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By Robert A. Jankowski, George E. Niewiadomski

INTRODUCTION The utilization of longwall mining technology in the United States has steadily increased since the first longwall plow system was installed in 1952. At the errs of FY 1992, some 76 coal mines were employing longwall mining systems for coal extraction, and approximately 78 shearer and 3 plow faces are operating nationwide at any given time. Although the number of operating longwalls has remained relatively constant over the last five years, longwall production levels have increased significantly during this period. During the same timeframe, the number of continuous miner sections has decreased by 13 pct., from approximately 1438 in FY 1988 to less than 1250 in FY 1992. According to Mine Safety and Health Administration (MSHA) data, the average production of longwall sections increased from approximately 2400 tons per shift (tps) in FY 1988 to more than 3100 tps FY 1992. In fact, the average production has more than tripled since 1978, when it was only 850 tps. Approximately 25 pct. of operating longwalls are capable of producing in excess of 4000 tps. Longwall production currently accounts for nearly 36 percent of U.S. underground coal production, compared to 4 pct. in 1978. These improvements are attributed to improved longwall equipment and increased availability, larger longwall panels and automation. While longwalls are highly productive and offer other advantages, operations employing this method of mining continue to experience dust compliance problems more frequently than other mining system. Although dust levels have remained relatively unchanged over the past five years, averaging 1.6 mg/m3 and 1.9 mg/m3 based on results of operator and inspector sampling, respectively, during FY 1992, approximately 25 pct. of the operating longwalls were in noncompliance during any given bimonthly sampling cycle. Although modest gains in longwall dust control technology have been made, these have been overshadowed by significant increases in production rates. As more coal is mined, more dust is generated (Figure 1). Therefore, the increase in longwall productivity has meant that far more dust is being produced which must be controlled. [ ] In view of the current compliance record, any efforts to further increase longwall output, as has been forecasted, must be accompanied by: (1) the reduction of dust levels at existing operations through the proper installation and maintenance of suitable engineering dust controls; and (2) the advancement of dust control technology for today's and future longwalls that will enable all face personnel o work in an environment that is free of excessive levels of respirable coal mine dust. MSHA'S RESPIRABLE DUST CONTROL PROGRAM Since 1972, federal regulations have required each coal mine operator to continuously maintain the average concentration of respirable dust in the mine atmosphere during each shift in the active workings at or below 2.0 mg/m3 through the application of environmental dust control methods. The regulations provide for further reduction in the dust standard whenever the

Jan 1, 1993

By Raja V. Ramani

Discussion in this section of the Handbook is limited to the working environment of miners, the mine workers themselves, and the machines used in mining (Fig. 11.0.1). The contents emphasize personnel health and safety aspects and engineering design and control practices to ensure a productive health and safety environment. Reference is to the health and safety of the individual miners as well as to the safety of the working environment. This Handbook also contains references to health and safety regulations in Chapter 3.2 and environmental protection in Chapters 3.4 and 7.3.

Jan 1, 2008

By J. Gentry

Chemical grouting has been successfully used for over forty years to control the movement of groundwater in a wide variety of applications including tunnels, subway systems, sanitary sewers, mines and construction projects. This paper illustrates the versatility of chemical grouts by reviewing three projects where chemical grout was utilized to address some very difficult water control challenges. The featured product is acrylamide which can be used alone or in conjunction with other types of grout such as cementitious products. Acrylamide grout is injected as a two component product that will react and form an impermeable gel when the components combine. There are notable differences between the acrylamide based products and cementitious products. The most notable and significant difference is that acrylamide is a true solution grout that contains no particulates and has a viscosity of 1-2cps. This feature enables the acrylamide grout to penetrate very small geological features that other grouts could not penetrate and to seal small cracks and fissures where groundwater seepage is occurring. The product also has an adjustable gel set time from a few seconds to several hours which enables the operator to determine the product travel before it forms a gel. When properly applied the product has a half-life in the soil of 362 years (per testing by the US Department of Energy).

Feb 27, 2013

By B. K. Parekh, Z. Chen

INTRODUCTION The need for cleaning and recovery of fine (minus 28 mesh or 0.5 mm) coal fraction has increased in recent years. This results from realizing a substantial recovery of ultraclean coal from the waste stream improving overall Btu (heat) recovery, providing extra revenue for the coal industry. Also the potential of using the clean coal so obtained for making coal-water mixture which could replace oil. An additional benefit of recovery clean coal from the waste stream is reducing environmental concern of burning uncleaned coal and in waste disposal. Deashing of coal by physical beneficiation processes is limited by the degree to which ash components are liberated from coal. Conventional processes have been inefficient in terms of Btu recovery, for ultrafine coal. Chemical cleaning methods, which involves leaching of ash material from coal, have provided ultraclean coal at high Btu recoveries, are more costly than the physical cleaning methods. An advanced physical separation technique that appears to address the need discussed above is selective flocculation. This technique which has been successfully utilized in iron ore beneficiation offers the potential of processing fine and ultrafine coal to produce a clean fuel. OBJECTIVES The main objective of the present study is to investigate applicability of selective flocculation technique for recovery of clean coal product from the waste coal slurry supplied by the Peabody Coal co., from their three different coal preparation plants. It is also the objective of the program to conduct preliminary economic study of the selective flocculation process.

Jan 1, 2002

By C. E. McFarland, N. W. Kirshenbaum

Cortez Gold Mines is located about 75 miles southwest of Elko, NV. Activity in the mining district dates from 1862. The current operation developed from a 1963 joint venture of Webb Resources, The Bunker Hill Company, Vernon F. Taylor, Jr., and American Exploration & Mining Co. Three years later, the USGS discovered gold on the property following a regional geochemical survey. Drilling in 1966 and 1967 identified 3.4 million st of oxide ore grading 0.28 oz Au/st, and a 1700 st/day countercurrent decantation mill was commissioned in 1969. Heap leaching started in 1971 on low grade ore and continues to the present. The mill was shut down in 1976 following exhaustion of known oxide reserves. Mobile equipment was sold and the proceeds committed to local exploration. In 1980, a new plan of operations was developed starting with existing low grade and newly discovered mill ore. The mill resumed operations in 1981 and has been operating to date. A series of metallurgical innovations, culminating in the commissioning of a new fluid bed roaster in the summer of 1990, has enabled treatment of a series of increasingly refractory ores. Current partners in the venture are Kennecott Corporation, Vernon F. Taylor, Jr., and Placer Dome U.S. Inc., manager of the operation. Idaho Mining Corp. holds a 7.5% carried interest.

Jan 1, 1992

In its April 1991 issue, MINING ENGINEERING published a salary survey form asking for information relating to engineering and management jobs in the minerals industry. 1038 of these forms were filled out and returned, most of them being received in the magazine's offices at SME headquarters before the end of June 1991. An SME volunteer took on the task of tabulating and analyzing data from the forms, but the press of other business interfered with this work, and publication has been delayed until this issue of MINING ENGINEERING. Appreciation is extended to SME members who took the time to fill out and return the salary survey forms, and our apologies go to MINING ENGINEERING'S readers for the delay in publication. Of the total number of forms received, more than 97% were from SME members. The geographic distribution of the respondents closely mirrored that of SME membership as a whole, about 50% being from the Society's Western Region, 19% from the Central Region, and 23% from the Eastern Region. About 8% were from outside the US. Average salaries for each of the four geographic areas ranged between $55,000 and $60,000, with the highest average in Eastern Region (Fig. 1). Respondents were asked to answer a number of questions formulated to determine if there are significant differences in salaries based on the type of organization for which they work. As indicated by Table 1, salary averages at mining companies do not vary markedly with the size of the company: • Large companies, defined as those having more than $1 billion in annual sales, accounted for just over 16% of the returns. Their average salary was $61,840 per year.

Jan 1, 1992

When overburden depth exceeds economical recovery in openpit coal mines, the use of highwall mining systems has increasingly come into play. However, stability in the highwalls is always a major safety concern during such mining. The U.S. Mine Safety and Health Administration requires that highwall mining operators follow ground control plans that specify the pillar sizes necessary to prevent collapse that would threaten highwall stability.

Jan 1, 2006

By Hugh D. Olmstead

Typical operations necessary to develop oil and gas reservoirs are reviewed, including exploration, drilling, cementing, completion, work over, sand control, stimulation, enhanced recovery and production. The role of industrial minerals in these operations is described. Some of the opportunities and problems affecting increased use of industrial minerals in drilling and stimulation are discussed.

Jan 1, 1983

By T. D. MacQueen

Thank you Mr. Stevens. It's a pleasure for me to be speaking to this meeting of the Society of Mining Engineers of AIME this afternoon, and the Gypsum, Association is grateful for the invitation. A brief word about who we are: the Gypsum Association is the trade association for the gypsum industry - the manufacturers of gypsum board and lath a-d plaster. We have a membership of eight companies. These eight companies produce about 90% of the gypsum products manufactured in the United States ... closer to 94% actually. Our headquarters is in Evanston, Illinois. We have an east coast office in Washington, D.C. where the eastern manager handles technical and building code matters and maintains liaison between all of the government agencies and departments and our industry. We also have a west coast office in Los Angeles where our west coast representatives is heavily involved with the Uniform Building Code and ICBO. And then in the Evanston office our manager of technical and building code services, Herb Carlsen, bites his nails and loses his hair over these problems and various other projects that come in, such as conversion to metric and various other things. We also have a research associate at the National Bureau of Standards in Washington who is currently concentrating his efforts on the combustibility of building materials. His studies involve current testing methods, definitions, data analysis, and proposed new testing methods,.' It is anticipated that this program will lead to a better understanding of non-combustibility of building materials and systems. I mentioned that our members represent over 90% of gypsum products,' manufactured in the United States; it might be well to point out a couple of statistics about what that really means. According to the Bureau of Mines,

Jan 1, 1977

By C. Y. Chen

In order to put an end to the uneven environmental standards and enforcement established by various coal mining States in the United States, the Congress passed and the President signed the Surface Mining Control and Reclamation Act (Public Law 95-87 or the Act) on August 3, 1977. Within one year after passage, the Secretary of the Interior was directed to promulgate permanent program regulations implementing Title V provisions of the Act. These regulations were to form the basis for State regulatory programs under the Act and to allow States to assume primary regulatory responsibility. In order to implement the underground mining provision of the Act, the Secretary is directed in section 516(a) of the Act to promulgate rules, but ones which take into consideration the distinct differences between surface coal mining and underground coal mining. The regulations developed by the Secretary and promulgated on March 13, 1979, with respect to subsidence control, included (1) a subsidence control plan as part of the permitting process, (2) substantive provisions establishing performance standards for subsidence control, and (3) provisions providing for the prohibition of mining under perennial streams, impoundments larger than 20 acre feet, and certain public facilities and urban areas.

Jan 1, 1985

By Evan J. Owen, Virginia T. McLemore

of high specific gravity, resistant minerals that form from mechanical concentration by waves, currents, and winds in marginal-marine environments. These sediments are enriched in critical minerals such as titanium, zirconium, and REE. Cretaceous beach-placer sandstones are found in the Colorado Plateau of northwestern New Mexico. Originally discovered by airborne radiometric surveys for uranium in the 1950s, these beach-placer sandstones are being re-examined with modern methods as potential sources for critical minerals. Selected beach-placer sandstones have been sampled, mapped with ground radiometric surveys, and analyzed with whole-rock and trace element geochemical methods. Mineralogy is being determined with optical methods, XRD, and EMPA. Zircon, rutile, ilmenite, and monazite are the primary heavy minerals of interest found in the studied deposits. Initial results show that the sandstones contain up to 1.4% total REE, 29.4% TiO2, and an estimated 4.9% ZrO2. Chondrite-normalized REE diagrams show distinct light REE and minor heavy REE enrichment, as well as pronounced negative Eu anomalies for each deposit.

Feb 1, 2024

By Paul J. Henkels

Synthetic gypsum is the calcium sulfate co-product of a number of industrial processes. Synthetic gypsum utilization as an alternative to the naturally occurring mineral continues to grow in the gypsum industry. In particular, flue gas desulfurization (FGD) gypsum produced by the electrical utility industry has had a significant impact and a far-reaching effect on the gypsum wallboard manufacturing industry. This paper will discuss the various synthetic gypsum sources verses natural gypsum and highlight issues of use in gypsum wallboard and related products.

Jan 1, 1999

By R. H. Grau, C. D. Taylor, A. L. Martikainen

Utilization of belt air in underground coal mines has been discussed extensively during the last decade. The Final Report of the Technical Study Panel on the Utilization of Belt Air and the Composition and Fire Retardant Properties of Belt Materials in Underground Coal Mining formed by the Mine Improvement and New Emergency Response (MINER) Act of 2006 recommends research on leakage, use of booster fans, and escapeway safety. This paper discusses the role of ventilation modeling in evaluating primary escapeway pressurization in a three-entry development system to improve emergency escape in a coal mine using belt air. The intake entry of the National Institute for Occupational Safety and Health (NIOSH) Bruceton Experimental Mine was pressurized using a 1.1-m (42-in.) diameter, 37 kW (50 hp) fan. The work details air movement in the simulated three-entry system and the resulting leakage patterns. Three mine ventilation software packages were compared to analyze their performance in predicting the airflows and leakage conditions with different fan settings. NIOSH researchers found that the measurement results correlated well with the results of modeling.

Jan 1, 2010

By S. M. Pickering

Banks frequently manage large privately owned mineral land trust accounts for estate heirs. The bank has a fiduciary obligation to follow the “Prudent Man Rule”, which requires that trust properties be managed at least as well as a prudent and knowledgeable owner could. However, banks may not have internal staff proficient at mineral property values, lease contracts, royalties, mining practices, etc. This is an opportunity for experienced geologic consultants and certified minerals appraisers to provide needed help. Items valuable to Trust managers may include: 1. Marketing privately owned mineral trust lands to mining or oil & gas firms, assuring competitive offering prices and terms; 2. Negotiating favorable new mineral lease and purchase-option contracts; 3. Monitoring progress of mining, royalty payments, land reclamation, and environmental clean-up work; 4. Balancing future mining income with later industrial, commercial or housing development, timber harvest, etc.; 5. Assuring that Depletion Allowance tax advantage is taken for actual mine royalty payments, but not for annual non-mining lease (rental) income; 6. Appraising in-ground mineral value for bank audits, estate tax valuations, and equitable property division between heirs; and 7. Serving as expert witness, representing the legal interests of the bank, trusts, and the mineral heirs in litigation. Banks do welcome reliable advice which assists them in achieving the “Prudent Man Rule” and improving mineral income to their land Trust accounts.

Jan 1, 2002

By XUEWEN WANG, Changda Zhang, Huaguang Wang, Mingyu Wang, Bin Hu

The copper smelting process produces plenty of copper slag every year, which is a hazardous solid waste, but a secondary resource. In the present study, the extraction of copper, nickel, and cobalt from copper slag was investigated through the process of sulfation roasting–water leaching and the process of sulfation roasting–sulfate decomposition roasting–water leaching respectively. Compared with the process of sulfation roasting–water leaching, the process of sulfation roasting–sulfate decomposition roasting–water leaching is a better choice, which could not only get almost the same leaching of copper, nickel, and cobalt as the former process, but has a lower leaching of iron and aluminum. For the process of sulfation roasting–sulfate decomposition roasting–water leaching, the leaching of Cu, Ni, and Co reached up to 74.2%, 71.1%, and 69.6% respectively, under the optimal conditions including sulfation roasted with 80 wt% sulfuric acid addition at 200 °C for 60 min and sulfate decomposition roasted at 650 °C for 60 min, followed by water leached at 90 °C for 30min with a liquid–solid ratio of 2 ml/g. The leaching of Fe and Al was only 4.9% and 17.6%.

May 4, 2020

By O. M. S. Rodrigues

The kaolinite presence in bauxite ores increases caustic soda consumption during the digestion step in the Bayer process. Depending on the kaolinite content, the utilization of the ore in the Bayer process may be unfeasible. This investigation addressed the variables involved in kaolinite flotation through microflotation experiments in a Hallimond tube and zeta potential determinations. The tests were performed with a pure sample of kaolinite (96%). Five collectors were tested: Duomeen T (DT), cetyl pyridinium chloride (CPC), cetyltrimethylammonium bromide (CTAB), dodecylamine (DDA) and Flotigam EDA (EDA). Four of them performed well as collectors, at a concentration of 1x10-4 mol/L: CPC, CTAB, DDA and EDA. The kaolinite isoelectric point (IEP) was determined at pH = 4.6. The IEP was shifted towards higher pH values in the collectors? presence, indicating specific adsorption onto the mineral surface.

Jan 1, 2011

By Drummond Earley III

The U.S. Bureau of Mines is currently conducting laboratory experiments to study the reactions occurring during in situ leaching of oxide copper ores hosted by biotite-poor granite and biotite-rich granite porphyry. Detailed pre-leach and post-leach petrographic examinations of the rock samples are combined with the leach solution chemistry resulting from core leaching experiments to enable an evaluation of the various reactions which are responsible for the observed fluid chemistry. The information resulting from these laboratory studies is being utilized to support the design of the Bureau's ongoing field research project at the Santa Cruz deposit near Casa Grande, AZ. Atacamite and chrysocolla are the primary copper minerals present in this deposit, and both are readily soluble in the dilute 5% sulfuric acid solutions used in these experiments. In addition to the dissolution of copper minerals, biotite dissolution also occurs during the experiments, contributing K, Mg, Fe, and Al to the leach solution. The biotite dissolution appears to be non-stoichiometric, as it is progressively altered to vermiculite and finally, amorphous silica. While K, Mg, and Fe concentrations in solution steadily increase with time, Al quickly reaches a maximum, and then remains relatively constant for the remainder of the experiment. This suggests that Al saturation is achieved, and this Is supported by the presence of precipitated Al sulfate and aluminosillcate clay mineralization in the post-leach rock samples.

Jan 1, 1990

By J. G. Groppo

Laboratory settling and filtration testing was conducted on wet processed fly ash in order to determine the applicability of conventional dewatering techniques to reduce the moisture content prior to drying. Settling tests showed that acceptable clarity (<1.5 g/l suspended solids) could be achieved after as little as 6 minutes of settling. After settling to a consistency of 40 weight % solids, continuous laboratory vacuum filtration testing produced a cake containing below 20% moisture with throughput exceeding 150 lb/ft2/hr.

Jan 1, 1997

By P. C. Dagneau

QUEBEC CARTIER MINING COMPANY was incorporated in 1957 to explore and develop low grade iron are deposits in Northeastern Quebec. Four separate deposits were located and identified as being of ore quality and size to support commercial development. Said deposits were located at Lac Jeannine, Mount-Wright, Fire Lake and Mount-Reed. In 1970, in preparation for the replacement of the depleting Lac Jeannine are reserves, construction of an SS-mile railway extension was initiated, towards the newly selected mine site at Mount-Wright. This orebody was selected because the physical and chemical characteristics of the ore were very much similar to those of Lac Jeannine, as well as its huge reserves, estimated at more than one billion tons. In addition to the railroad extension, a mine, concentrator and related facilities were constructed and the new town of Fermont was created. Total investment for the Mount-Wright project exceeded $700 million and initial production commenced in 1976. Quebec Cartier is presently (1992) the leading producer and seller of iron ore in North America at 15,5 million tons and employs some 2,300 people.

Jan 1, 1993

By V. F. Hollister

The Ivanhoe district, Elko Co., Nevada, is located in the northern part of the Carlin trend of epithermal gold-deposits, but it differs from most mines in the belt in that Ivanhoe epithermal gold ores are found in 14 m.y. old Tertiary volcanic rocks as well as in the better known Paleozoic sediments. Within the Ivanhoe district U.S. Steel (USX Corp.) discovered and partly developed an epithermal gold deposit largely hosted by Tertiary rocks that, with a 167-hole program, was found to contain an open ended probable reserve of 4.0 million tons of heap leachable open pit oxide ore averaging .042 opt Au. An additional 4.0 m.t. of open pit sulfide ore averaging .048 opt Au were also developed. The U.S. Steel orebody was a blind discovery in that it just barely outcropped, and it was found by drilling through a premineral but barren cover of altered Tertiary volcanic rocks.

Jan 1, 1988