly believe that mine-water management primarily revolves around the treatment of mine waters that fail to meet applicable water-quality standards. While water-quality control is undoubtedly important, it represents only a fraction of what constitutes comprehensive site-wide, minewater management. A more holistic perspective recognizes that it also involves mine dewatering to maintain safe and workable conditions, securing sufficient water supply for operations, strategically handling surface water within and surrounding the openpit to prevent issues like flooding, developing robust post-closure plans to mitigate long-term environmental effects, and proactively minimizing any adverse impacts on local communities and ecosystems. This article provides a brief overview of topics that fall within the concepts of mine-water management. The focus is on openpit mines, as they are generally larger than underground mines. The management of mine water is highly dependent on local and regional climate such as tropical, desert or temperate climate. Each climatic setting has its own unique challenges, but there are also commonalities.

Jun 1, 2025

By MAHESH SHRIWAS, CHRISTOPHER PRITCHARD

Ventilation monitoring and control in mines are becoming an integral part of day-to-day activity for maintaining health and safety of miners. The authors evaluate potential real-time monitoring solutions for detecting and reducing diesel particulatematter, mine fires, and dust in situ, and examined the state-of-the-art use of ventilation monitoring and control in underground mines for detecting and reducing air contaminants to acceptable regulatory limit. Authors review relevant documents, including research papers, trade publications, and manufacturers’ website-based information, to identify research gaps. The authors also evaluate contemporary sensors (airflow, gas, dust, silica), control system and software technologies, data transport systems, Industrial Internet of Things, ventilation network simulators, and control devices to identify potential health and safety research gaps. In this study, examples of some mines from Canada, Australia, and the USA are included where ventilation monitoring and controls have been applied. Overall, this review identifies multiple challenges and research gaps in applying mine monitoring and control systems that could be the focus of future research, offering potential improvements to miner safety and health and financial benefits.

May 12, 2020

By J. G. Groppo

A series of performance studies have been conducted using counter-current column flotation to recover a marketable clean coal product from existing preparation plant fine waste streams. The test work was conducted at several preparation plant sites in Kentucky and Virginia and utilized a 0.15m (6 in.) I.D. column that was 5.79m (19 ft.) high. The refuse streams tested included both thickener feed and classifying cyclone overflow with a typical size distribution of 100 mesh X O. The percent solids of the column flotation feed varied from 1.5 to 15% while the ash content ranged from 30-60%. The concentrates produced contained 2-10% ash with BTU recoveries of nearly 90% using 0.12-1.25 kg/ton (0.25-2.5 lbs/ton) fuel oil and 0.12 kg/ton (0.25 lb/ton) MIBC. These results were consistent with or better than results obtained in preliminary laboratory scale column flotation evaluation. Test results from 7 different seams are discussed as well as scale-up relationships utilized to design a full scale installation presently in operation.

Jan 1, 1990

By M. Fan, A. Hobert, W. van Dyk

Low flotation recovery and selectivity have been long-standing problems in the treatment of most ultra-fine phosphate ores. This paper investigates the improved flotation of two ultra-fine Brazilian phosphate ores from Itafos’ Arraias project. These ores are predominantly composed of quartz, muscovite, apatite and a Ca-Al phosphate. As a result of fine phosphate dissemination and associated grinding requirements, column flotation was selected for the metallurgical test program to address the inherent limitations of fine particle flotation using conventional flotation cells. Accordingly, both benchtop Denver cell and laboratory column flotation tests were conducted to optimize their respective flotation responses. Improved flotation performance was achieved using column flotation as compared to benchtop mechanical flotation. In column flotation, a P2O5 concentrate grade of 30.5-31.0% was yielded at a flotation recovery of 83.7-85.1% for the 38x0µm generated ultrafines. The benefits of Eriez’ column flotation technology realized from this study include a higher degree of selectivity, increased recovery, and reduced collector dosage as compared to bench-scale mechanical flotation.

Mar 2, 2022

By Kefton H. Teague

Olivine was first described and named by Warner in 1790. It is an olive green to greenish gray colored magnesium-iron silicate containing a mixture, in solid solution, of fosterite (Mg2SiO4) and fayalite (Fe2SiO4). Ratios between fosterite and fayalite in olivine are somewhat variable, but in general olivine contains at least 85% fosterite. Specific gravity is variable also, depending on the ratios of fosterite to fayalite. As a rule it is in the 3.2 - 3.4 range. All commercial olivine is obtained from the rock dunite, the most basic member of the peridotite group. Dunites, in addition to being composed primarily of olivine, generally contain assessory pyroxenes and spinels (chromite and magnetite). Dunites', when altered by hydrothermal solutions or metamorphism, often contain alteration minerals such as talc, serpentine, chlorite, vermiculite and amphiboles. In the 1930's and 40's considerable research was conducted on olivine for use as a refractory, plant food raw material, magnesium source for metal, and a source for magnesium chemicals. This research met with only limited success.

Jan 1, 1977

By Thomas A. Earl

Strip mining of coal, and to a lesser extent limestone, gravel and other mineral deposits in the Appalachian region of the eastern United States has left many large and small areas of devastated land where mining predated reclamation requirements. In Pennsylvania alone, there are between 250,000 and 370,000 acres of strip-mined land 1,2/. A higher percentage, and a greater total acreage of land in Pennsylvania is in need of some form of reclamation than any other state, with the neighboring states of Ohio and Nest Virginia also having nearly the same magnitude of mining.2/ Recent legislation governing strip mining of coal proposed royalties to cover reclamation of such presently unusable land. However, in Pennsylvania and other states some progress has already been realized by utilizing abandoned strip mines and gravel pits for waste disposal sites. Given acceptable hydrogeologic settings, such use of these mined areas for landfilling has provided the incentive for ultimately restoring unreclaimed land to beneficial use, at no cost to the general public.

Jan 1, 1975

By A. E. Halim, J. F. Brune

Debate continues over whether barricading in refuge chambers is a good strategy to survive entrapment emergencies in underground coal mines, in particular fires and explosions. Unlike U.S. coal mines, Australian coal mines are not required to use refuge chambers and, instead, have adopted a strategy that focuses on instructing and training miners to self-escape to the surface. This paper analyzes the merits and problems of using refuge chambers or self-escape to the surface to manage emergencies in fires or explosions in an underground coal mine. We found that using refuge chambers may not be the best strategy during extensive fires or when multiple explosions occur. In these situations, mine rescuers are unlikely to be able to extract miners who are sheltered in chambers and, conversely, self-escape may save more lives than sheltering. Chances for successful self-escape are further improved by regular, externally assessed training such as the level 1 emergency exercises required in Queensland, Australia. These exercises put pressure on mine operators to ensure and maintain the effectiveness of their emergency management system.

By D. E. Hinkle

Past surface-mining operations in Appalachia primarily followed mountain con-tours. It is estimated that about 18,000 mi. of highwalls are exposed throughout Appalachia. An evaluation procedure for determining the secondary mining potential (SMP) of these highwalls has been proposed. Sixteen parameters affecting the SMP were isolated. These are grouped in four major categories: geologic conditions, existing infrastructure, site conditions, and environmental conditions. The parameters were then ranked by their impact on SMP and assigned weighting factors. A simple mathematical procedure yields an SMP number (0 < SMP < 100), which may then be used to compare alternative sites and technologies. Determination of limits and ranges while grouping data was aided by field visits to over 40 exposed highwalls in Eastern Kentucky. An interactive program has been developed to rapidly evaluate the SMP for pre-mined sites. The mathematical procedure estimates the relative potential (i.e., techno-logical feasibility) for remining for three predominant secondary mining methods: augering, Hi-wall mining, and underground mining. Other secondary mining methods are briefly reviewed and compared.

Jan 1, 1989

By Roberto Zaragoza

Historically, the control of flotation operations has been viewed by many as an art. Only recently has process measurement and control come to be viewed not as an ?art? but as a very complex and productive science. In recent years, process control applications to flotation plants have been established and already some gains have been reported for several industrial operations using individual stabilizing control loops including level, pulp flow, pulp density, reagent addition rate and pH (Paakinen, 1979; Hales, 1985). The use of process control computers combined with on-line x-ray florescence (XRF) in industrial flotation circuits has made the application of more sophisticated control techniques feasible in the mineral recovery process. In spite of the availability of reliable instrumentation in modern flotation plants, satisfactory control strategies are difficult to develop and implement. Extremely important factors such as changes in ore type, liberation characteristics, flotability, degree of oxidation on particle surfaces, and specific gravity constitute unmeasured disturbances to the process. Most current control systems cannot adapt specifically to such disturbances.

Jan 1, 1987

By Raymond K. Will

Computers are becoming increasingly valuable tools in the mining industry as a greater variety of appropriate hardware and software becomes available, combined with greater acceptance by management, Within a given time period an engineering staff can evaluate or design a project to much greater detail and higher accuracy by utilizing computers once suitable programs have been developed. We are all aware that throughout the world the decreasing grade of minerals coupled with increasing waste to ore ratios necessitate larger capacity, longer term mining operations and attendant higher capital costs. Computers can be of assistance in all stages of mineral exploitation, from geologic exploration through mine feasibility studies and design, to marketing and transportation. Because of the high speed with which data can be digested and manipulated by computers, preliminary information from any stage of investigation can be analyzed to assist in further guidance of that stage. By use of preliminary mine feasibility studies, financial forecasts and sensitivity analysis, even information from a far-removed phase such as marine transportation of the product, can help guide the exploration phase to a realistic target.

Jan 1, 1973

By J. D. Miller

Certain bituminous coals of recent geological age are known to contain a significant quantity of natural (fossil or subfossil) resin. Such resinous coals are found in the western U.S., particularly the Wasatch Plateau coal field in Utah. Some of the seams in this field contain approximately 5% resin which has been recovered by gravity and/or flotation processes since 1929. Resin concentrates thus produced are of low quality and are usually refined by solvent extraction and precipitation. The purified resins are of commercial importance, being used in the adhesive, varnish, enamel and ink industries, etc: Recently, an improved flotation technique has been developed which involves ozone conditioning to selectively float resin from such coals. In this flotation process, a concentrate product which contains 95% resin at a recovery of 80% can be obtained in a single stage from coal containing approximately 10% resin, whereas conventional flotation at a similar level of recovery produces a concentrate having a resin content of 30-40%. Economic analysis shows that the ozone flotation process has good potential for use by industry.

Jan 1, 1988

By W. J. Maloney, H. E. Tuneblom, A. J. Smith

The development of a large regional water supply in Southern West Virginia faced several hurdles. This paper deals with the design and construction of the intake shaft where a combination of cutting edge mechanical excavation technologies were utilized to produce a world class project.

Jan 1, 1999

By Jack V. Hill

A unique type of grinding mill liner has been developed by Waagner-Biro A.G. of Austria. This liner system, termed an angular spiral lining (.ESL), was, successfully tested by Magma Copper Company&apos;s San Manuel concentrator in both their 10 Ft x 10 Ft (3.05m x 3.05m) and 12 Ft, 6 In x 14 Ft (3.81m x 4.27m) grate discharge wet grinding ball mills. Magma Copper&apos;s savings in power and grinding balls justified conversion of more than half of their twenty-six ball mills to the ESL system.1,2 The ASL system was provided by the Capitol Castings Division of Midland Ross Corporation, the exclusive licensee for such conversions. Capitol Castings proposed the following as expected benefits from installation of an ASL system in an 18 Ft x 21 Ft (5.49m x 6.40m) overflow discharge wet grinding ball mill at the Pinto Valley Operation of Cities Service Company: "(a) Reduction of power consumption per ton of ore milled = 12%, (b) Increased throughput = 6%, (c) Reduction of ball consumption = 6%."

Jan 1, 1982

By Charles A. Bankston, John C. Rowley, Robert J. Hanold, Joseph W. Neudecker

The basic concepts and processes of soil and rock melting as applied to excavation technology are reviewed. The electrically heated, small diameter prototype penetrator development sequence is presented. Emphasis is placed on the different methods of handling the fluid rock and soil melts and their significance in providing new solutions in hole support and debris handling problems. The refractory materials requirements, penetrator life and electrical heater technology are presented. Consolidating penetrators, which form stable glass-lined holes in low density rocks and soils, require no debris removal and will find applications in horizontal holes for utilities, cables, and pipeline installations. Extruding penetrators are being developed to make holes in dense, hard rocks. Melt is conditioned into a variety of debris forms, i.e., glass rods, pellets or rock wool, selected to match appropriate debris handling systems. Unique use in drilling into very hot rock or magma for geothermal exploration or production wells is projected. Some of the results of laboratory and field tests of these devices are compared with theoretically derived operating performance. Coring-consolidating penetrators for geological sampling in alluvium are projected to larger diameter self-propelled and guided coring devices for prospecting along proposed tunnel alignments. Application to the melting of annular shafts for pipeline support piles in difficult conditions such as permafrost has been scoped. Conceptual design studies of large diameter tunneling equipment have indicated the system contributions and economic aspects of rock melting relative to material comminution, wall and roof support and materials handling.

Jan 1, 1974

By Louis W. Cope

In the early 1900s, vat leaching was a common process for treating gold ores. It was, however, labor intensive and was abandoned in the 1930s. Technology advances in recent years, though, have caused vat leaching to once again become a viable alternative in precious metal processing. At least three plants have been built. Others are being considered as alternatives to agitation and heap leaching. What is vat leaching? Vat leaching is a process in which ore is crushed and screened to a size of between 6 to 12 mm ( 0.25 to 0.5 in.) This crushed ore is placed in a large, boxlike container where an alkaline-cyanide solution is added and later removed. The process might be likened to indoor, controlled heap leaching. The ore does not require fine grinding in a ball mill. Therefore, capital and operating costs are lower than agitation treatment. But the extra handling causes costs to be slightly higher than heap leaching. If any amount of fines is present, the ore should be agglomerated.

Jan 1, 1991

By Patrick G. Hill

This paper discusses safety protocols for Kiewit Construction’s Level (3) project. The Level (3) project will cover a majority of the United States, and literally thousands of site operations will be conducted over a wide geographic area under challenging conditions; rivers, roads and other features, both from the surface and often for great and from boring pits. Developing a progressive safety plan for fast-track linear projects using micro-trenching and directional boring techniques requires significant investigation, planning and evaluation. Safety protocols for inner duct installation, to be accomplished with extensive use of directional boring is an essential part of the safety plan for network construction. In light of the shear volume of work and the geographical extent of this project, in many different types of terrain, this paper will identify approaches to safety applicable to fast-track linear projects, whether surface or underground-based. Establishing a safety culture into all aspects of this operation will improve productivity and cut unnecessary expenses. This new approach involves continual improvement and evaluation of hazard analyses, inspection procedures and training.

Jan 1, 1999

By Malcolm Wills

Boddington Gold Mine commenced operation in 1987 with an initial production of 3.0 Mt/y at a grade of 3.5 git. Head grade has reduced over the life of the mine and the major response to the drop in grade has been to increase mining rates and increase plant throughput. A capital expansion was carried out in 1996 increasing the throughput to 6.0 Mt/y and since that date tonnage has been increased without major capital expenditure. BGM's current mill throughput is 8.77 Mt/y ( 1999). In 1999 the combined basement plant and direct leach plant processed 8,770,055 tonnes to produce 233,507 ozs or 7.262882 tonnes of gold at an average head grade of 0.83 git. With grades of 0.83 git, and gold price at record lows, $US251.95loz in August 1999 or $A393.67loz it has been necessary to make and maintain major cost savings to remain profitable. Boddington Gold Mine has achieved this by a number of steps including a productivity study by outside consultants.

Jan 1, 2000