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By H. Köse, C. Tatar, C. Helvaci, F. Simsir

The Çayirhan coal basin is located 124 km (77 miles) west of Ankara,Turkey. With approximately 520 Mt (570 million st) of lignite reserves, the Neogene Çayirhan basin is one of the important coal districts of the central Anatolia region. The Çoraklar formation consists of crossbedded sandstone, channel fill conglomerates, mudstones, carbonaceous shales and volcanoclastic pebblestones, which are fluvial in origin. The lower and upper lignite seams occur, respectively, in the lower and the uppermost parts of the Çoraklar formation. The lignite deposits are in the Çayirhan and Koyunagili portions of the Beypazari Neogene basin. The Çayirhan coalfield consists of lower and upper lignite seams. The lower lignite seam does not outcrop at the surface. Its lateral discontinuity and relatively low sulfur content, plus sedimentologic and stratigraphic features of the associated sediments, indicate a fluvial origin. Thus, the lateral spreading and geometry of the lower lignite deposits were controlled by the channel, flood plain and well drained marshes of a fluvial system. The mining method employed at Çayirhan is the fullymechanized, retreat, working longwall with caving system. Due to ventilation, haulage and tectonic conditions, panel lengths from 0.6 to 1.7km (0.4 to 1.1 miles) are chosen, and 220-m (720ft) face lengths are used. The annual coal production is 2.2 Mt (2.4 million st).

Jan 1, 1994

Energy Developments Ltd. (EDL) has developed power plants at two Australian coal mines that featuring 94 gas-fueled Caterpillar G3516 engine/generator sets. They will convert to electricity 145 kt/a (160,000 stpy) of coal-seam methane gas for sale to a local utility. The $100-million project will cut the sites' methane emissions in half, provide a low-cost energy source and offset mine operating costs. The project began in May 1995. It is located at the Appin and Tower longwall underground mines, 80 km (50 miles) south of Sydney in New South Wales. The installation is one of the first to capture coal-seam gas from mine ventilation air and gas drainage systems. Coal- seam gas contains 40% to 60% methane, which fluctuates constantly. The system is expected to convert 578,000 m3/d (20.4 million cu ft/d) of coal-seam gas to 94 MW. It will also reduce greenhouse gas emissions by 3.5 Mt/a (3.8 million stpy) of CO, equivalent emissions. The Appin and Tower mines each produce 2 Mtla (2.2 million stpy) of clean coking coal. They operate around the clock with about 400 workers per site. The mines are owned by BHP Steel, Collieries Division, which will share the revenues from energy sales. The Appin Power Partnership consists of EDL and Lend Lease Development Corp.

Jan 1, 1997

By Elif Çevik

This study deals with the mineralogical-geochemical characteristics and the industrial usage of the olivine from the dunites that crop out on the west of the Topuk village (Orhaneli). Mineralogical compositions of non-altered dunite samples are averagely as: Olivine (>90%), serpentine (1-4 %), opaque minerals especially chromite, magnetite, pyrite (1-3 %), and secondary minerals as magnesite, chlorite (1-2 %). X-Ray Diffractograms of the dunite samples indicate that olivines are in forsterite (93 on an average) composition, and chlinochrysotile and lizardite accompany to the forsterite. Chemical analyses of the dunites show that MgO, SiO2, Fe-,03 and LOI contents vary from 40,99 to 50,2 %, 34,67 to 40,6 %, 6,8 tol3,7 %, 0,11 to 11,27 %, respectively. SE-TAT Mining Company states that the study area has 400.000.000 tonnes proved, 800.000.000 tonnes probable and totally 1.200.000.000 tonnes olivine reserve. Consequently, all studies indicate that Orhaneli Olivin has convenient mineralogical and chemical properties and the grain size (0.04-40 mm) for industrial usages such as abrasive, olivine sand products, steel slag conditioner, balast and covering material in industry: Orhaneli olivines are demanded especially from the firms related to refractory industry, iron-steel factories, naval forces and shipyards. SE-TAT Mining Company also exports these olivines to different countries such as Macedonian and Spain.

Jan 1, 2005

By Paul D. Dupree

Introduction Trapper mine is a dip-line strip coal mine, located about 10 km (6 miles) southwest of Craig, CO. The mine provides the Craig Generating Station, operated by Colorado-Ute, with about 2 Mt (2.3 million st) of coal annually. The Trapper mine is situated on a hillside that climbs in elevation from 2 to 2.5 km (6500 to 7400 ft) at average grade of 15%. The coal seams dip at about 16% down-grade and they outcrop near the top of the hillside. They exceed maximum stripping depth in 1 to 1.7 km (3500 to 5500 ft) of pit length. Stripping in the three existing pits is performed with three Page 752 23 m3 (30 cu yd) walking draglines. Two of the pits are currently being cast blasted. Until the active cut, the Derringer pit was cast blasted only where the lower mined seam exceeded stripping capabilities and the pit was a single seam operation. Now, a 9-m (30-ft) interburden bench has been incorporated into the stripping plan. This bench protects the first seam of coal from shear when the overburden is cast blasted. The cast blasted section of the 1.6 km (53,000 ft) long pit has been increased from the 457 m (1500 ft) casted previ¬ously to 1 km (3500 ft). High speed films show the coal losses due to shear of the blast are minimal. The pit width in Derringer pit is 61 m (200 ft). This is necessary for efficient spoil side stripping of a relatively thin interburden in the two-seam section of the pit. The Enfield pit is entirely cast blasted. The single seam pit is 46 m (150 ft) wide, 1.1 km (3600 ft) long, and varies from 15 and 46 m (50 and 150 ft) in overburden depth. The overburden strata at the mine consists of medium-hard layers of sandstone, shale, and

Jan 1, 1987

By William R. Nash

The scope of work for the fast track construction of the Weeks Island Replacement Facility, Weeks Island, Louisiana included the design and construction of two salt mines. Mine #1 - An interim underground mining level consisting of a 975 m (3200 ft) incline and 3520 m of 5.5 m x 7.3 m (11560 ft of 18 ft x 24 ft) drill and blast excavation; raise boring; core drilling; roadheader excavation; complete bulk material handling facilities utilizing an existing production shaft. Mine #2 - Simultaneous with the interim mine construction a new one million ton per year underground salt mine was constructed consisting of: two 5.5 m diameter x 381 m (18 ft diameter x 1250 ft) deep shafts; 76450 cu m (100,000 cu yd) of drill and blast bottom excavation; surface and undergound bulk material handling systems (conveyors, skip loaders, shaft equipment, hoisting); ground freezing for water control for both the production and service shafts; the design of the first underground doublewall slipform installation of a dynamic bitumen shaft lining system; the emergency grouting of both the existing production shaft and the interim mining level in the salt dome; 227 mt x 64 m (250 ton x 210 ft) high structural steel production headframe; 2.2 MW (3000 hp) double drum mine hoist; service shaft headframe; and service buildings.

Jan 1, 1987

By J. A. Dos Santos

High angle conveyor (HAC®) systems in open pit mining offer many advantages over the traditional, truck only, haulage systems, including: (1) superior energy efficiency, (2) less dependency on petroleum products, (3) less sensitivity to inflation, (4) less labor, (5) less excavation for the amount of ore recovered, and (6) less ramp construction and maintenance costs. Previous studies had revealed the technical and economic feasibility of high angle conveyors. This paper presents the Sandwich Belt HAC® as the vital link to optimization of in-pit conveying systems. HAC development to date is discussed, beginning with studies in 1979, to the first large scale prototype in 1983, to the first commercial unit in 1984, into "the latest commercial installations. Discussion continues with the HAC systems to suit the various open pit mining operations and the corresponding characteristics of the system components, particularly the high angle conveyor. The range of HAC systems from the low capacity (up to 1,814 t/h), low lift (10.7 to 36.6M), highly mobile to the moderate capacity (1,814 to 3,629 t/h), moderate lift (36.6 to 76.2M), intermittently mobile to the high capacity (greater than 3,629 t/h), high lift (greater than 76.2M), semi-mobile, are discussed along with some possible combinations of these.

Jan 1, 1989

By Keiichi Fujita, Katsumoto Ueda, Hiroshi Nakauchi, Naohiko Okumura

INTRODUCTION This paper presents (1) modified slipform system which was employed for simultaneous concrete placement for permanent lining and Instruction of a partition wall in the execution of a ventilation shaft 620m deep, and (2) current shaft sinking techniques which have been applicable and efficient for the subsurface conditions in Japan. MODIFIED SLIPFORM SYSTEM FOR PERMANENT LINING OF VERTICAL SHAFT General Information This paragraph deals with rapid construction by using modified slipform system for the permanent concrete lining and a partition wall of ventilation shaft, which has inside diameter of 620m and depth of 620m, of Enasan Highway Tunnel. The general feature of the shaft is illustrated in Fig. 1 and standard section of the shaft is illustrated in Fig. 2. The geological condition surrounding the shaft is mainly of ryolite and surface is of talus, but as a whole, they are rather weak and weathered rocks with faults, fissures and clay seams. 220mm borehole for the geological investigation was used as a drainage hole, predicting the amount of water inflow into the shaft to be 10t/min. The shaft was executed mainly by means of the conventional short step sinking method of 1.2m lift, employing temporary headframe and hoists. For each lift, 40 to 50cm thick temporary concrete lining was used. About 28,600m3 of rocks were excavated and

Jan 1, 1979

By D. L. Misterek, E. J. Slebir, G. W. Ring, M. A. Laird

INTRODUCTION In 1973, the Federal Highway Administration (FHWA) initiated a 10-year program of research on tunneling technology for future highways as a part of a larger Department of Transportation effort on tunnels. The objectives of the FHWA program are to: improve tunnel design technology, reduce costs, minimize adverse environmental impact due to construction, increase the rate of construction, and assure the maintenance of a safe and attractive tunnel environment. The program is divided into four research tasks designed to solve tunneling problems identified by the engineering and field offices of the FHWA. These tasks are as follows: 1. Cut-and-Cover Tunneling 2. Site Investigations 3. Ground Movements - Prediction and Control 4. Highway Environmental Criteria for Tunnels In order to provide input into Tasks 2 and 3, the FHWA is sponsoring an investigation and testing program by the U.S. Bureau of Reclamation to instrument and monitor two sites in the second bore of the Eisenhower Memorial Tunnel located on Interstate Highway 70 at Loveland Pass approximately 97 km (60 miles) west of Denver, Colorado. The tunnel will be approximately 14.0 m (46 ft) in diameter when excavated. The study is designed to generate data on: (1) changes in the state of stress, and movements during and after tunneling, (2) tunnel lining design requirements, (3) developing a

Jan 1, 1976

By B. G. Long

Coastal States Energy Company (Coastal), a wholly-owned subsidiary of The Coastal Corporation of Houston, Texas, owns coal mining operations in Utah and Kentucky. One of the Utah operations, Southern Utah Fuel Company (SUFCo), located 30 miles west of Salina, Utah, has been operated by Coastal since 1974. This operation is a single-seam, six-section mine operated from one portal area. It produces 2.2 million tons of coal per year and has a payroll of approximately 300 employees, Coal is mined by continuous miners, hauled by diesel-powered haulers and transported by belt conveyor to outside crushing and screening facilities. Sized coal is hauled by contract truckers 80 miles to a unit-train facility located at Levan, Utah.

Jan 1, 1983

By Dennis Molvik, Omar Fulton, Chris D. Breeds, Don Gonzales

The Tolt Pipeline No. 2, West Snoqualmie Valley project, is part of a water supply project linking the Tolt reservoir in East King County to the City of Seattle through a nominal 2.13 m (7-ft) inside diameter conveyance. Receipt of the National, 2002Microtunnel Award provided recognition of the many challenges overcome by this project. Baseline conditions revealed in the Geotechnical Documentation included over-consolidated glacial deposits, landslide and alluvial deposits, artesian water, boulders up to 36-in in diameter, logs, heaving sands, and liquefiable soils beneath the river. Schedule constraints associated with setting the shafts in the floodplain of a salmon bearing river and the fickle performance of the river during those times it was not supposed to flood added to the challenge.

Jan 1, 2003

By J. J. Moore

Combustion synthesis, or self-propagating high-temperature synthesis (SHS), reaction systems are discussed with respect to thermodynamics and kinetics. In particular, the effect of the process parameters, e.g. particle size, [All] ignition and combustion temperatures, on these self-sustaining reactions is discussed. Combustion theory is used to investigate the effect of the overall actuation energy of the SHS reaction on the combustion front propagation rate and in obtaining a clearer understanding of the transition from stable to unstable propagation. Finally, examples of the application of combustion synthesis to advanced materials processes are made, in particular the synthesis of Ni-Ti-X intermetallic shape memory alloys, TiC-AI2O3 and ZrB2-AI203 ceramic composite materials.

Jan 1, 1992

By T. van Sandwijk, G. Van Weert, E. Molleman

This paper reports on test work that explored the dissolution/precipitation reaction: ZnS + 2HCl - ZnC12 + H2S, which is part of a process used in the production of pure ZnS. The research focused on the influence of proton activity on the dissolution of zinc concentrates obtained from the Brunswick Mine No. 12 in Canada (Brunswick Mining & Smelting); the Red Dog deposit in Alaska (Cominco Ltd.); and the Tara deposit in Ireland (Outukumpu Zinc). A comparison between the results of the experimental dissolution as a function of pH and the dissolution predicted by thermodynamics suggest that the three concentrates contained sig¬nificant amounts of the more reactive mineral wurtzite, although XRD analysis showed mainly the presence of the mineral sphalerite.

Jan 1, 1999

By Bruce A. McKinstry

For many major mining projects the time frame from initial planning to production can be measured in terms of decades. Hecla's Silver Shaft project, which is scheduled to go into production by the end of this year and includes a complete surface facility, shaft with an ultimate depth of 2,348 meters (7,700 feet), complete ore pass and loading pocket system, and 610 meters (2,000 feet) of development drifting and stope preparation, was initially concieved in the Fall of 1979. This duration of a mere four years from conceptual engineering to production is a testimonial to what can be accomplished when a progressive mining company and an innovative contractor work together as a team rather than developing into two warring camps as often happens.

Jan 1, 1983

By G. Schriever, H. Thiel, E. J. Foell

A long-term, large-scale, disturbance-recolonization experiment with relevance to the environmental effects of deep seabed mining is described. The study is funded by the German government and was launched in the abyssal eastern tropical South Pacific Ocean in February-March, 1989. After obtaining pre-impact baseline environmental data, a 10.8 km2 (4.2 sq miles) circular area of seafloor was disturbed using a specially designed "plow-harrow" device. An initial post-impact sampling series was carried out immediately after disturbance followed by a second post-impact sampling series six months after the disturbance. Plans call for repeated visits to the site at two year intervals to monitor the anticipated slow recolonization process until the area is inhabited by a new, stabilized community.

Jan 1, 1993

By G. G. O. O. Uwadiale, M. A. Kollere, M. A. U. Nwoke

Birnin Gwari and Alawa graphite deposits were upgraded by flotation. Using 0.5 kg/t kerosene and 0.25 kg/t sodium silicate, flotation concentrates grading 90.7% and 88% Cg with recoveries of 86.2% and 84% were produced from Birnin Gwari and Alawa graphite samples, respectively. The combination of 0.5 kg/t kerosene, 0.2 kg/t pine oil and 0.25 kg/t sodium silicate yielded high-grade graphite (92.3% Cg) with a recovery of 83.9%. Flotation with refined rubber nut oil and kerosene, at a 1:1 ratio, produced a concentrate grade of 86.3% Cg with a recovery of 90.4%. With acid leaching of the flotation concentrate, a high-grade graphite concentrate containing 98% Cg was produced.

Jan 1, 1998

By McDonald E. Wrenn, Narayani P. Singh, Victor E. Archer, Ceno Saccomanno

Fourteen uranium miners' lungs from Colorado plateau were collected at autopsy and the concentrations of 238U, 234U and 230Th were determined by radiochemical procedures utilizing solvent extraction - alpha spectrometric techniques. The uranium and thorium isotopes are in near equilibrium with average concentrations of 238U, 234U and 230Th being 89.3, 95.2 and 91.1 pCi/kg respectively. The combined average radiation dose rate to lung from these three isotopes is about 24.2 mrad/year at death excluding the unmeasured contribution from the 226Ra and daughters. The average concentration of 230Th is about 65 times higher than the mean concentration of 230Th in lungs of non-miners dying at comparable ages from the same region.

Jan 1, 1981

By Gunder Homstvedt

The paper presents a new method for boring of blind inclined shafts. The machine, called BorPak, developed by The Robbins Company, operates similar to a mini TBM. It is a remote operated, self propelled drilling machine mounted on a crawler for high mobility and launched out of a starting tube for quick collaring. A short history of the operation of the prototype in Scandinavia and Canada is included in the paper. The BorPak is capable of boring raises at angles from 30° to 900 from horizontal in sizes ranging from 1.2m-2m diameter without the use of drill pipe. The BorPak represents an innovative tool for improved performance, reduced costs and creating a safer working environment.

Jan 1, 1993

By Ron VanRiper, Ben W. Burdett, Randy A. Ynchausti, Jeff D. McKay, Dan Lampshire, Thomas W. Toronto

An adaptive process control system was installed in Cortez Gold Mines Mill #2 Grinding Plant in Nevada. The installation, commissioning, and testing of the system took approximately 80 manweeks, but final test results show that the system paid for itself through increased throughput within two weeks of commissioning. Both crisp and fuzzy rules are used in the expert rule base which is also integrated with continually adapting neural network models. The expert rules and models are used by predictors, and optimizers to allow the control system to provide optimum process performance under continually varying feed conditions. The selection, installation, rule and predictor configuration, and statistically verifiable testing of the control system in the Cortez Gold Mines Mill #2 Grinding Plant is described in the paper.

Jan 1, 1999

By Wade E. Cooper

INTRODUCTION How accurate are past and present employee radondaughter exposure records of underground uranium miners employed in the United States? This often-debated question is essential for future substantiation of safe exposure limits. An apparent discrepancy between company-reported exposures and Mining Enforcement and Safety Administration (MESA) projected exposures was detected in 1977. For these reasons a need for an updated comparison of these exposure data was indicated. This paper gives some of the conclusions of the earlier study and compares more recent exposure records compiled by the Atomic Industrial Forum, Inc., with projected exposures based on sampling by Federal mine inspectors. EARLIER STUDY In its 1977 Annual Report (U.S. Department of the Interior, 1978), MSHA's predecessor, the Mining Enforcement and Safety Administration (MESA), reported that there was "an apparent discrepancy between Federal inspection results and company records." Both company records and MESA's projections from samples taken during routine Federal inspections indicated reductions in the average exposure of underground uranium miners from 1975 to 1977, but the MESA projections were over 4 times higher than the company-reported averages. This apparent discrepancy however, was based on a comparison of exposure data reported for all U.S. underground uranium miners. This projection more closely represented the average exposure of U.S. underground uranium mine production workers who worked 1,500 hours or more during the year. Exposures of such workers are reported each year by the Atomic Industrial Forum, Inc. (AIF) in summaries of exposure data reported to the AIF by uranium mining companies throughout the United States. (The AIF exposure summary for 1979 appears as tables A-1 and A-2 in the appendix of this paper.) Assuming that the average exposure for each exposure range category is the midpoint of each exposure range category, table 1 compares the estimated average exposures for U.S. underground uranium mine production workers who worked underground 1,500 hours or more each year in 1975 through 1977 with the exposures projected by MESA for those years. [Table 1. - Average Exposure and Projected Average Exposure for U.S. Underground Mine Production Workers Who Worked Underground 1,500 Hours or More During the Year. Company, MESA?' Reported- Projected Year (WLM) (WLM) 1975 1.59 5.68 1976 1.84 4.64 1977 1.68 4.08 1 Atomic Industrial Forum, 1976, 1977, 1978. 2 U.S. Dept. of the Interior, 1978.] Table 1 indicates that, even after adjustment to ensure better comparability an apparent discrepancy between Federal inspection results and company reported exposures for 1975-1977 exists; however, the apparent discrepancy diminished over the 3 years. Slade, 1977, explained some of the discrepancy between company records and MESA projections of miners' average radon-daughter exposures as follows: 1) Concentrations of radon daughters in some work areas can vary greatly during any one day. A variation from 0.3 WL to 17.0 WL has been measured in the same stope on the same day. 2) Seemingly simple abatement problems indicated by the regular Federal and State inspections were solved simply by manipulating the mine ventilation. 3) The methods used by mine operators to compute cumulative exposures were such that high radiation readings were seldom or never reflected in the records. For example, a work area sampled on Monday indicated a radon-daughter level equal to 0.2 WL and this was recorded. It was sampled again on Wednesday of the following week and the level was 2.2 WL. The miners were withdrawn or told to fix the ventilation, and when this was accomplished the area was sampled and found to be at 0.2 WL again. Although the miners could have been working in the higher concentration up to 6 days, this reading might never be reflected in their records. If it was recorded, only a fraction of the day on which it was discovered would be entered into the cumulative exposure calculation (time-weighted average). 4) Some of the mines visited used a mine average radiation concentration, and every employee working underground was given the same exposure per unit of time spent underground. As a result of the 1977 study, more stringent sampling and recordkeeping standards were proposed and public hearings held in 1977. The resulting new and revised health standards on radon-daughter sampling and exposure recordkeeping became effective August 30, 1979 (Mine Safety and Health Administration, 1979). Prior to these new regulations, radondaughter sampling requirements were on an "as often as necessary" basis (Code of Federal Regulations, 1978). The new regulations required practically all active work areas in underground mines to be sampled at least once every 2 weeks, with many areas requiring weekly sampling. They also required calendar-year exposure records of all underground

Jan 1, 1981

By C. M. Liu

"The Freeport-McMoRan Sierrita Crystal Plant produces Copper (II) Sulfate Pentahydrate (CuSO4·5H2O) through a series of cooling crystallizers. In this process, high supersaturation and unwanted spontaneous nucleation promote fine crystals. Seeding through recycled crystal classification can manipulate the crystal size distribution (CSD) for larger crystals. Proper selection of the crystallizer for seeding can prevent spontaneous nucleation and promote final crystal size. This study shows when seeding temperature is closer to the crystallizer temperature, suspension densities in the crystallizers are promoted and overall CSD shifts to a larger size of crystals. INTRODUCTION Figure 1 shows an overview of the crystallization process. The in-plant feed flow, called Pregnant Mother Liquor (PML), enters the first crystallizer and is subsequently cooled through a series of four crystallizers. Specific temperatures are targeted for each crystallizer to ensure the crystallization process is operating within the metastable zone (MSZ). The discharged flow from crystallizer #5 then enters two cyclones. The overflow from the cyclones contains smaller crystals providing seed crystals for crystallizer #5. The underflow from the cyclones begins the drying process. The overflow from crystallizer #5 enters cyclone #3 for removal of fine crystals and seeding purposes. The underflow from cyclone #3 has the capability to provide seed crystals for crystallizer #1 or crystallizer #2. The overflow leaves the system as Spent Mother Liquor (SML). Undersize crystals dissolve into the PML and return back to crystallizer #1.THEORIES AND METALLURGICAL TESTS Seeding requires an understanding of the crystal size, solution temperature and amount of crystals that enter the crystallizers (1). For the seed crystal size, classified crystal seeds can prevent fine crystals returning back into the system which eventually leads to excessive agglomeration (2). Proper selection of the crystallizer can ensure seeding at an appropriate temperature. Seeding at a temperature much lower or higher than the saturation temperature promotes spontaneous nucleation. Typically, seeding between 4-5°F below the saturation temperature is acceptable (5). A general rule of thumb is to add the seed crystals at the temperature between the solubility curve and the metastable zone. An experiment conducted by Mettler-Toledo AutoChem, Inc. indicates seeding close to the solubility curve rather than the metastable zone promotes a lower supersaturation and nucleation rate but yields a higher growth rate and a greater number of larger crystals (1). The amount of seed crystals can not only change the suspension density but also narrows the width of the MSZ in the crystallizers. An experiment conducted by Jaroslav Nyvlt reports with the crystals absent, the maximum allowable undercooling is 6.3 degrees at a cooling rate, 5°C/hour. With the presence of crystals, it narrows the MSZ width to 2.2 degrees (4). Industrial crystallizers normally operate at suspension densities between 15% and 25% by mass. When suspension densities are lower than 15%, it increases the risk of primary nucleation and the probability of incrustations; on the other hand, if the suspension densities are greater than 25%, it can cause a greater attrition rate and increase the probability of deposits (6). Moreover, operating suspension densities between 15% and 25% are also sufficient to minimize supersaturation rate which promotes crystal growth over nucleation (2, 6)."

Jan 1, 2015