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By William Gleason

"It has been more than 10 years since Montana Resources’ copper/molybdenum mine has had a lost-time injury at its site in Butte, MT. With more than 350 employees and an average production of about 15.5 Mt/a (17 million stpy), which includes 29.5 kt (65 million lbs) of copper and 4 kt (9 million lbs) of molybdenum, the mine’s journey to a decade of exemplary safety is an impressive feat that has required hard work, commitment and, most of all, leadership from every level of the operation.It has not always been an easy journey, nor has it been one without scrapes and bumps along the way, but it is one that has produced stellar results. Mike McGivern, vice president of human resources, and Pete Steilman, safety manager at the mine, spoke with Mining Engineering about how the operation transformed from a site that was accustomed to collecting citations for safety violations to one that is now collecting awards for its safety record.Simply put, Montana Resources has made safety a value and the people its top priority.The operations faced many predictable challenges in 2003, when the mine was being brought back online after three years of sitting in care-and-maintenance status. It had been shuttered in 2000 because of low commodity prices and high operating costs, and, in the three years that the mine was idled, the equipment became dilapidated, and some of it was no longer in compliance. Less than half of the workforce returned to the site for the restart, and the team was challenged with getting the gears turning again to produce copper and molybdenum. But the most daunting challenge of all of was keeping the workforce safe during the transition.In the first few years of operation the mine racked up citations from the U.S. Mine Safety and Health Administration (MSHA) at an alarming pace, so much so that in May 2006, Montana Resources received a letter from the MSHA District Office informing the company that the operation was being placed on the Potential Pattern of Violations list due to its excessive citation history and high rate of significant and substantial citations. It was clear that something significant had to be done to change the course of action at the mine."

Oct 1, 2019

By R. Owen, T. Canty, C. Marks

The industrial vision system provides on-line 2D particle size analysis for aggregate slurries in both the overflow and underflow of hydrocyclones. This paper covers required vision system features allowing CCD cameras to function in the harsh environment of a mine milling area. The study conducted demonstrates the system’s capacity to obtain particle size distributions for controlling hydrocyclonic separators. The particle size distribution is obtained within seconds and immediately updated to allow for process adjustments. Results are then provided as a graphical computer generated display or output as a 4-20mA current loop for process control. The primary use of the vision system is in classifying particles in cyclone overflows which are often a few microns in size. Typical size information for actual mine slurry samples are presented and possible control schemes discussed.

Jan 1, 2002

By M. L. Harris, J. Organiscak, S. Klima, I. E. Perera

"The Pittsburgh Mining Research Division of the U.S. National Institute for Occupational Safety and Health (NIOSH) conducted underground evaluations in an attempt to quantify respirable rock dust generation when using untreated rock dust and rock dust treated with an anticaking additive. Using personal dust monitors, these evaluations measured respirable rock dust levels arising from a flinger-type application of rock dust on rib and roof surfaces. Rock dust with a majority of the respirable component removed was also applied in NIOSH’s Bruceton Experimental Mine using a bantam duster. The respirable dust measurements obtained downwind from both of these tests are presented and discussed. This testing did not measure miners’ exposure to respirable coal mine dust under acceptable mining practices, but indicates the need for effective continuous administrative controls to be exercised when rock dusting to minimize the measured amount of rock dust in the sampling device IntroductionTwo recent regulations have modified operators’ rock dusting schedules in order to meet compliance standards. First, the 80 percent incombustible requirement in intake entries has increased both on-section and out by the- section rock dusting. Secondly, the recent change to the respirable dust regulation has increased the number of respirable dust samples taken per sampling cycle. Previously, when only five samples were needed bimonthly, rock dusting could be scheduled to not interfere with the respirable dust sampling schedule.The significant number of samples now required under new regulations, combined with the need to maintain 80 percent total incombustible content in active mining areas, require the schedules for respirable dust sampling and rock dusting to overlap. Although rock dust is considered a nuisance dust in relation to U.S. Mine Safety and Health Administration (MSHA) sampling, these overlapping schedules raise concerns about the amount of rock dust that potentially is included in the sample. Additionally, the respirable dust maximum was lowered from 2.0 mg/m3 to 1.5 mg/m3 effective Aug. 1, 2016, increasing concern that rock dust contamination may be an issue (MSHA, 2016). Currently, the acceptable practice is to apply administrative controls such as keeping the miners upwind during rock dust application, or to schedule rock dusting during a maintenance shift when the number of miners present is lower."

Jan 5, 2017

By P. L. Crouse, S. J. Lubbe, M. J. Kabangu

A selective extraction and separation of zirconium by solvent extraction with 1-octanol is proposed. The process is based on the dissolution of the metal basic carbonates in hydrochloric acid in the presence of potassium fluoride, using 1-octanol as extractant. The effect of several process parameters, including hydrochloric acid and potassium fluoride concentrations, reaction time, and phase ratio between the aqueous and the organic phase was investigated. Zirconium is enriched in the organic phase. The best extraction and separation results were obtained with the basic carbonate dissolved in 10% hydrochloric acid and 1.5 M potassium fluoride. The optimum reaction time was 15 min with an organic to aqueous phase ratio of 2:1. Based on the selectivity of zirconium over hafnium in the organic phase, a McCabe-Thiele diagram was constructed. A near complete stripping of zirconium from the organic phase was achieved using a 3 M sulphuric acid solution. Additional studies are required in order to determine the reaction mechanism and the chemical speciation of the current investigation.

By Ralph W. M. Lai

The liquid membrane separation process was first patented in 1968 for separating hydrocarbons.(1-4) This stimulated many researchers to join in the area of separating organic compounds. l Since then, its applications have been extended to the removal of contaminants from waste water,(12-33) encapsulation of enzymes and/or microorganisms for reaction and/or separation, (24-28) oxygenation of blood (artificial lung),(19) removal of toxins from blood (artificial kidney)(26,20) and metal extraction.(31-63) This paper discusses the possible process schemes for using liquid membranes to separate and concentrate copper ion from its acidic leaching solution.

Jan 1, 1982

By F. Harold Weber

On July 13, 1967 the San Bernardino County Planning Commission approved publicly a request by American Smelting and Refining Company for a zone variance to conduct a silver mining and milling operation in the Calico district, southern California, Coincidentally, on July 14 the U.S. Treasury halted its sales of silver, and the U.S. free market price quoted rose immediately from $1.30 to $1.77 per ounce. In its request to the commission Asarco stated that about 13,500 to 15,000 tons of rock would be moved daily by surface mining, including 7,000 tons of ore. The ore would be crushed to minus three-quarters inches and the silver recovered "by a chemical process." The grade of the ore was not given, but the company said that it might also recover barite as a byproduct, The operation would employ 150-160 people. Additional activity in the district includes exploration programs by Superior Oil Company and Calico Silver Mines, Ltd. History and production: In retrospect, as the price of silver began to rise in 1961 from 91 cents an ounce, and as Asarco began its exploration program in late 1964, a new era for an old bonanza silver district would seem to have begun. The Calico district has been mined for silver only on a very, very small scale since 1882 to 1896, when an estimated $12 to $20 million (perhaps 15 to 20 million troy ounces) of that metal was produced from the 50-odd mines of the district and vicinity. These mines include the Silver King, Oriental, Waterloo, Garfield, Odessa and Waterman (which is about 8 miles west of the district). Much smaller-valued amounts of barite, gold, lead, and copper also have been produced from the ore deposits of the district; and from 1884 to 1907 the region yielded about $9 million worth of borate minerals.

Jan 1, 1967

By Michael B. Gilbert

The Woodbury L-73 Tunnel involved the design and construction of a 96-inch tunnel driven through 8,080 lf of very difficult ground conditions. Anticipated ground and groundwater conditions consisted of potentially flowing silty sand with cobbles and boulders, mixed face of sand and sandstone and full face of the St. Peter Sandstone. Actual conditions were similar, although the quantities did change from bid quantities. This paper presents the approach used for development of the GBR regarding risk management. The means of arriving at a fair compensation for variances from the baseline values to address the actual encountered tunneling behavior of the soil, boulder count and its effect on production rates are presented.

Jan 1, 2008

By James Wm. White

Today a large number of open pit mines use computer-based mine management systems to automatically assign haul trucks, track equipment, and manage information. Now advances in digital communications allow the use of these systems in underground operations. Underground mine management systems help maximize production by providing impressive gains in areas such as equipment and manpower utilization, draw point equalization in block caving operations, preventive maintenance, and safety. Current systems use allocated or "locked" train and LHD dispatching. While allocated dis-patching rarely optimizes open pit production, it offers an efficient mode of operation underground where options are more limited.

Jan 1, 1996

By C. R. Stephan

There are a large number of facilities throughout the world which handle coal, such as preparation plants. Many other facilities use coal as a fuel, such as cement and lime factories. Although coal can be handled safely and can be an efficient fuel, there are explosion hazards which are accentuated as the particle size is reduced. Particle sizes of coal which can fuel a propagating explosion occur within thermal dryers, cyclones, baghouses, pulverized-fuel systems, grinding mills, and other process or conveyance equipment. This paper discusses how explosions can occur within these facilities.

Jan 1, 1998

By U. B. Kodukula

Attempts are made to evaluate the feasibility of using a water-injection cyclone for the concentration of iron ore fines. The separation characteristics of clay fines, containing large amounts of alumina and silica, from the iron values are discussed. The effects of critical variables, such as injection water rate, truncated cone diameter, spigot opening and vortex finder diameter, on the performance of a water-injection cyclone in terms of iron, alumina and silica grades; iron recoveries; and alumina and silica rejections are discussed. A set of 16 full-factorial experiments (24) was carried out to gain an understanding of the individual and interaction effects of the variables. The results indicate that classifying iron ore fines containing 63.0% iron, 2.5% alumina and 3.5% silica through a water-injection cyclone can produce concentrates with iron grades greater than 66.0% and alumina and silica contents less than 1.5% and 2.0%, respectively, at different study conditions. The achievable iron recovery values are greater than 88%, and alumina and silica rejections are more than 80% and 50%, respectively, within the specific study conditions. While the truncated cone diameter, injection water rate and spigot diameter influences the alumina rejection to a considerable extent, it is mostly influenced by the vortex finder diameter. The iron recovery and silica rejection values are mostly influenced by spigot diameter and truncated cone diameter. The effect of injection water on the concentration characteristics depend on the prevalent truncated cone diameter and spigot diameter conditions.

Jan 1, 2008

By Linda J. Dahl

The U.S. Department of the Interior, Bureau of Mines is developing a process to selectively extract manganese from oxide ores as part of its in situ leach mining research program. The Bureau is conducting site characterization studies of two manganiferous iron-formation deposits which include: drill core, regional stratigraphic relationships from the existing geologic database, ore body geometry, geologic structure, hydrologic conditions, proximity of ore minerals to the leach fluid paths, surface subsidence potential, and data collected from laboratory leaching experiments. This information is being used to evaluate the technical, environmental, and economic feasibility of in situ leach mining of manganese for these two deposits. This paper will focus on the stratigraphy, mineralogy, ore textures, fractures, permeability, and porosity as they relate to in situ leach mining.

Jan 1, 1992

Editor’s note: As usual, the June issue features an industrial minerals review. And some thanks are in order. Thank you to the industrial minerals annual-review editor, to the technical committees chair and vice chairs and to the authors of the individual commodity profiles. Jim Norman of GeoTrans Inc. is the industrial minerals annual-review editor. Lucy McCartan, US Geological Survey, was the chair of the SME industrial minerals technical committees. She also served as the vice chair for agricultural minerals. Other technical committee vice chairs were: •Gary Tomaino, Specialty Minerals Inc., ceramics and refractory materials. •Srinivas (Vas) Veeramasuneni, US Gypsum, chemical raw materials. •William Langer, US Geological Survey, construction materials. •Vanessa Santos, Independent, fillers and pigments. •Richard Berg, Montana College of Mineral Science and Technology, specialty minerals. Their help makes possible this June industrial minerals issue. On behalf of the readers, the editors thank them.

Jan 1, 2002

By E. P. Deliac

The aim of this joint work between the French Coal Board and the Paris School of Mines is to be able to practically model the behaviour of a transverse drum cutting rock with picks. First a theoretical approach leads to the concept of cutting curves, giving forces and torque against penetration per drum revolution. Then experimental evidence, from full scale and reduced scale testing, validated and confirmed the theoretical shape of the curves. Finally practical applications are given, to improve the design or use of a shearer (or continuous miner). A micro-computer program is being developed to predict the cutting performances of a machine in certain conditions.

Jan 1, 1985

By E. D. Stephenson

As part of the British Steel Corporation?s development plan during the 1970?s, it was decided to concentrate its bulk steelmaking processes based on the BOS at 4 major Works with access to deepwater ore terminals, for the supply of high-grade imported ores. These 4 sites were at: - 1. Rarenscraig Works in Scotland where the ore terminal would be hilt at Hunterston on the west coast some 50 miles away. Bavenscraig was already an integrated Works but suffered from having to discharge ore 27 Glasgow tenxinus on the River Clyde, which could only accommodate vessels up to 25,000 tonnes. In the future, ore was to be unloaded at Runterston and shipped by a rail-link into Ravenscraig, The new ore terminal would have the potential to unload vessels up to 300,000 tonnes. - 2. Port Talbot Works in south Vales where the existing harbour was developed to discharge large ore carriers. This again was an existing Integrated Works and the benefits of the new harbour also applied to Llanwern Works which was another integrated Works some 50 dies to the east, which would now receive ore from Port Talbot.

Jan 1, 1980

By Todd Grounds, William R. Reed, VASU GANGRADE, Michael Shahan, Garron Ross, Kunal Singh

Roof bolter canopy air curtains (CACs) are gaining acceptance as a respirable dust control device that can provide roof bolter operators with protection from overexposure to respirable coal mine dust. Both lab and field studies on the effectiveness of roof bolter CACs have been published. Field studies have shown the effectiveness to be variable. However, in all previous field studies, none has been conducted when the roof bolting machine operates downwind of the continuous miner (CM)—a scenario for which the CAC was designed to provide respirable dust control. This study, performed by researchers from the National Institute for Occupational Safety and Health (NIOSH), was conducted to test a CAC on a roof bolter machine operating downwind of the CM. The results of testing demonstrated that the roof bolter CAC can effectively provide respirable dust protection for roof bolter operators with dust control efficiencies ranging from 11 to 40%.

Oct 14, 2020

By C. Y. Chen

Public Law 75-87, the Surface :mining Control and Reclamation Act of 1977 (SMCRA), Section 516(b) requires the underground coal mining operator to "adopt measures consistent with known technology in order to prevent subsidence causing material carnage to the extent technologically and economically feasible, maximize mine stability, and maintain the value and reasonably foreseeable use of such surface lands, except inn those instances where the mining technology used requires planned subsidence in a predictable and controlled manner . . .?. The Congress also directed the Secretary of the Interior to promulgate regulations to implement the law. As a result, the control of subsidence from underground coal mining to minimize surface damage has become the mandate of a Federal law. This paper discusses the mechanics of subsidence and the effects of subsidence on ground features and also summarizes some of the measures which have been used to minimize the possibility of damage to surface structures as a result of subsidence due to underground coal mining.

Jan 1, 1981

By John W. Motter

The Green Mountain Copper Prospect is an unusual stratiform base metal occurrence located in the California Foothills Copper-Zinc Belt. Mined for rich secondary oxide-carbonate ores since 1863, the first serious exploration of the primary ores was in the 1970's. Unlike typical volcanogenic deposits of the district, stratigraphy consists of greywackes overlain (?) or intruded by an intermediate to felsic volcanic unit. Shales and siltstones overlie the volcanic unit. Massive pyrrhotite, chalcopyrite and sphalerite occur at the top of the volcanic unit. Later intrusion and deformation metamorphosed the sequence and created a SW plunging anticline. Characteristic magnetic and electrical geophysical signatures are present and reviewed.

Jan 1, 1978

By N. C. Trivedi

Natural calcium carbonate, commonly known as limestone is an abundant resource pretty much worldwide. Calcium carbonate occurs naturally as the main constituent of chalk, limestone, and marble. One of the unique characteristics of this abundant mineral is its versatility. Major markets for calcium carbonate are: paper, plastics, caulks and sealants, carpet backing, paint, and food additives. This broad spectrum of consuming industries has warranted producers of this industrial mineral to be innovative and quality focused simply to meet the ever increasing demands for performance. This need for improving performance of calcium carbonate has led to the development of new sources of calcium carbonate, natural as well as synthetic.

Jan 1, 2002

By KOKOWSKI J., RUDZIŃSKI Ł.

The LUMINEOS network was established in 2013 to monitor mining-induced seismicity in Legnica-Głogów Copper District (LGCD), located in south-western Poland. Since the starting time, the network was improved and today consists of 17 seismometers and 10 accelerometers. Up to now, the strongest recorded earthquake in the region had Mw4.0. Both raw seismic data and earthquakes catalog for events recorded by the LUMINEOS network are fully open and available on the EPISODES platform (https://tcs.ah-epos.eu/#episode:LGCD). During the last 7 years, the network improvements gave us a possibility to increase location accuracy for shallow mining events. This accuracy is influenced by factors such as the configuration of seismic stations, noise level at seismic stations, and the influence of the velocity model. Here we encountered two main issues which are worth to discuss. The first one is the low detection threshold of two seismic stations and their significant impact on the location errors. The second one is the large uncertainty in the S-wave picking. Even though S-waves are not so clearly visible on seismograms, they are very helpful in the estimation of source location and strength of seismic events in the region. In our work, we present the history of LUMINEOS network and corresponding improvement on location accuracy as well as the influence of noisy stations on the error distribution and how it is connected with location results. We also investigate the effect of the S-wave phases and how they are related to the accuracy of the earthquakes locations in the network.

Apr 26, 2022

By Cheng Li, Yanlei Wang, Lingrui Kong, Jianxin Tang, Fang Yuan

Coal mined-out areas have a significant impact on mining safety and affect the pressure distributions of neighboring coal faces. The PFC3D software is used to study the goaf mechanical characteristics, and the core loading test verifies the rationality of the numerical simulation method. The results from the numerical modeling showed that the void ratio, particle size ratio, and particle size distribution of the rock particle sample (RPS) had a significantly remarkable influence on the compression deformation characteristics of the rock block. The parallel-bond tensile strength and parallel-bond cohesion had a notable impact on the compression deformation traits of the rock block only when the axial stress level was lower than 12 MPa. By contrast, when the axial stress exceeded 5 MPa, the effective modulus significantly influenced the compression deformation features. However, the stiffness ratio, loading rate, and parallel-bond friction angle had almost no effect on the compression deformation characteristics. Furthermore, when the stress level was less than 10 MPa, the stress–strain curves from the rock core samples’ numerical simulation and loading tests were approximately linear. In addition, the Pearson correlation coefficients of the stress–strain curves suggest that the goaf zone’s core numerical simulation results had a robust correlation with the loading test results. The findings of this study can serve as a reference for the field application of PFC3D software and safety assessments in goaves.

Jan 18, 2022