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By CASSANDRA L. HOEBBEL, Emily J. Haas, MARGARET E. RYAN

In recent years, there has been increasing interest in the role that individual factors play in health and safety (H&S) outcomes in the mining industry. Two surveys, one measuring self-reported routine safety performance and one measuring individual perceived competence in the non-routine knowledge, skills, and abilities (KSAs) critical to emergency response, were administered to two samples of mineworkers in separate research studies over a 2-year period (N=2,020 and 696, respectively). Eight demographic items were common to both surveys and their associations with each performance outcome were tested in response to a series of exploratory research questions.

Jan 9, 2022

Using a Mark IV surface force apparatus, adsorption of dodecylamine hydrochloride on mica has been studied at pH 5.7 in the presence and absence of octanol. With amine alone, the repulsive forces between mica surfaces are reduced due to charge neutralization and attractive hydrophobic force; however, the latter is of relatively short-range with its decay length less than 2 nm. In the presence of amine and octanol, the hydrophobic force becomes more significant, its decay length being extended up to 6.5 nm. The increased hydrophobicity in the presence of octanol is attributed to the co-adsorption of the neutral surfactant with dodecylamine, which increases the packing density of hydrocarbons on the mica surface. The increased hydrophobicity due to co-adsorption is reflected in the improved floatability of silica when using octanol as an extender.

Jan 1, 1993

By M. A. Evanto

Since the late 1970's, the Roof Control Division (RCD) of MSHA's Technical Support has been performing linear analyses for the enhancement of miners' safety. This remote sensing process uses Landsat data to predict areas of potentially hazardous ground conditions in underground mines. To date approximately 700 analyses have been completed by the RCD, with nearly 75 being performed with the current equipment, software and methodology which was updated in early 1995. While success is difficult to measure, requests for linear analyses continue to come from large and small mining companies which suggests the industry's acceptance of the process.

Jan 1, 1998

By D. F. Lillie

The milling plant of Bicroft Uranium Mines Limited has been in operation for a period of 2 years. During this time many changes, both physical and chemical, have been made in an effort to improve plant efficiency. Investigational work has been facilitated greatly by the fact that the Bicroft mill consists to a large extent of two parallel circuits; however, the number of inter-related variables is great, and it is difficult to measure, let alone control, all of them simultaneously. The Bicroft mill staff feel that much progress has been made, but there is much yet to be done and many questions still to be answered. The property of Bicroft Uranium Mines is located in Cardiff Township in the Highlands of Haliburton County, southeastern Ontario, some 140 miles northeast of the city of Toronto and 70 miles due north of Lake Ontario. The ore-bearing dikes are classed as mafic, non-segregated, syenite and granite pegmatites. Microline, microline perthite, quartz, uraninite, uranotharite, fluorite, titanite, cyrolite, calcite, pyrite, pyrrhotite and molybdenite as important accessories. The mill was designed for a nominal capacity of 1,000 tpd with all sections except grinding, leaching and clarification capable of 1,500 tons. Feed was entered to one mill unit on October 29, 1956 and to the second parallel line on November 13. The total feed rate was at 1,000 tpd on November 15. The first precipitate was produced on November 12. By August 1958 the average entry had been increased to 1,410 tpd without the installation of any additional major equipment. The overall recovery has been greater than 93,0 pet do several months, but a recovery of 92.5 pct appears to be most economical. Operating time for 8 months in 1958 has been 97.1 pet although all grinding mills were relined during this period.

Jan 1, 1959

By R. Pazhianur

Cathodic Protection using impressed current was employed to reduce the wear of the mill wall during ball mill grinding. Wear rates were determined from weight-loss measurements made on four, I-inch diameter, mild steel coupons installed flush with the interior surface of the mill wall. Grinding tests were conducted on quartz, pyrite and quartz-pyrite mixtures at pH values of 4.6, 7.1 and 9.2. Cathodic protection was shown to reduce mill wear by 40-60010. An examination of the coupon surfaces using scanning electron microscopy showed that cathodic protection greatly reduced pitting corrosion. The presence of a sulfide mineral, such as pyrite, was found to increase the wear rate significantly, possibly due to galvanic interactions. It is also found that the wear rate is significantly higher than the sum of abrasive wear and the corrosive wear, due to a synergistic effect.

Jan 1, 1996

By Dennis C. Parker

The Porters Creek clay is mined for its absorbent properties. The formation is part of the Upper Mississippi embayment and is recognized in Alabama, Mississippi, Tennessee, Kentucky, Illinois, and southeast Missouri. Major minerals in order of abundance are Montmorillonite, Quartz, Illite, Kaolinite, and Chlorite. Mining consists of open pit operation utilizing track loaders or scraper. The clay is dried or hardened in rotary kilns and crushed to size by roll crushers. The clay granules are sized and air classified prior to storage for shipment or packaging. Granules are sold for pet absorbents, oil absorbents, anti-skid material, fertilizer, and pesticide carriers.

Jan 1, 1979

By Nikhil Dhawan, Shrey Agrawal

India’s most extensive renewable energy expansion program targets 280 GW of solar energy by 2030. Due to the massive generation of photovoltaic waste (expected 34,600 T by 2030), stringent recycling effort to recover metal resources from endof- life PVs is required for resource recovery, circular economy, and subsequent reduction in the environmental impact. The present study investigates the recycling potential of end-of-life silicon solar modules. The feed characterization reveals that most of the values in PV modules are concentrated in the frame (pure Al), Si wafer (72–84% Si, 9–12% Al, and 0.13–0.71% Ag), and electrical connections (Cu wire coated with Sn). The Si and Ag values in the feed were beneficiated using water fluidization, and concentrate with 90% Si and 2% Ag was attained in the underflow concentrate. Ag values were recovered in the form of AgCl by leaching in nitric acid and precipitation. After the purification step, the residue containing 99% Si can be further utilized to fabricate Si wafer and Al-Si alloy. The preliminary cost estimations suggest that the proposed process is economically viable for the recycling of solar panels with the maximum value generated from the AgCl precipitate followed by Al panels and Si wafers.

Nov 14, 2022

By Karl C. Dean

To assist in the reduction of environmental degradation resulting from milling operations, the Bureau of Mines has developed, and successfully demonstrated, chemical, vegetative, and combined chemical-vegetative procedures for stabilizing milling wastes under varying environmental conditions. Costs of achieving reclamation using these stabilization procedures are compared with those of other physical and vegetative approaches. The Bureau's chemical-vegetative procedure for establishing vegetation directly on fine-sized wastes compares favorably with other stabilization processes that have been used.

Jan 1, 1972

By Fred C. Bond

The perennial subject of comminution is deserving of a fresh approach if one can be found. This is attempted here by directing attention primarily to principles rather than to theories. While theories attempt to explain how a certain process acts, principles delineate the laws which the action-must follow. Comminution may be defined as the progressive separation of particulate matter. At the present time this is accomplished commercially by applying energy in the form of compressive and, shearing forces. Such forces strain and distort the particles they contact. When-the applied stress locally exceeds the breaking strength at the weakest flaw in the particle, a crack tip forms. The surrounding strain energy flows to the crack tip, which rapidly extends through the particle as a break. The minute changes in shape and the resulting energy flow cause the failure of other highly stressed flaws, with the consequent formation of a progeny (1) of new smaller particles out of its destroyed progenitor. The applied mechanical energy is transformed into strain energy as the particle is distorted, and then into heat when it fails. Only a tiny fraction of the order of 1/1000 of the applied energy necessary for breakage appears as new surface energy in the product particles. The comminution problem is the relationship between, energy input and product particle size. Its solution is of great-economic importance,

Jan 1, 1961

By Koichi Nishimura

Japan's coal reserves are estimated at 8,583 million tons (according to the materials on X World Energy Conference,. 1976). Japan is a long island country in the shape of an elongated cashew nut whose top is pointing to the north and its lower tip is pointing to the west. And her major coal fields are located in the two extreme far parts of Hokkaido in the north and Kyushu in the south. On the other hand, Japan's major industrial center are located in the central part of the country far from either coal-producing areas. This fact places coal a great geographical disadvantage in comparison with petroleum whose refining bases are concentrated on the coastal regions virtually next to major industrial centers.

Jan 1, 1982

By Jr. Flynn

The filtration process has long been utilized in the mining industry and typically associated with processes where clear solutions are required. One definition of filtration states that it is utilized to affect a more complete separation of liquid and solid phases than is possible with settling alone. The development of Diatomaceous Earth filter aids has added a new dimension to filtration technology in the mining industry. It makes possible the filtration of slimes with almost perfect clarity, and at rates that become economical.

Jan 1, 1980

By M. Fig, B. Treffner, J. Brune, C. Strebinger, G. Bogin, D. Pardonner

"Methane gas explosions in a longwall coal mine can originate from in or around the gob and can seriously harm nearby workers and equipment. In order to fully understand the explosion flame and pressure wave propagation in the mine, it is important to investigate methane flame propagation in confined spaces as well as flame interaction with rock rubble and other mine structures. The latter can lead to enhanced turbulence causing high-speed deflagrations and/or detonations. Researchers ignited methane-air mixtures in horizontal, cylindrical reactors that contained inserts to simulate various gob characteristics. Rock surface topology and ignition location were investigated. Results show rock surface roughness increased fluid motion, thereby increasing methane flame front propagation velocity, overall pressure rise of the explosion, and time of pressure decay. Moving the point of ignition away from the open end of the reactor resulted in an increase in peak overpressure and an overall pressure rise of the explosion. Experiments were used to validate a computational fluid dynamics (CFD) combustion model that will be incorporated into a mine-scale explosion model to simulate and predict explosion hazards of large scale methane gas deflagrations in longwall coal mines. INTRODUCTION Coal mining is an integral part to our global society with coal-fired power plants providing about 40% of our global electricity [1]. A common method of extracting coal underground is by longwall mining. Researchers and investigative reports have found that explosive gas zones of methane-air mixtures can form along the longwall face and within the longwall gob, presenting an explosion risk to nearby workers and equipment [2]. In an explosion, the resulting flame and pressure wave presents a fatal traumatic injury hazard and can cause serious damage to equipment. In order to evaluate and mitigate the explosion risks in longwall coal mining, researchers at the Colorado School of Mines are developing a coupled CFD and combustion model of a longwall coal mine. The purpose of the model will be to better predict the explosion hazards under various mine conditions in order to build stronger prevention and mitigation strategies for miners."

Jan 1, 2018

By W. J. Wuest

The U.S. Bureau of Mines (USBM) has recently developed a rock mass classification system for evaluating the structural competency of bedded roof strata; the Coal Mine Roof Rating, or CMRR. When compiled with the companion Lotus 1-2-3 spreadsheet, which is simple to learn and use, CMRR data are a useful tool with applications to longwall gate road pillar design, safety hazard mapping, and artificial roof support analysis. This paper demonstrates these applications under actual conditions found in current U.S. mining operations.

Jan 1, 1995

By Rameshwar Sah, PK GHORUI, LR SINGH, SIVALINGARAJU BARISETTY, SHYAM YADAV

Fly ash is a by-product generated by the combustion of coal in thermal power plants. Its disposal is a major environmental concern for these power plants. Though a considerable part of fly ash is used in cement making and brick manufacturing, a substantial quantity remains unutilized. Bentonite is commonly used as binder in the micropelletization of process waste to attain the mechanical strength required for handling and transportation. The present paper deals with the partial replacement of bentonite with fly ash in the micropelletization process without affecting the quality of the micropellets. The mechanisms of both the binders are discussed. The bonding of particles by bentonite is a physical mechanism, while fly-ash bonding is a chemical mechanism. Silica and alumina are the major constituents present in fly ash along with lime. In the presence of water, the alumino-silicates and unhydrated lime present in fly ash undergo a pozzolanic reaction and form cementitious bonds, which hold the particles together. Use of fly ash as alternative binder for bentonite has cost benefits besides providing a better utilization option for fly ash.

By Vladislav Kecojevic

Both Canada and the United States are endowed with significant reserves of mineral resources. Mining industries in these two countries have a strong safety and health culture; skilled, dedicated and well-paid workforce; applications of state-of-the art technologies and high productivity, strict environmental requirements and social responsibility. Both countries are global leaders in safe, economic, productive, environmentally responsible and sustainable mining practices. Mining schools/ departments in Canada and the United States provide a strong and comprehensive education and training, hands-on learning experience, with support for internships and co-op opportunities to prepare graduates for careers not only nationally but also in the global mining industry. While there are many similarities in their industries and mining schools, there are also some differences. This article examines the contribution of mining to the economy, the political climate, the regulatory framework, the investment climate, environmental regulations, the language, the perception of mining, news and press coverage, and the academic landscape in both countries. Opinions, observations and perspectives shared in this article are of the author, and do not necessarily reflect the views, policies or positions of any organization, employer or affiliated group.

Nov 1, 2025

Stillwater Mining Company (SMC) has an extensive history with tunnel boring machines (TBM) at the Stillwater and East Boulder underground PGM mines in Montana. The most recent TBM used is for the Blitz Project, where a 5.5m (18ft) diameter main beam unit, commissioned in Q3 2012, is being utilized to drive a 6,975m (22,500 ft) ventilation and haulage level East of the Stillwater Mine for the Blitz expansion project. The assembly/commissioning of the TBM, institution of the planned diamond drilling program, application of ground control systems, and the current tunneling metrics will be covered.

Feb 23, 2014

By A. E. Jack Swanson, Brian P. Micke

INTRODUCTION Nevada Goldfields began underground mining development at the Kingston Project in September, 1986, followed by mill start-up in March, 1987. The first gold pour in April followed three years of preparatory work in establishing a North American operational base for the production of precious metals by Golconda Minerals N.L., an Australian mining firm. GENERAL CORPORATE BACKGROUND The Golconda Group of companies was established in early 1983 in Australia. It began operations by successfully retreating tailings at several old gold mining sites throughout Australia. With the limited reserves available for tailings retreatment, Golconda began to look toward the future by conducting a gold exploration program in Australia. However, the continued high price of gold in Australia had limited the possibilities of acquiring good properties at a reasonable cost and consideration was given to looking outside Australia in addition to Golconda's domestic exploration activities. North America was favored because of the proven potential for substantial gold deposits, the established infrastructure which would allow for rapid and cost-effective development of new projects and the advantages of similar political and economic climates. In mid-1984, Golconda established an office in California and began an extensive study of over 100 prospects throughout the United States. Two prospects were identified as a result of this study whch showed merit; one was located at Empire, Colorado and the other at Aurora, Nevada. Negotiations were then successfully undertaken to acquire these two properties. Golconda's U.S. offices were moved to Reno, Nevada in early 1985 to facilitate management of its projects. To operate and manage these projects, a small Canadian company listed on the Vancouver Stock Exchange, Cannon Minerals, was acquired by Golconda and renamed Nevada Goldfields Corporation. The current structure of the company is shown below in Figure 1. A private placement of 2,575,000 shares of common stock at US54.00 per share was arranged by Jacksons Limited of Australia in association with W.I. Carr (U.K.) Limited of London. This placement resulted in US510.3 million being available in May, 1986 for the acquisition and initial development of the Aurora and Empire projects. While the financing was underway, project planning commenced on both the Aurora and Empire projects. The Aurora project was selected as the one to be initially developed because of its relatively advanced stage of development. The

Jan 1, 1987

By Patricia Pride, Mike Robison, Jon Bergenthal, Wojciech Klecan

"The Lower and Middle River Des Peres (LMRDP) CSO Storage Tunnel is the largest single component of Metropolitan St. Louis Sewer District’s (MSD) CSO control system improvements planned to meet consent decree requirements for MSD’s Lemay Service Area. The 13.7-km (8.5-mile) long, deep, hard rock tunnel will have a finished diameter of 9.1 m (30 ft). Beginning at the Lemay Wastewater Treatment Plant (WWTP), the alignment follows the channelized River Des Peres to the outfall of the existing Forest Park tubes, as indicated in Fig. 1.The project includes three construction shafts, 34 intakes and a deep, cavern-style pump station located adjacent to the WWTP. The tunnel will be driven from the Defense Mapping shaft to the Macklind shaft. Another shaft is located near the midpoint at the tunnel in River Des Peres Park.The Forest Park intake, located at the upstream end of the tunnel just beyond the Macklind shaft, is a large, tangential vortex intake structure. With a peak flow rate of 170 m3/s (6,000 cfs), it will have a 6.1-m (20-ft) diameter dropshaft to transfer flow into the tunnel.The project includes another three large tangential vortex-flow intake structures with peak flow rates ranging from 28 to 44.5 m3/s (990 to 1,570 cfs). These large intakes are located at points where three large sewers (formerly creeks) enter the River Des Peres. Dropshaft diameters for these intakes range from 3 to 3.7 m (10 to 12 ft) in diameter. The 30 remaining intakes are smaller tangential vortex-style, with dropshafts in the range of 0.8 to 1.7 m (30 to 66 in.) in diameter.Each intake structure drops flow into a deaeration chamber constructed adjacent to the tunnel at tunnel depth. Intake tunnels transfer flow from the deaeration chambers to the main tunnel. Most of the intake tunnels are short. However, two are long. The Glaise Creek tunnel will extend 762 m (2,500 ft) from the main tunnel to the Alaska Park intake, while the Rock Creek tunnel will extend 823 m (2,700 ft) from the main tunnel to the Rock Creek intake. The dewatering pump station, located at the downstream end of the tunnel, will be built inside a large, horseshoe-shaped cavern with two access shafts. Excavation of the cavern and its access shafts will be performed by the tunnel contractor. Build-out of the dewatering pump station will be performed under separate contract."

Jun 1, 2019

By CHENCHEN SUN, GUOPING LUO, GUOCHENG ZHANG

Preparation of briquettes by adding CaF2 reagent into the Australian iron ore powder. The structure and morphology of iron ore briquettes during various reduction stages (i.e., Fe2O3→Fe3O4, Fe3O4→FeO, and FeO→Fe) were observed via an ore microscope and scanning electron microscopy. The results showed that CaF2 reacted with SiO2 to form CaO and SiF4 gas during the roasting process. The reduction swelling index decreased from 12.36 to 8.83% when the CaF2 content in the briquettes increased due to CaF2-mediated refinement of the hematite grains during the first stage of the reduction process. Lattice distortion resulting from the presence of Ca2+ in the FeO lattice during the second stage of the reduction process, coupled with an increase in the porosity of the iron ore briquettes and the formation of a low-melting-point slag phase, promoted the anisotropic growth of FeO lamellar crystals, which resulted in an increase in the reduction swelling index from 4.27 to 7.36%. During the third stage of the reduction process, the growth of iron whiskers was promoted by wüstite (FeO) lattice distortion caused by a solid solution of Ca2+ in the FeO lattice; the reduction swelling index increased from 15.61 to 24.72%, resulting in the catastrophic swelling of the iron ore briquettes.

May 27, 2021

By Connor Langford, Murray Gant, Ken Massé

For public organizations, preparing accurate project cost estimates is a critical component in capital project planning. Project delivery methods provide a structured approach to moving projects through the design and construction lifecycle, and typically use cost estimates as key inputs at each stage to determine if the project will advance. As design stages can occur years or even decades before construction contracts are awarded, estimates need to make reasonable assumptions about how the work may be executed (means and methods) as well as potential future market trends so that appropriate values for material pricing, labour costs, escalation, and owner’s costs can be included. This process is challenging enough during stable markets, as historic trends can often be misleading and require a suitable understanding of economic factors to use appropriately. When you mix in the market volatility that has been observed since 2020, developing accurate project cost estimates becomes even more challenging. In cases such as this, having a structured approach to cost estimating that includes an adequate risk-based reserves cannot be overstated as it provides the basis for ongoing project decisions. This paper explores some of the historic and more recent market trends that have impacted key aspects of project cost estimates for capital project planning. It also provides recommendations on how to develop cost estimates for infrastructure projects, with examples from Metro Vancouver, which plans for and delivers regional-scale services to 2.6 million residents. A brief commentary on the use of escalation clauses in contracts is also presented.

Jun 13, 2023