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By William A. Gibson, Kenneth P. Neumann

In 1967, development of the Cyprus Thompson Creek molybdenum deposit began near Challis, ID. The first mining claims were staked on an intrusive rock out-crop. Exploration continued for 14 years. In 1978, the decision was made to develop the deposit. In Dec. 1980, approval was received for the environmental impact statement and facilities construction and waste rock removal began. By the middle of 1983, 126 Mt (139 million st) of rock had been removed and all facilities completed. Location The Thompson Creek project is located about 58 km (36 miles) southwest of Challis in Custer County, in south central Idaho. The mine and mill are situated between 2.2 and 2.6 km (7,217 and 8,530 ft) in elevation. The project is located in an isolated area. Surrounded by mountains, it is adjacent to the Sawtooth National Recreation Area. The Salmon river is 8 km (5 miles) south of the project. The project claim block is lo-

Jan 1, 1984

By Joseph D. Drew

Oregon Resources Corp. (ORC) has developed and permitted a new mining operation that incorporates a process design that will allow the unique paleo-beach placer deposits of southwestern Oregon to be extracted efficiently and economically, creating the only domestically mined source of a unique foundry grade chromite and specialty de-veining sand for precision casting. The operation will also provide an additional domestic source of garnet and zircon. Engineering design has been guided by the variable geology and mineralogy of the paleo-beach placer deposits as well as the need for a dry tailing scheme that resolves a lack of water resources at the placer locations and at the same time eliminates the need for slurry settling ponds, typical of paleo-beach placer operations in North America.

Jan 1, 2010

By Arif Emre Dursun, Ali Aras, Hakan Özşen

Specific energy (SE) is defined as the amount of work required to cut a unit volume of rock and is used to estimate the performance of excavation machines. Generally, the SE value is produced from full-scale or small-scale rock cutting tests. However, these tests require expensive equipment and experienced personnel, and the testing procedure is time consuming and impractical. Therefore, for estimation of SE, this study aimed to find a solution to estimate SE using rock mechanics test results and Bond work index values (BWi), which can be produced in a more practical, less time-consuming manner and with inexpensive test equipment. Small-scale rock cutting, rock mechanics and Bond work index tests were carried out on seven rock samples, which can be grouped into two different type of rocks: marble and travertine. In addition, the instantaneous cutting rates (ICR) of a selected roadheader were calculated using SE values. Rock mechanics tests performed in this study were uniaxial compressive strength (UCS), Brazilian tensile strength (BTS), ultrasonic velocity (Vp), Schmidt rebound hardness (RL), corrected point load index (Is(50)) and density (ρ). The simple regression method was used to estimate SE from rock properties and BWi. As a result of this simple regression, a significant and highest correlation was found between SE vs. UCS and Is(50). A good correlation was found between SE vs. BTS, RL and BWi values. A moderate correlation was found between SE vs. Vp and ρ.

Jul 28, 2021

By D. S. Choi

This paper presents the results of geomechanics work applied to the longwall operation. The mining method was successfully adapted to US mining conditions resulting in an improvement in safety and productivity. The paper deals with various geomechanics problems associated with geologic and mining conditions.

Jan 1, 1987

By Fathi Habashi

SELENIUM AND tellurium are by-products of electrolytic copper refining. Copper anodes contain 0.01-0.2 % Se and up to 0.04 % Te; during electrolysis these deposit as a slime at the bottom of the cell. Such slimes contain 2-15% Se and 0.5-8 % Te, as selenides and tellurides of gold, silver, and copper. The following compounds have been identified in the slimes: (Ag, Au)Te2, Ag2Se, Ag2Te, CuAgSe, Cu2Se, Cu2Te. Anodic slimes from copper electro¬lytic refining are a grayish black powder, minus 200 mesh. When this complex mixture is decomposed in an acid medium, elemental selenium and tellurium can be obtained, while in an alkaline medium, both metals go into solution. Acid leaching The slime is charged in acid digesters of 800-900 lb capacity, heated to 260°C with 78 % H2SO4, for 8-12 hr. During digestion the following reactions take place:

Jan 1, 1970

By Steve Kral

It is agreed in mining and regulatory circles that a safe and healthy working environment for underground miners is the major challenge for mine operators. Underground mine ventilation is complex. And it is becoming even more difficult as mines become larger, deeper and more complicated. At the Seventh US Mine Ventilaton Symposium, a group of mine ventilation experts from industry, government and academia attempted to solve some of the problems in ventilating underground mines. The meeting, sponsored by the Underground Ventilation Committee of SME and the University of Kentucky, was held in Lexington, KY June 5-7, 1995. Andrzej M. Wala, symposium chairman, commented that previous mine ventilation symposiums have focused mainly on work in North America. The 1995 symposium, however, broadened its borders to include several international papers. Of the 77 papers presented and bound into the Proceedings volume, 25 are from operations and research centers outside of the United States and Canada.

Jan 1, 1995

By J. E. Bevan

Once mining compromises the stability of a rock mass, the dangerous task of roof bolting begins. Many attempts have been made to automate this process, but there are still many refinements that need to be made. In the past, roof bolting modules were designed around the abilities of a human operator. Currently, researchers are taking a new approach that focuses on designing modules that can utilize bolting methods that are easily automated. A non-rotating anchor that is locked into position by a linear force (as opposed to a rotational force) was designed by researchers at the U.S. Bureau of Mines. Once the bolt is secured in the bolt-hole by the anchor, the bolt is tensioned and a collet is used to secure the other end of the bolt. This process replaces the traditional bolt-nut fastening method. This program is part of an effort at the U.S. Bureau of Mines to automate the coal mining process.

Jan 1, 1994

By S. J. Porter, M. T. McRae

The new tunnel at Genting Sempah is part of a privately funded infrastructure projectthat involves duplicating the existing highway extending from the Gombok Toll Plaza near Kuala Lumpur to Karak, in Malaysia. The 60 km long tollway includes an 800 m long, two-lane highway tunnel with excavated dimensions of 10.5 m wide by 8 m high. The majority of the tunnel extends through slightly to moderately weathered, moderately to highly jointed quartz porphyry. Excavation of the tunnel was performed using drill and blast methods and the primary tunnel support consists of rock dowels and shotcrete except for short sections adjacent to the portals where steel sets were utilized. A portion of the tunnel encountered sheared and altered material that was successfully supported using rock dowels and shotcrete. The final lining for the tunnel consists of mesh and fiber reinforced shotcrete. The flexible nature of the primary support and shotcrete final lining resulted in considerable cost savings and expedient construction methods.

Jan 1, 1997

By T. Naarttijärvi

The Fabian ore body near Malmberget, Sweden, has an ore reserve of 5 Mt of predominately low grade iron ore, containing 40-55% Fe. Mining began in 1971 with a new method called slot block caving. About 2 Mt were mined, but poor fragmentation resulted in too much secondary blasting. This decreased mucking efficiency to such an extent that the method was abandoned after only 40% of the ore volume had been mined. At this stage a large stope (180 x 30 x 100 m) had been excavated. Although the exposed area was quite large, no caving action occurred in the hanging wall or in the ceiling. LKAB decided in 1977 to introduce sublevel stoping using 105-mm-diam holes. This was the first time large diameter holes were used underground in Sweden. The method had been evaluated in collaboration with the University of Luleå (LuH), the Swedish Detonic Research Foundation (SveDeFo), and the Swedish Mining Research Foundation.

Jan 3, 1982

By AJIT SWAIN, SUNATI MOHANTY

The ability to predict the dewatering performance of an industrial hydrocyclone from a laboratory-model hydrocyclone is of great importance. In this study, laboratory-scale hydrocyclone experiments were conducted using silica sand samples at 10 percent solid concentration for dewatering with Mozley hydrocyclones with diameters of 2 in. and 4 in. The objective is to predict the design parameters for an industrial dewatering cyclone to achieve higher solid concentration in the underflow. A model was developed based on the Nageswararao hydrocyclone model with the help of a commercial simulator for a hydrocyclone operating at 100 t/h and 20 percent solid concentration to achieve 80 percent solid recovery at 45 percent solid concentration in the underflow.

Mar 1, 2023

By Jia-Shyan Shiau, Chung-Ken Ho

An uneven gas distribution through the burden layers inside a blast furnace (BF) results in abnormal gas resistance or pressure changes. Rapid variations in the abnormal gas resistance will lead to the occurrence of channeling. A visualization technology mainly made of pressure distribution was developed to predict BF channeling phenomena in this study. The real-time data of BF shaft pressure was used to create a 3D visual model by neural network algorithms and 3D real-time BF pressure changes were observed. The root mean square deviation (RMSD) of the BF shaft pressure was used as an index to set up the predicting criteria of channeling occurrence with the opening of BF Annular Gap Element (AGE), and a predicting system based on the criteria was built. The two criteria for the channeling alarm are the RMSD of the BF shaft pressure (> 0.15 kg/cm2 ) at the upper two levels, and the AGE opening being greater than 60%. This system has been installed in the China Steel Corporation (CSC) BFs, and the test results showed that a prediction can be obtained 8 to 16 min ahead of channeling allowing sufficient time for the operator to adjust the BF operation in order to avoid the occurrence of channeling.

By Erich J. Jacob, Volker O. Meldner

INTRODUCTION Our company has made persistent efforts to utilize the very latest cost-saving technology in tunnel design and construction. However, we were relatively late in joining the clan of slurry shield tunnelers. The challenge came in 1973, when our company was low bidder on a major sewer tunnel in Hamburg, West Germany. The tunnel was to be driven under the harbor region through coarse and fine sands with up to 60 ft hydrostatic head of water. Outer diameter was 15 ft, and length was 2.9 miles. This contract appeared right to enter the new field of slurry face tunneling. We gathered a design-engineering team to develop the machine, called it "Hydroshield", and used it on the project. The good performance of the prototype machine encouraged us to improve and modify the equipment design. The very latest model is now in use on a subway tunnel in Antwerp, Belgium. This tunnel is 21 ft outer diameter and 2.4 miles in total length. In terms of excavated volume it is the world's largest slurry shield contract. While the drive is still in full swing, we are currently preparing for 3 further Hydroshield applications, with diameters ranging from 12 to 32 ft. This paper describes the Hydroshield's salient design features, operational characteristics, construction reliability and performance levels, as experienced in West Germany and Belgium.

Jan 1, 1979

By Lewis J. Patterson

In the period of time allotted to this paper, an attempt will be made to cover a great deal of territory, figuratively speaking, as far as our experience with ammonium nitrate is concerned. In giving this subject the "broad-brush" treatment, it will be necessary to generalize on the major points which at the same time will permit me to avoid, to a great extent, any involvement in the purely technical and theoretical aspects of blasting. The practice of theorizing before a new idea is tried has practically been discontinued in our organization simply because experience has shown that, almost without exception, theories have fallen aside as some new development takes its place. In regard to blasting, logic and experience seem to have little place in this phase of quarry operations. As the use of low cost blasting agents was introduced in our operating practice, a man who had no previous experience in the field of blasting but with sound knowledge in safety procedures was given the responsibility of supervising the drilling and blasting operations. A total lack of experience is not ordinarily recommended as a prerequisite to assuming the responsibilities of a supervisory position. However, in this case it was obviously a wise decision because there were no pre-conceived ideas as to what techniques would or would not be successful.

Jan 1, 1958

By Andrew P. Gize

The analytical approaches used to solve a specific problem are dependent upon the information required, coupled with limitations imposed by available facilities, costs, and time. The organic matter associated with ore deposits has the potential to yield information for two problems. Information can be obtained to provide guidelines for prospecting, and, secondly, to solve genetic problems. A major potential of organic matter in providing prospecting guides lies in the high thermal sensitivity of organic matter in sediments which are metamorphosed at grades lower than greenschist facies. The organic matter can then be used to map thermal anomalies potentially associated with mineralization. The analytical approach is to determine the thermal maturity of the total organic matter, or of specific fractions, using techniques which are relatively quick and inexpensive. Consideration of genetic models (for example, reduction, complexing, involvement of oil field brines) generally requires more specific information than the overall thermal maturity of the organic matter, necessitating infor¬mation on molecular composition and structure. The facilities, time, and cost of this information are greater than for mapping thermal anomalies. The analytical techniques discussed include elemental analyses, spectroscopy (infra-red, visible and ultra-violet), Fourier Transform infra-red, nuclear magnetic resonance, extraction, pyrolysis techniques, chromatography and mass spectrometry.

Jan 1, 2013

By Karl H. Bruemmer

1. TRENDS OF DEVELOPMENT IN THE MECHANICAL DRIVING OF UNDERGROUND EXCAVATIONS IN THE GERMAN COAL MINING INDUSTRY The demand for higher advance in underground excavations led, in the past ten years, to the development and application of various mechanical methods in the coal mining industry of the Federal Republic of Germany. Hence, a modern mine cannot operate anymore without tunneling machines for the driving of horizontal and inclined roads and shaft boring machines for the sinking of shafts. In future, boring operations will assume a high positional value in the mining industry, as the development of cutters has kept pace with the development of machines. In the past ten years, about 40 km of roadways have been bored by tunneling machines in the German coal mining industry, further 140 km will be bored by 1990, part of which are already under contract. The idea was tempting to apply the technology of horizontal tunnel borers also to the sinking of vertical shafts. The underground contractors Deilmann-Haniel GmbH of Dortmund and Thyssen Schachtbau GmbH of Mülheim/Ruhr developed already in 1970, together with Wirth of Erkelenz, a shaft boring machine working without drill pipes, capable of sinking shafts following a pilot borehole, according to the downward reaming method (Fig. 1). In the meantime, two such shaft borers are operating in coal mines with diameters of 4.50 m to 6.50 m. Recently an order was placed for a third Wirth shaft borer for diameters up to 8.50 m. Since 1971 about 3.800 m of open or blind shafts have been sunk by the reaming process (Fig. 2).

Jan 1, 1979

By R. L. Loofbourow, Robert R. Miller

Deep, stable, unlined space promises secure, efficient, acceptable solutions to several current problems. With truly favorable conditions, it can be economic as well. The basic requirement is sufficient sound, tight rock at required depth. This and unusual surface requirements point to special testing. An objective is to describe conditions for planners, estimators and contracts. A first stage concept study needn't be prolonged but should overlook nothing significant. Although observations and tests on core are considered essential, time and expense can be cut by supplementing then with tests on walls of rotary or percussion holes. In some places initial drilling could be shallow.

Jan 1, 1981

By T. Harrison

Surface coal mines in West Virginia are receiving stringent NPDES discharge limits for total recoverable selenium. With limits in the low parts-per-billion range, selection and implementation of proper sample collection and analytical methods are imperative for quality assurance and control and for consistency in results. Given the typical oxidized form of selenium in the water, the low limits and the large and variable flow rates from the watersheds, end-of-pipe treatment is difficult and cost-prohibitive to implement. Discharge locations in the remote and steep terrain exacerbate the problem. To evaluate options for end-of-pipe treatment at a Patriot Coal Corporation surface mining operation in West Virginia, CH2M HILL performed wastewater characterization for a range of key constituents and selenium species at three outfalls for selection and preliminary sizing of appropriate treatment processes. A preliminary evaluation of base and wet-weather flows was done to understand flow variability considerations for discharges. A conceptual evaluation of technologies to treat selenium to permitted levels was conducted in con-junction with order-of-magnitude life-cycle cost estimates.

Jan 1, 2010

By Noriyuki Fujii

It is no need to say that exploitation of industrial minerals has a close relation to development of the industries related. In the first stage, a small scale manufactures were initiated in areas producing some main raw material minerals. China and cement manufactures, for example, were established depending on the local occurrence of raw materials such as kaolin and limestone without exception. That is, the industrial development is greatly influenced by the local production of the raw materials in the stage. With the development of industrial technology, various kinds of raw material minerals are explored to meet the demands of industries in the second stage. New materials become indispensable, and low-grade raw material minerals, which were left as useless, are developed as useful materials. In the stage, the development of raw material minerals is accelerated by that of industrial technology related. However, industries mainly rely on domestic production of the min raw material minerals.

Jan 1, 1981

By Edward O. Reinbold

The paper presents the results of a study which involved collection and analysis of airborne pollutant concentration data in two producing underground room and pillar metal mines which use diesel powered equipment in the area near the face. The results include the concentrations of CO2, CO, NO, NO2 and respirable particulate matter measured with the latest portable instruments, and the carbon and hydrogen contents of the particulate matter samples determined by combusting them in a Elemental Analyzer. The carbon and hydrogen contents are used to estimate the amount of diesel particulate matter in the mine ambient air. The short term grab sample concentration data, although not suitable for determining compliance with ACGIH Threshold Limit Values (TLVs), are related to the TLVs so that they may be compared conveniently. Lognormal frequency distributions and the arithmetic mean of the concentration measurement data are used to compare different mine situations. Conclusions are drawn as to which pollutants are most important to control under actual mine production conditions.

Jan 1, 1979

By Gary A. Perry

Cyprus Sierrita produces copper and molybdenum from its Sierrita and Twin Buttes open pit mines south of Tucson, AZ. Both pits were started in the late 1960s and are more than 460 m (1500 ft) deep. Sierrita has used a Caterpillar 992C Remote Controlled Loader since January 1993. The loader was justified to increase safety and profits at Sierrita. It has exceeded all expectations. As of June 1993, the 992C had produced additional profits of more than $1.5 million. Safety and Geotechnical The safety of Cyprus personnel and equipment is always of prime concern. The remote controlled loader removes personnel from the active raveling area. But it requires prudent operation. The remote controlled loader discussed here is always intended to be used in a safe manner under a managed slope. Any increase in slope angle or use of any equipment under a critical slope is taken only after careful analysis of the specific

Jan 1, 1994