Search Documents

By J. D. Carson

A 0.60 km2 (150 acre) wetland was reclaimed by Agrico Mining Company as part of a 1.48 km2 (366 acre) reclamation program in southwest Polk County, Florida approved by the Florida Department of Natural Resources. The upland portion of the area provides watershed for the wetland site which overflows into the flood plain of Payne Creek. Construction of the wetland was designed to provide conditions favorable for a diversity of habitats, as well as retention time for surface runoff waters. A variety of revegetation methods, including innoculation with muck from unmined wetland depressions, have produced encouraging results with both woody and herbaceous species.

Jan 1, 1983

By Joseph E. Schiller

As part of the Bureau of Mines research on identification of asbestos fibers, a method was discovered for removing asbestos fibers from water. This report describes this process and its theory of operation. The surface charge of amphibole minerals in potable water was found to be negative, and in common with most other silicate minerals, the isoelectric point of amphibole asbestos fibers lies in the pH range 4 to 6. Magnesia is one of the rare oxides with a high isoelectric point of about 11. The surface of magnesium oxide will, therefore, be positively charged in water at pH 6 to 6, while the electric charge an. amphibole asbestos fibers is negative. Because of the electrical attraction of these oppositely charged solids, it was possible to remove negatively charged asbestos fibers from water by percolating water that contained suspended-asbestos through a porous bed of magnesium oxide particles. A bed of 100/200-mesh MgO was added to a glass tube with a cotton plug. Aqusous suspensions of 1 to 10 ppm cummingtonite asbestos (amosite), crocidolite, and chrysotile were percolated through this porous plug of MgO. Even though chrysotile is positively charged below pH 11, MgO is an effective filter medium for removing it. The highly basic MgO appears to cause the chrysotile to flocculate and attach to particles within the bed. Scanning electron photomicrographs indicated that essentially complete removal of the fibers from water was accomplished. Other materials tested as contact filter media and found to be ineffective or only partially effective were sand, calcite, carbon, diatomaceous earth, and cellulose. Acidic alumina collected amphibole fibers but not chrysotile fibers.

Jan 1, 1980

By William M. Phillips

This paper will concern the processing of kaolin clays from the sedimentary deposits of Georgia and South Carolina, While the major processing steps will be touched on briefly, emphasis will be given to the dewatering of the clay-water slurries (slips) formed in the processing of kaolin clays The dewatering steps discussed will include gravity settling, centrifugal dewatering, vacuum filtration, and thermal dryings Of these dewatering steps particular attention will be given to vacuum filtration and the variables affecting filtration of these kaolin clays.

Jan 1, 1962

By Clément F. Bernier

One of the chief sources of the world's supply of asbestos lies in a belt of ultrabasic rocks which runs northeastward through an area called the Eastern Townships, south of the St. Lawrence River in the Province of Québec. The productive portion of this belt extends from the town of Asbestos in the south, for a distance of some 9,5 km to beyond the village of East-Broughton. The first discovery of asbestos in this region was made in 1874. Only crude fibre was produced until 1888 when the first mill was erected near the town of Black Lake. Since the inception of the industry, almost 100 years ago, no less than 100 different compa¬nies have been formed and 46 different mines have been operated. There are presently 5 active companies in the area providing direct employment for 4100 workers, down from 6000 during the seventies.

Jan 1, 1984

By Z. Yanni, W. Xuan, Z. Jingyu, D. Jun

"In order to conserve the coal resources, many coal mines which have been mined begin to re-mine. Re-mining face is of complicated circumstances and coal spontaneous combustion is unknown, so experiments are designed to study the characteristics of multiple oxidized coal samples. The investigation into the oxidation of coal is conducive to the safe mining of the coal seam groups and thick coal seams. The non-caking coal is collected as coal samples. The raw coal sample with initial oxidation and the sample after second oxidation and third oxidation are obtained after a certain treatment of the coal. The temperature-programmed system, and proximate and ultimate analysis are adopted to compare the releases of gaseous products of spontaneous combustion characteristic parameters of the multiple oxidized coal sample. With the increase of oxidation times, experimental results indicate that the oxygen consumption rate, the release rate of carbon monoxide and the intensity of heat release are significantly decrease. The characteristic temperature dropped and the size of the pores in coal is smaller as well. INTRODUCTION China accounts for 13% of global coal resources [1-2]. In recent years, more and more coal mines begin to re-mine in order to conserve resources. This production mode is to mine coal pillar left by last exploitation or unavailable for mining. In the process of slicing mining for coal seam groups or thick coal seams, the second or multiple oxidation due to the mining-induced effect, may take place in the goaf of the lower seam. So the spontaneous combustion is prone to occur in this area. The study on oxidation of coal is conducive to the safe mining of the coal seam groups and thick coal seams. Scholars [3-7] have discussed the workability of re-mining for coal mines, verify the feasibility of the existing mining technology for re-mining area, and set up the prevention measures of coal spontaneous combustion. But all these measures are only based on on-site observation data, instead of experiment on spontaneous combustion characteristic parameters of re-mining coal samples which have a great importance for early prediction and forecast. The authors aim at investigating the multiple-oxidated coal spontaneous combustion law, and perfecting the coal spontaneous combustion mechanism to provide a basis for the prediction and forecast."

Jan 1, 2015

By Stanley M. Jarrett

Gentlemen, I am pleased to address this gathering of engineers and operation managers representing a large and important segment of the metal and nonmetallic mining industry. Since you know from the printed program that the theme of my paper is the furthering of safety in open pit mines, perhaps you will have guessed that I will also comment upon the image created in the public mind by the industry's safety record and the potential consequences thereof in national health and safety legislation. Operators of surface mines have some cause to congratulate themselves on the basis of figures issued by the national safety council which show that lost-time accidents per-million-man-hours in surface mining (11.18), is lower than that of all other mining. Moreover, the accident frequency in surface mining is only slightly above the median accident rate for all American industry (8.87). That is a good record.

Jan 1, 1972

By R. E. Mason

Shotcrete has been used for approximately 20 years to facilitate tunnel excavation through poor ground. Early examples of such usage in North America include the recuperation of the Granduc Mines access tunnel in Northern British Columbia, and similar work performed in the Carley V. Porter and Big Walker Tunnels in the United States. Mining companies such as Craigmont Mines in B.C. and Hecla Mines have used shotcrete in their workings for the past ten years. Shotcrete is now a widely utilized fool in the mining and tunnel construction industries in North America, but the accumulated experience is too limited for many to fully appreciate the capability of shotcrete to control ground movements and to understand the limitations of this tool. It is common, for instance, to use shotcrete to "bridge the gap" between rock bolt-supported and steel-rib supported ground and to avoid the use of shotcrete in water-bearing ground. Shotcrete can, and has been, used economically and practically under most severe ground conditions.

Jan 1, 1976

By Cesar Carrasco, Heath Arvidson, Mark Forster

Block models built to represent the geology and rock characteristics of mineral deposits represent huge complex data sets, which form the basis of strategic and business planning, and public reporting of Mineral Resources and Mineral Reserves. Recent advances in cloud computing and database technology developed for the Internet of Things offer a different way of working with these critical data sets. Enabling a cloud based, open data structure with high performance data analytics capability presents a compelling improvement in governance and a democratization of ore body knowledge that can lead to automation use cases that support the digitalization of mining.

Jun 25, 2023

By Harley G. Pyles

Rotary Percussion drilling has shown great improvement over rotary drilling, when hard roof is encountered. In addition, Rotary Percussion drills have eliminated the need for air drills in many applications. Improved drilling rates have been achieved but roof bolting is still a bottleneck in many operations and the demand for further improvement will continue. Drilling rates beyond current performance is limited by the capabilities of existing drill steels and bits to resist increased horsepower input. The most apparent immediate solution to improved drilling is to increase the strength and rigidity of the drill steels. Drilling experience indicates that a l-1/2" diameter or 1-5/8" diameter hole can be drilled as rapidly or 'more rapidly than the standard 1-3/8" diameter hole. Greater torque and thrust capacities can be achieved through the use of larger O. D. and I. D, steels, however, this is only possible if the larger hole sizes can be made allowable. Large diameter anchorage shells can be made available at a slight extra cost.

Jan 1, 1965

By James J. Brady, Kenneth L. Faught, Chadi El Mohtar, Chaoshi Hu

"During construction of a 9.5-ft. diameter sanitary sewer tunnel, the City of Edmonton encountered a large pocket of flowing sand that flooded their TBM and caused significant surface subsidence, stopping further tunneling by the TBM through this zone. A unique collaborative effort ensued between the authors representing the city, consulting engineers and academic researchers to develop the optimal strategy for grouting the problematic soils. The site has a layer of very find sand between 20 and 30 ft. in depth with fines contents ranging from 5% to more than 40%. The collaboration extended from requesting additional site investigation efforts to shipping samples to the UT-Austin laboratories for grout testing plus ground and grouting characterization tests resulting in field recommendations for a full scale ground improvement program. New research information on the grouting of fine sands along with a collaborative framework for the design of in-situ grouting projects are the key topics presented. INTRODUCTION Encountering a large unexpected pocket of flowing sand with an open-faced TBM while excavating a tunnel below the groundwater table is never a good thing. This was certainly true for the City of Edmonton when one of their Lovat TBM’s became inundated by flowing sand while excavating the 9.5-ft. diameter Millwoods Double Barrel Replacement Tunnel in September 2013. However, since the City of Edmonton self-performed this work, a rare situation existed where the site could be investigated objectively, without the prejudice of contending parties selectively influencing how information was gathered and presented, to accurately examine site conditions with a goal of identifying the best remediation measures."

Jan 1, 2016

Western Energy Co.'s Rosebud mine in Colstrip, MT, has implemented innovative mining techniques in the past,* and following in that tradition, new techniques for overburden removal were recently introduced at the Montana coal mine. In April 1979, falling coal production left Western Energy in a bind. At that time the company was one of the first to implement a dozer/scraper stripping system for additional stripping capacity. This time around, however, the challenge was to eliminate spoil rehandle with a dragline while digging down 33 in. "Rehandle will increase 20% by going down an additional 3 m past the 24-m level," according to Bob Cope, mine supervisor for Western Energy. To cut this additional expense by eliminating the need to rehandle, Western now uses scrapers to bench down for the dragline. This system utilizes the flexibility of scrapers as earthmoving tools. Although scrapers were originally purchased to fill an immediate need for productive, low-cost overburden stripping, they are now benching and continue to optimize the overall effectiveness of existing draglines. According to the company, the draglines couldn't keep up with production requirements if they had to rehandle spoil material. Benching with the scrapers eliminates spoil rehandle. Western Energy expects to produce 10.6 Mt of coal this year from three active pits in the Rosebud mine. Western estimates that there are enough coal reserves at Rosebud to support a 40-50 year operation. The sub-biturninous coal has an energy value of 9.2-9.4 Mj, 0.87% sulfur, 8% ash, and 20% moisture. Pit A, approximately 610 m long and 45-55 m wide, is the mine's greatest producer. A Marion 8050 dragline with a 46-ms bucket digs 30-33 m to uncover the 7.3-m Rosebud coal seam. Here, the scrapers were put to work benching for the dragline. Long Construction Co., which operates the mine equipment for Western Energy, uses four Caterpillar 637 tandem-powered scrapers, two Cat 631s and two Terex TS-24s. The number and combination of scrapers actually used for benching periodically changes, depending on which ones are needed for topsoil removal and reclamation. Scrapers benched down about 9 m and removed nearly 2.3 Mm of over-burden at pit A. About 1 Mm was placed in a 9-m lift on top of the high-wall at the head of the pit. The scrapers built up one side of the lift first and then the other on successive passes to

Jan 2, 1981

By Raymond A. Bradbury

Martin County Coal Corporation operates three underground mines and two surface mines on Wolf Creek in Martin County near Inez, Ky. The original underground development was begun in March of 1970. The property being developed is leased from Pocahontas Land Corporation. The A. T. Massey Coal Company, whose offices are located in Richmond, Virginia, is the parent company and sales agent for Martin County Coal. Duke Power Company is the customer who will take all the production from the mines which ultimately are scheduled to produce 2,500,000 tons annually. The Norfolk and Western Railway Company built a 24-mile railroad into this huge reserve of low-sulfur steam coal. Four coal seams, all above drainage, are included in the lease. The Middle Coalburg and Stockton seams are being deep-mined now and it is in three mines that the diesel haulage equipment is used. Those of you who attended the AIME meeting in Birmingham last October or the Diesel Symposium in Pittsburgh in January of this year are familiar with the introduction of trackless diesel-powered haulage equipment into our Martin County mines. I made a presentation at each of those meetings which dealt with our first experience with Wagner Mining Equipment haulage units. These machines are sold exclusively by Lake Shore, Inc. whose offices are in Iron Mountain, Michigan.

Jan 1, 1973

By Terry D. Vandell

The purposes of this presentation are: (1) to discuss the actual as well as potential incidents that have caused and that could cause groundwater contamination at uranium in situ leach mining sites and (2) to discuss remedial actions and solutions that have been or that could be implemented in the future to stop or prevent serious groundwater contamination from in situ leach mining in Wyoming?s Powder River Basin. Open pit, underground, and existing and proposed in situ leach uranium mine sites in the Powder River Basin are shown in Figure 1. In situ leach mining or solution mining for extracting minerals in liquid form is a relatively new addition to the list of conventional mining methods currently used to extract uranium in Wyoming's Powder River Basin. Basically, the in situ leach mining method involves: (1) the injection of a leach solution lixiviant (an acidic or basic oxidizing solution) into a uranium-bearing ore body, via injection wells, to complex the contained uranium, (2) mobilization of the uranium complex from the host material via creation of a soluble complex salt, and (3) surface recovery of the solution bearing the uranium complex via production wells. Uranium is then separated from the leach solution by conventional milling unit operations (ion exchange).

Jan 1, 1981

By Hamid Maleki

Mine seismicity is influenced by the mechanical properties of both near-seam strata and overburden/underburden and the prudent selection of mining methods and mine layout designs, utilizing sitespecific structural setting of the mines. The importance of adequate data collection, monitoring, and prudent structural designs has long been recognized and utilized in many U.S. operations with adequate engineering resources. In this paper, two case studies of historic seismic events and contributing factors, in deep coal and trona mines with overburden thickness exceeding 1,500 ft, are reviewed using observations and analysis. By back analyzing the overburden response in a historic room-and-pillar coal mine, the overburden collapse mechanism associated with a 3.3 magnitude seismic event is reviewed as well as the need for improvements in designs including panel and barrier pillar widths. Similar high-order seismic events were also experienced in trona mines of the Green River Basin during 1990s, interrupting room-and-pillar mining and creating ground control concerns. Efforts to improve structural mine designs are described in this paper leading to stable and productive operations for decades following the high-order seismic events in both coal and trona case studies. These efforts included improving room-and-pillar extraction layouts and utilizing properly designed longwall mining techniques that were verified using long-term geotechnical instrumentation. The study mines are located on the Wasatch Plateau (WP), Utah and in the Green River Basin (GRB), Wyoming. More recently, in Utah’s East Mountain alone, Energy West Mining Company (EWMC) has extracted some 165 million tons of coal without any significant incidents. Overall, favorable geologic conditions and prudent mine layout designs are key elements to this successful experience in both single- and two-seam layouts. Utilization of conservatively designed longwall mining technique in the GRB has been geotechnically stable, using reported experience in 15 panels and monitoring results in the Northwest (NW) District with measurable longwallinduced seismicity being rare. These studies demonstrate a considerable amount of progress that has been made within the last four decades in the application of longwall mining technique, integrated monitoring, and analyses for the verification of structural designs in mines in the United States.

Jul 1, 2023

By M. Beale

Fuzzy logic and neural networks are new technologies being applied in many areas of engineering and business. While it is not always clear which kinds of problems are best suited to these technologies, and which problems are best approached with more standard methodologies, both fuzzy logic and neural networks appear to show great promise in the field of control systems. This paper demonstrates two advantages that these technologies offer: Easy controller design in the absence of a mathematical model of the plant to be controlled, and adaptive control capable of quickly responding to changes in the plant.

Jan 1, 1994

By R. W. O. Kersten

The shrinkage method of stoping with pillar support has been used at Agnes Gold Mine since mining commenced. Until recently, rock instability did not have any detrimental effect on safety or production. Presently sill pillars are failing not only on the current production levels, but also in shallower old worked-out areas. The incidence of failure raises the question as to whether the pillar dimensions are adequate at the current working depths and what their size should be at greater depths. The effect of pillar dimensions on the economics of the mining operation is of paramount importance because of the amount of ore that can be left unmined.

Jan 1, 1982

By Adolph V. Mitterer

International Minerals and Chemical Corporation operates one of six potash mines in the Carlsbad potash basin. More than 90 percent of America's potash is produced at Carlsbad and IMC accounts for about one-fifth of that amount, Since the Company began operations in 1941 it has mined nearly 50 million tons of ore. Of the two types of ore mined at Carlsbad the principal tonnage is sylvinite in which sylvite-potassium chloride-is the ore mineral. It is produced by IMC as well as by all other mines in the area, In addition to sylvinite IMC is the exclusive producer of langbeinite ore--potassium-magnesium sulfate. From its two ores, International produces a spectrum of 8 high-quality agricultural and industrial chemical products.

Jan 1, 1959

By Harold Rees

[This report supplements and brings up to date a paper prepared earlier this year for presentation at the Eleventh Pan American Railway Congress to be held in Mexico City, October 18 to 31, 1963. In order to acquaint the reader with the background of this project practically all of the first paper is included in the report.]

Jan 1, 1963

By George F. McKeregahan

Phosphate production of the Central Florida Phosphate District has been predominantly from the unique and lucrative Bone Valley Formation, with local and minor amounts coming from the underlying Hawthorn Formation. As the Bone Valley is depleted, replacement production will move progressively into areas of total Hawthorn Production. Significant changes in the characteristics and make-up of the deposit dictate required modifications in mining and beneficiation. Failure to tailor technology to fit the deposits of the future will result in vast "reserve" losses. In the Southern Extension of the Central District - two distinct "ore types" exist. These are presently referred to as the upper (high grade) zone and the lower (low grade) zone. The upper zone is somewhat similar to the Bone Valley Formation and will respond favorably to present beneficiacion practices. The lower zone is strikingly different and its response to conventional beneficiation is not acceptable. The major differences are in grain size distribution and mineralogical make-up of these grains. The Hawthorn differs from the Bone Valley by exhibiting lower grades, lower tonnage yield per acre foot, lower pebble percent of product, higher mining ratios, higher slimes (-150 mesh) content and deeper mining depths. Physical characteristic changes include more frequent occurrences of competent bands or lenses of "limerock" which are submarginal in value.

Jan 1, 1983

By X. Zhu, L. Chen, R. Guru, M. Peiravi, M. Mohanty, L. Ackah, B. Xu

"The overall goal of this study was to develop a suitable flowsheet to extract rare earth elements (REEs) from coal ash. Only the findings from the first part of this study is being reported at this time. A total of fourteen coal samples of different ranks were examined for REEs concentration. An anthracite coal sample, originating from Pennsylvania having more than 700 ppm (in the coal ash) was selected for the REE extraction tests. The experimental program completed so far included high temperature leaching using nitric acid, followed by the solvent extraction tests. A 4x2x2 experimental design was used to conduct a total of thirty two high temperature leaching tests by varying acid molarity (at 4 levels), solid content (at 2 level) and leaching time (at 2 level). The highest LREE (light REE) recovery of 90% and HREE (heavy REE) recovery of 94% were obtained from the most optimum leaching test condition while maintaining the impurity recovery to the leachate at less than 40%. Solvent extraction experiments were conducted to recover the REE’s from the above leachate solution using a variety of organic extractants including, TBP, Cyanex, D2EHPA and their combinations. D2EHPA was found to be the best extractant during this SX text series providing nearly 99% recovery of REEs. INTRODUCTION The demand for rare earth element and other strategic metals (REM) in the world is rapidly increasing due to their use in a variety of high technology applications. More than 100,000 tons of rare earth oxides (REO) are being used worldwide on an annual basis. However, we have less than 10% of the world reserve of rare earth element (REE) mineral deposits in the US. More than 60% of rare earth oxide (REO) was imported to the US from outside (mostly from China) in the year of 2013. However, China’s institution of export quota has significantly reduced the supply of REMs to the U.S. Hence, new ways of producing REM and/or finding substitutes for those metals for the high-tech applications need to be invented/discovered in a timely manner. Coal Combustion Byproducts (CCBs), which are discarded as waste materials in most cases, are known to contain REEs (in low concentration) that could be extracted using a suitable process flowsheet. This may be a worthwhile route to pursue considering the short supply of REMs and the abundance of coal ash in thousands of ash ponds in the US. On an annual basis, more than 110 million tons of Coal Combustion Byproducts (CCBs) are being produced while satisfying our nation’s need for electricity (ACAA, 2014). However, less than 50% of these CCBs are being successfully used in various applications and the remainder is being dumped as waste materials in the landfills and ash ponds."

Jan 1, 2017