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To meet the energy requirements, hydroelectric projects are planned and executed in many countries. Though these projects requires a high capital investment, the returns are regular with minimum maintenance after commissioning of the project and are ecofriendly. Bhutan is situated in the eastern Himalayas and covers an area of 38,394km2 (14824.01sq. miles. It is bordered by India in East, South and West and by Tibet in the North. The hydropower potential of the country is estimated at 30,000MW, out of which around 5% has been harnessed.

Jan 1, 2016

By Frank E. Chase

Clay veins, also referred to as clay elastic dikes, have been responsible for numerous underground injuries and fatalities. These hazardous structures are also responsible for increased production costs during all phases of mining. For these reasons, the Bureau of Nines has investigated the physical characteristics of and roof instability problems associated with clay veins in order to make support and other mining recommendations. In addition the occurrence and origins of clay veins were examined to determine whether or not the structures could be projected into unmined portions of the coalbed. This investigation included portions of the Arkoma, Illinois, Northern Appalachian, Southern Appalachian, and Uarrior Coal Basins. Virtually a11 clay veins observed or documented occurred in the Illinois and Northern Appalachian Basins. Observed clay veins ranged in sire from 1 inch to 16 feet In cross-section and were found under shale, siltstone, sandstone, and limestone roof rock. Individual clay veins were predominantly composed of claystone; however, limestone. siltstone. and sandstone infilled clay veins do occur. Clay vein formation has been associated with the infilling of fissures which result from compressive, tensile, or shear ground failures. These gaping fissures were propagated by compactional processes and/or tectonic stresses active during and subsequent to coal iff cation. Associated fault, fracture, and slickenside planes commonly parallel clay veins and disrupt the lateral continuity of the immediate and, sometimes, main roof. When clay veins parallel or subparallel the direction of face advance the roof is segmented into cantilever beams causing unstable conditions. Therefore, the strata on either side of the clay vein must be bolted and strapped together to form a beam.

Jan 1, 1984

The risk associated with mining induced seismicity is one of the major threats to the safety and sustainability of deep underground mines. This paper describes techniques that allow site practitioners to efficiently control such risks in mines. The proposed approaches rely on ground support to strategically control seismic risk and re-entry time to tactically control this risk. The strategic approach is based on the detailed understanding of past seismicity to as certain the seismic hazard of individual sources throughout the mine. This approach also relies on assessing the potential damage that these sources can induce on nearby excavations using the excavation vulnerability potential (EVP) and rockburst damage potential (RDP) concepts proposed by Heal et al. (2006). It is then possible to investigate how to reduce the risk of experiencing damaging seismicity in mine drives by locally enhancing the ground support system. The tactical approach relies on a proposed methodology to estimate reliable re-entry times or exclusion periods based on the seismic decay following blasting. Some examples of how these techniques have been applied in Australian mines are given.

Jan 1, 2009

By John J. Sammarco

The U.S. Bureau of Mines seeks to increase safety and efficiency in U.S. coal mines. One approach is to develop technology for automation of a continuous mining machine. Realization of an autonomous mining machine requires development of subsystems for machine intelligence, navigation-positioning, and computer control. This report focuses on investigation of one subsystem, an onboard heading system, which would be responsible for determining and controlling machine heading. The onboard heading system investigated is a multisensor system to determine machine heading, pitch, and roll. A directional gyroscope provides heading (yaw), fluxgate sensors provide a compass heading, and gravity-referenced clinometers give machine pitch and roll. The system utilizes a dedicated microcontroller networked to an external system of computers. Tram commands, supplied to the network from external computers, are executed by the onboard system. Sensor feedback is employed for closed-loop control of machine heading by controlling pivots and turns. The report discusses operating limitations and error sources of system sensors and presents test results of closed-loop control of machine heading. Results of tests with a mining machine are used to exhibit various sensor shortcomings and to evaluate control of pivots and turns.

Jan 1, 1990

By K. W. Grubaugh

Indigenous people are nearly always affected when projects enter their territory. Crop and other asset compensation can help or undermine a project’s progress depending on the approach. When compensation is handled poorly, a technically viable project can get indefinitely entangled by local unrest. Stake holders associated with compensation issues include; the state, the indigenous people, non-governmental organizations, and the developer. Appreciation for the unique perspective of indigenous peoples and the influences affecting them can avert problems and prevent delays. A review of the compensation issues encountered in Ghana during its recent gold boom can assist in avoiding problems associated with handling poor and uneducated people.

Jan 1, 2002

By Clifford Britch

"Kaiser Resources Ltd. has completed feasibility studies resulting in approval of $277,500,000 for the construction of the Greenhills Surface Coal Mine, located 35 km north of Sparwood, B.C. The mine is designed to produce 1,800,000 tonnes per year of metallurgical coal over a 20-year period by conventional truck /shovel methods.The project is in the detailed design phase, with some preparation work being carried out on the site. The major construction activities are scheduled to commence in the spring of 1981. Mine development and pre-stripping will commence in July 1981, with first coal production scheduled for mid 1983.This paper will be a general description of the project and will include a discussion of the geology, reserves, mine planning, coal handling and processing, surface facilities and related topics.IntroductionProject DefinitionThe Greenhills Project is designed to produce, by conventional truck I shovel surface mining methods, 1,800,000 clean tonnes of metallurgical coal per year for twenty years . The production/ life constraints were chosen as being meaningful for planning and evaluation purposes after appraisal of the market potential and are not limited .by economic reserves. Substantial additional strippable reserves are available which would facilitate expansion of the proposed mine life and/ or capacity. In fact , all the facilities are designed so that they can be expanded in the future to accommodate a doubling of annual coal production, and certain portions of the coal processing facilities are being installed with an annual capacity of 3,600,000 tonnes. The mine will also produce approximately 2,400,000 clean tonnes of oxidized thermal coal, mostly in the first decade."

Jan 1, 1981

Reports by researchers in government, industry, and universities of the United States are given for various projects on basic coal research concerning, the metamorphism, physical and chemical properties, and reactions of coal, and how many of these studies can lead to better utilization of coal.

Jan 1, 1968

By C N. Whata

While there is no specific obligation on the part of any applicant to consult directly with tangata whenua (people of the land), recent cases highlight the need to engage in active consultation in order to avoid serious objections and delay, particularly where a proposal may affect the matters referred to in section 6(e) (Waahi tapu/sacred places) and 7(a) (KaitiakitangaiGuardianship) of the RMA.   The Environment Court has shown some sympathy for tangata whenua where waahi tapu and other significant matters of cultural concern are at risk because of a proposed development. There are several practical steps that can be taken to minimise the potential for serious objection including: ò knowing who to contact and how to contact them; ò demonstrating empathy for the concerns of tangata whenua; ò engaging in proactive consultation, for example meeting at a time and a place that is suitable to tangata whenua, and a preparedness to meet the costs of tangata whenua etc; ò demonstrate an awareness of tangata whenua issues; being aware of the types of mechanisms that are available to remedy, avoid etc adverse effects on matters of concern to tangata whenua.

Jan 1, 1997

By E. D. Gardner

This paper discusses prospecting for lode gold and lists the principal lags and. regulations pertaining to locating; lode claims on public lands. It is a preprint of a part of a bulletin being prepared by the United States Bureau o Mines entitled "Equipping, Developing and Operating Small Gold Mines". The increased interest in gold mining manifested during the past few years (1932-1935) bas stimulated prospecting. Many adventurers have taken to the field to search for now gold deposits. A. large percentage of them have had no previous experience in prospecting for lode gold; this paper has been written with the tope that it might assist these newcomers.

Jan 1, 1935

By William R. Yernberg

In October 1999, Liebherr-America, Liebherr Construction and Liebherr Mining Equipment held anopen house at its Newport News, VA, plant. The open house was held to celebrate the company’s50th anniversary and to demonstrate the new TI 272mining truck. Attending the open house members of the media, vendors and company representatives from all over the world. In his introductory comments, company president Peter Eller announced Liebherr’s dedication to expanding its presence in North America. Liebherr now has 30 dealers across the United States. As part of the open house, a brief history of Liebherr was presented, beginning with its creation in1949. Liebherr engineering and sales representatives were available to answer questions.

Jan 1, 2000

By Zhiyun Li

Room temperature infrared reflection spectra of 2 n-type homo-epitaxial epifilms have been measured in the work. The effect of the refractive index on the determination of layer thickness using traditional calculation measurement is studied and some improvements have been added to the measurement to improve the accuracy and stability of the measured results. Results of the improved method have great agreement with the results from SEM and both variance and mean relative error decrease an order of magnitude.

Jan 1, 2010

By I. L. Follington

This paper describes the research and development programme to develop a prototype underground auger mining system aimed at developing and demonstrating an underground auger mining system able to provide economic access to thinner (<1.8 m) coal reserves of South Africa. Data concerning the performance of modern coal augers under South African coal mining conditions were gained from a proven surface auger which operated across a range of coal types. These data were analysed and considered in conjunction with historical information regarding previous attempts at building underground augers dating back to the 1950s. Drawing on these data a prototype underground auger mining system, the BryDet BUA 600 underground coal recovery auger, was designed and manufactured by the BryDet Development Corporation in collaboration with Eskom and Cutting Edge Technology Pty Ltd with support from Anglo Coal and the Ingwe Coal Corporation Ltd. The prototype BryDet BUA 600 underground coal recovery auger commenced trials in March 2000 at the Matla Mine near Witbank in South Africa. The initial trials were undertaken in an open cut to facilitate the commissioning and training associated with a prototype mining machine. A total of 30 holes was augered in the box cut before the machine moved underground. The prototype BUA 600 first achieved the target penetration depth of 80 m in its third hole. The prototype BUA 600 is a new underground mining system which has passed early testing with ?flying colours? and could provide access to extensive underground coal reserves unmineable by conventional mining techniques both in South Africa and elsewhere around the world.

Jan 1, 2001

Many mining operations are uncertain of what costs they should be achieving. The majority of cost estimates are based on historical costs that have added contingency factors. Historical costs are a valuable source of information but a more precise costing method is necessary. There are several alternative methods for predicting costs. A methodology which provides the best indication of the achievable costs is one using a standard inventory list and a bill of quantities. The model is termed a Basic Principles model and addresses basic design principles and engineering constraints.

Jan 1, 1990

By K. Y. Haramy

Coal mine bumps involve the violent, rapid failure of coal and rock around a mine excavation. Deep coal mines with strong roof and floor rocks and high-stress conditions frequently experience face and rib bumps. The bump problem is becoming more severe as mining depth increases, prompting efforts to control high stress in advance of mining. This Bureau of Mines report presents a review of the most widely used methods to detect and destress high-stress zones along coal faces and an investigation of stress-related bump problems and destressing techniques at a cooperating mine. Geotechnical instrumentation and microseismic methods were used to better understand bump occurrences in underground coal mines. Laboratory tests of the drilling-yield method for high-stress detection were conducted to determine the correlation between the volume of cuttings obtained and the magnitude of the applied stress at various confining pressures. A three-dimensional, multiple-seam computer modeling program, MULSIM, was used to evaluate the effectiveness of stress-relief methods. Modeling results indicate that dangerously high-stress areas can be controlled by either proper planning or destressing. Proper mine planning guidelines and destressing methods such as volley firing, hydraulic fracturing, and auger drilling are discussed.

Jan 1, 1988

By Thomas C. Anderson

Thirty-four retaining walls are part of the $46 million upgrade of a 1942 depressed highway in Highland Park, Michigan near Detroit. This project will close a missing link between two newer roadways, I-75 and the John Lodge Freeway. The existing 75 ft. wide, six lane Davison Freeway is being replaced by a eight to ten lane, 200 ft. wide depressed highway in a limited right of way. The highway will be 20-25 ft. deep and 1.5 miles long. A design/build decision by the Michigan DOT saved about 37% of the engineers estimated cost of $19 million for the walls. The successful pre-qualified specialty contractor utilized an innovative solution for the walls consisting of tiedback/cantilevered walls on the north side and mechanically stabilized earth walls on the south side. All of the walls have an identical cast-in-place architectural facing.

Jan 1, 1999

By R. Blickensderfer

Maintaining an adequate supply of minerals and metals to meet national economic and strategic needs is the overall goal of the Bureau of Mines, U.S. Department of the Interior. One method of achieving this goal is to conserve scarce metals by cladding a plentiful base metal, such as iron, with a scarcer metal. To investigate cladding, a vacuum-rolling mill capable of rolling bimetal specimens at temperatures to 1,300° C in a residual gas pressure of 2 x 10-5 torr was established. Metals that were successfully bonded to iron included stainless steels, chromium, nickel, nickel alloys, copper, and several refractory metals including molybdenum and titanium. The effects of the rolling temperature, reduction in thickness, rolling speed, and residual air pressure on bonding strength and bend ductility of the bimetals were determined. Optimum rolling conditions produced bimetals with bond shear strength essentially equal to that of the iron base metal.

Jan 1, 1980

By Pedro Lilienfeld

This report describes the development, design, fabrication and testing of a port-able, battery-operated, light scattering monitor (henceforth to be designated as ILSDM) for the rapid measurement of the concentration of respirable dust in mining environments. This instrument incorporates state-of-the-art design characteristics and makes use of advanced solid-state components both for light emission as well as for its detection. The use of a pulsed light source combined with synchronous signal detection minimizes drift problems and optimizes the sensitivity of the measurement. Simplicity of operation, reliability and ruggedness, light weight as well as improved performance were salient objectives of this instrument development program. Continuous clean-air flow screening of all critical optical surfaces, and optimized optical detection and electronic signal processing design resulted in about a hundred-fold decrease of noise and drift with respect to precursor instruments. Equivalent mass concentration measurements 88 low as 10 micrograms per cubic meter can be routinely performed with time constants of about 2 second.

Jan 1, 1979

The gold salting fraud at Busang on the island of Kalimantan, Indonesia was exposed in early 1997 and resulted from the independent drilling, sampling and assaying of PT Freeport Indonesia which reported assays from the South East Zone with negligible concentrations of gold. Since then, a number of legal actions directed at former Bre-X directors, consulting firms and financial or broking institutions are at various stages and are based on numerous allegations surrounding the supposed existence of obvious and numerous warning signs or æred flagsÆ. These include: the absence of references to visible gold in the drill logs; the alluvial nature of the gold grains; the high gravity recoveries; the invalid comparison with Kelian; the absence of outside scrutiny and the lack of external review/audit and surface depletion of gold. The focus on the red flags has been at the expense of the numerous positive indications or ægreen flagsÆ. These include the morphology and chemistry of the gold grains, the gravity testwork, the amalgamation results, the role of external consultants, the results of a review by one of North AmericaÆs leading minerals auditing groups, the behaviour of the gold at surface and the presence of references to visible gold in the drill logs. The flawed nature of the discussion of the technical facts surrounding Busang has prevented a meaningful and informed discussion about what actually happened and has, therefore, prevented the formulation of meaningful remedies for the future.

Jan 1, 2002

By D. D. Munro

Finsch Mine is a kimberlite diamond mine located at Lime Acres in the Northern Cape Province of South Africa. The mine was founded in 1961 and started surface mining in 1964. Underground production commenced in 1990 using a modified blast-hole open stoping method for the mining of Blocks 1, 2 and 3. Block 4 is currently being mined as a block cave. The process of identifying and optimizing a method to mine the Block 5 orebody started in 1991, and in 2006 incline caving was identified as being technically feasible. This paper aims to document the process employed in developing this method by the Block 5 prefeasibility team as well as discuss the technical challenges encountered during this process. The paper commences with a history of Finsch Mine and highlights the complex geology and threat of sidewall failure that prompted the decision to use block caving as the mining method for Block 4. A literature study of mines that implemented mining methods upon which the incline cave was conceptualized is then presented. These practices were then used to form the basis for the designs on which the initial geotechnical modelling was done and built upon through an iterative process of modelling and design changes. The ventilation of the mining area, initial productivity simulation results, and the applicability of automation and comminution processes in the incline cave are also presented. The paper concludes with an investigation into some of the challenges of the mining method, and shows that that incline caving is a technical option available for further investigation in determining the optimal mining method to be employed at Block 5, Finsch Diamond Mine. Keywords massive mining, incline caving, geotechnical modelling.

Jul 1, 2013

By Marcus Nadler

WAGES in the United States, in spite of the wage freeze, have increased materially. Overtime payments have become standard practice in almost all industries. Now efforts are being made to place wages on an annual basis, and if this is adopted, it will result in an increase in the cost of production. Organized labor today is more powerful than ever before; union membership is large and steadily increasing, and in many instances membership in the union is a prerequisite to employment. The treasuries of many unions are strong as a result of the large membership and full employment. The unions, therefore, today are in a much better position than ever before to carry on long strikes. Politically, too, the unions are more powerful today than they ever were. On the basis of their strength, one may expect that some of the demands that the labor unions will make in the not distant future will be granted. It is, therefore, quite evident that before long, particularly when the curtailment in war production reaches about 40 per cent, this country will be confronted with a serious labor problem.

Jan 1, 1945