Search Documents

By A. Kijko, C. W. Funk

Methods for the analysis of seismic hazards in mines are reviewed as illustrations of the techniques that are being used in some South African mines. The classical parameters that describe a hazard are the seismic activity rate, ?, the Gutenberg-Richter value, b, and, occasionally, the maximum regional magnitude, mmax The activity rate is calculated readily owing to the inherent simplicity of its definition. The evaluation method presented for the Gutenberg-Richter b value takes into account the presence of mmax Three statistical procedures are described for the assessment of mmax which the maximum observed magnitude, Xmax a crucial role. Often, the configuration of mine seismic networks is changed, or the networks are improved, which inevitably gives rise to changes in the completeness of the seismic catalogues. The routine analysis of seismic hazards must account for these time dependent changes. A method for the evaluation of hazards is reviewed that accommodates varying levels of quality in the catalogues. Finally, the concept of the volume of ground motion (VGM) is presented. This is a technique that allows for most aspects of seismic hazards in mines. The advantage of the VGM is that a hazard can be described by one physically significant value: the volume of rock (cumulated over a time period) in which the ground motion exceeds some critical particle velocity. Data from the gold mining region in South Africa known as the Far West Rand is used in a demonstration of the discussed methods of hazard analysis.

Jan 1, 1994

"Butte is in many ways an ideal location for a mining school. The student lives in the atmosphere of his intended profession. By the time he has spent four years at the school and in the community he has a fairly clear idea of what kind of a business he is entering upon, and is freed from any illusions about its being a primrose path he is about to follow. The mines and mills and smelters are his lecture rooms in part, and the shovel, pick and drill form part of his equipment. Most of the students work in the mines during part of their school life, which serves the double purpose of assisting them financially and increasing their practical knowledge.The School of Mines is a state institution, amply endowed and exceptionally well equipped. The school is strictly technical and no attempt is made to prepare men for any other work but mining engineering. The mining men of the community take an active interest in the welfare of the school and are of much assistance in securing employment for its graduates.The teaching staff is entirely composed of men who have had practical, commercial experience in their various specialties, and no expense is spared in securing suitable men for the faculty."

Jan 1, 1913

By Wang Xuguang, Zhang Xiaozhi, Li Guozhong, Xiong Daiyu

The emulsion explosive is a new kind of water-based industrial explosives that was developed at the end of 1960s. In the 1970s, BGRIMM invented EL-series emulsion explosive that created a new era of water-based industrial explosives technology and products in China. From single type to varieties, the perfect BGRIMM emulsion explosives technology has been formed, which consists of 9 series, over 30 types explosives and related production equipments and processes such as cap-sensitive rock emulsion explosive, opencast emulsion explosive, coal permitted emulsion explosives, low-temperature-resistant emulsion explosive, high-temperature-resistant emulsion explosive, high power emulsion explosive, bulk emulsion explosive for loading truck and powder emulsion explosive. From the early 1990s, BGRIMM successfully developed opencast emulsion explosives and the computer controlled continuous production line of small-diameter cap-sensitive emulsion explosive which raised emulsion explosive production technology of our country to a new lever. With the successful development of powder emulsion explosive and related computer controlled continuous production line, on-site mixed emulsion explosive and loading truck as well, the category of industrial explosives is getting more complete and reasonable. This paper pres ents the history, achievement and development of BGRIMM emulsion explosive technology, also forecasts the future of linked technology.

Jan 1, 2003

By Deepak Bhadouriya, Saurabh Singh, Aditya Raj Suman

"An experimental study of chemically enhanced filtration and dewatering of fine coal slurry with and without additives was carried out. The experiment involved determination of effect of slurry concentration, additives (cationic, anionic and nonionic), filter area, filtration velocity, particle size and cake resistance on dewatering and filtration using vacuum filtration cell. Finally, the rate of filtration and dewatering and optimum amount of additives used were determined under suitable filtration condition. Overall, it was found that the filtration and dewatering characteristics were enhanced by increased slurry concentration, larger filter area and larger particle size. In addition of additives, the kerosene was found to be best for enhancing the filtration which yielded cake moisture reductions of approximately 17% by weight. At optimum dosages, the final cake moisture contents were reduced by 3.6% and 5.8% by weight using the appropriate surfactant and flocculent, respectively.INTRODUCTIONFor India, it is estimated that coal constitute a principal source of energy for the next several decades. It is majorly used at thermal power plants to generate electricity and also to a great extent in steel and cement industry. It has been observed that its consumption is increasing so as to meet the energy requirements of the country. It has been found that in a coal preparation plant; approximately 20-25 percent coal is of the mined coal of the range below minus 0.5 mm (28 meshes). Generally, this fine fraction is discarded due to its high cost of processing and further utilisatisation is very minimal. But with ongoing research and development for advanced clean coal technology, various new techniques have been evolved to maximize the utilization of available coal. In recent time technologies such as column flotation, cleaning of fine size coal to lower the ash content and low pyretic sulfur is feasible at high recovery value. But in various researches it is found that one of the biggest hurdles in utilization of fine coal cleaning technology by the coal industry is the economic dewatering of the fine clean coal product. Thus, until an economical and practical solution to dewatering of fine clean coal is achieved, the efforts devoted to developing fine clean coal technology will be wasted. In this paper an effort toward enhancing and developing the optimum technique of dewatering and filtration of fine coal slurry has been made."

Jan 1, 2016

By Thomas V. Falkie

The purpose of this work was to investigate the rate at which coal is delivered from the underground working face by gathering arm type loaders as employed on continuous mining machines, to identify the factors -- geometrical, geological, mechanical, or procedural which affect the delivery rate, and to develop quantitative rate descriptive equations for the loading function. The mathematical techniques employed were factor analysis and multiple linear regression. It was determined that the coal-cutting function of the continuous mining machine is the factor that primarily influences the loading function. The geometrical factors -- the dimensions of the work area in relation to the dimensions of the mining machine - were the factors of secondary influence. Fifty-five percent of the experimental variation in the loading function was explained in terms of the six most prominent independent variables. It is expected that this work will be useful in operations-research studies as applied to underground coal mining, and with refinement will enable mine planners to select equipment based on the operating characteristics of the equipment and the mining conditions.

Jan 1, 1972

By Edward J. McNamara

Sulphur as an element has been used for centuries. The technique of storing, handling and transporting it in its various forms has changed through the years. Freeport Sulphur Company, a division of Freeport Minerals Company, has produced sulphur since 1912. The first storing and transporting of this product as a liquid began in 1947. Significant environmental problems occurred in the handling of solid sulphur in the late fifties and early sixties. Since the sulphur WAS produced in the liquid form and the major customers used it in the liquid form, it became obvious that a liquid transportation system was the solution. The liquid sulphur delivery eliminated the dusty and hazardous handling problems and the contamination of the sulphur by dirt, acid, moisture and other materials. The remelting by the customer to use the sulphur is thusly eliminated with a savings in energy. In addition, this change in the mode of handling permitted a broad development of new sulphur mines in the marshy coastal area of Louisiana and offshore in the Gulf of Mexico.

Jan 1, 1978

By Donald E. Scheck, Da-Rong Chou

The application of geostatistics to coal reserve analysis is discussed. One problem in particular, the selection of the optimum locations for exploratory drill holes, is considered in detail. A new interactive program to help the geologist determine the best locations is described and applied to a specific property. The steps in the process are described and then illustrated using a mine's actual data. First, a variogram is selected based on graphical displayed information from the known sample data. Kriging estimates are made for the region of interest and the blocks within the region. The location of future exploratory drill holes is selected based on the criterion of minimizing the region estimation variance for a given number of exploratory holes. The least number of exploratory holes required to meet a specified upper limit on the regional variance is also determined. The computer generated recommendations for the exploratory drill holes are compared to a manually prepared drilling plan. The post- drilling analysis of the results is compared to the predicted values.

Jan 1, 1983

By Ricardo Burdisso, Rahul Kadam, Kyle Schwartz, Marty Johnson

Occupational exposure to hand transmitted vibration (HTV) arises from the hand held powered tools extensively used in the mining and construction industry such as rock drills, chipping hammers, chain saws etc. Regular exposure to HTV is the major cause of a range of permanent injuries to human hands and arms which are commonly referred to as hand-arm vibration syndrome (HAVS). In addition to this, the percussive tools generate overall sound power levels in excess of 110dBA in most cases. Such a high sound power level greatly exceeds the maximum permissible exposure limit (PEL) of organizations such as National Institute for Occupational Safety and Health (NIOSH) and the Occupational Safety and Health Administration (OSHA). Long term occupational exposure to this noise has been diagnosed as the main reason for permanent hearing loss in the operators. It is therefore important to develop an understanding of the mechanisms which lead to these high vibration and sound levels and in order to do this a detailed computational model of a pneumatic chipping hammer has been made. This paper presents a nonlinear computational model of a pneumatic chipping hammer. In order to better understand the dynamics of the chipping hammer, the hammer was subdivided into components that are shown in figure 1 (a) (based on a chipping hammer manufactured by Atlas-Copco). The hammer mainly consisted of a center body, a moving piston and a chisel. Compressed air is used to drive the piston inside of a cylinder and on the downward stroke this piston impacts the chisel to create the hammer effect. The machine has one pneumatic valve and this valve regulates the air supply either to the upper chamber or to the lower chamber. The valve changes according to the relative pressures in the two chambers and the supply pressure. There are also twelve different exhaust ports at two positions along the cylinder labeled upper ports and lower ports. As the piston moves the ports can be closed or open (allowing exhaust). Fundamentally, the computational model was made up of two different sub-models, a fluid model and a structural dynamic model as shown in Figure 3 (a) and (b) respectively. The first sub-model takes into consideration the fluid dynamics of the machine since the hammer is driven by compressed air. Equations for the mass flow rate though bleed orifices (assuming an isentropic process) 1 is used to determine the mass flow into and out of the upper and lower chambers. From this the pressures in the two chambers and consequently the forcing on the piston can be calculated. The second sub-model deals with modeling the structural [ ]

Jan 6, 2006

By Gerald C. Smith

Introduction Newmont Mining Corp.'s Carlin Gold Mining Co. mines gold ore and waste material from four open-pit mines in Northeastern Nevada. Combined production rate is 24.5 Mt/a (27 million stpy). The company is producing gold bullion from the 2.4 kt/d (2600 stpd) Carlin Mill No. 1. and the 2.3 kt/d (2600 stpd) Maggie Creek heap leaching plant. In August 1985, the 6.3 kt/d (7000 stpd) Carlin Mill No. 2 at Gold Quarry came on-line. The total combined throughput of 11.2 kt/d (12,000 stpd) will make Carlin Gold Mining one of the largest US gold producers. Feasibility studies are underway to increase the total gold out-put from Gold Quarry. This will be done by adding a continuous dump-leaching process that will recover gold from lower grade ore. History In 1961, Newmont exploration geologists located claims in the Lynn Creek mining district near Carlin, NV. An exploration drilling program revealed significant gold mineralization. A stepped-up drilling program revealed an ore body with an estimated 10 Mt (11 million st) of ore containing 109 t (3.5 million oz) of gold. Test results in 1963 allowed metallurgists to develop the flowsheet and design for a 1.8-kt/d (2000-stpd) countercurrent decantation (CCD) cyanide plant. Carlin Gold Mining Co. was formed to operate the property. Carlin purchased its first mining equipment in 1965. This consisted of two Bucyrus-Erie 2.7 m3 (3.5 cu yd) shovels and nine 27.2 t (30 st) Wabco Haulpak trucks, two Inger¬soll-Rand track-mounted drills, one Chicago Pneumatic T-650 rotary drill, one rubber tired Michigan 280 dozer, one Caterpillar D-8 36A track dozer, one Caterpillar 16 motor grader, and the necessary ancillary equipment. The fleet was capable of mining 3.2 Mt/a (3.5 mil¬lion stpy) working two eight-hour shifts, five days a week. In 1967, one P&H 1500 3.8 m3(5 cu yd) diesel electrical shovel and three 59 t (65 st) Dart trucks were added to the fleet, along with a Chicago Pneumatic rubber tire mounted rotary drill. This equipment addition increased the mining capabilities to 5.7 Mt/a (6.3 million stpy). Three separate pits, the Main, East, and West, within a 1.6-km (1-mile) radius of the Carlin mill were being mined. The crew consisted of 46 hourly men and three supervisors. This equals 497 t/ total hourly manshift (548 st) or 407 t/total manshift (515 st). Rising gold prices in the early 1970s allowed lower grade deposits to be mined at greater distances from the mill. The Boot-strap pit, 19.3 km (12 miles) north of Carlin, was started in 1973. Two Hough 45.4 t (50 st) front-end loaders, four Wabco Haulpak 45.4 t (50 st) trucks, and a second track type D-8H dozer were added. The higher grade ore was trucked to the Carlin mill using three

Jan 11, 1985

By Henry Chumienski

Next to the paper industry, the steel industry is a major user of water. Without an adequate and reliable source of “good” water, steel cannot be produced. The use of water has a direct impact on steel quality and on our environment. Used improperly, water can also add unnecessary costs. Used properly, water can maintain and improve steel quality, enhance our environment and control or reduce the “total cost of operation”. Water needs to be more than just “wet and not lumpy”. Water quality needs to be based on the end use. This paper discusses ways to manage many of the water systems. With little or no capital investment it is possible to develop operating practices that protect your initial investment, ensure that the water systems do not have a negative impact on quality or your production costs and also minimize your chance of having an environmental incident.

Jul 30, 2018

By Timothy W. Ellis

Gold-based materials have been a mainstay of the electronics and semiconductor industry since the physics was just a laboratory curiosity. Gold is the workhorse material in wire bond, flip chip and off wafer interconnections due to its corrosion resistance, ability to form metallurgical bonds by soldering or cold welding, and ease of fabrication. As the electronics and semiconductor industries grew, so did the use, of Gold in spite of the feature size reduction so elegantly demonstrated in Moore?s law. However, several revolutions in the Silicon miracle are threatening Gold?s place as the material of choice. Although cost is always an issue, the limitations are associated with the chemistry of Gold based alloys. Will Gold remain? Emerging requirements of bioelectronics, photonics and power requirements in conventional device represent new opportunities for Gold to shine. Additionally, as the world market demand for electronic, semiconducting, bio-electronic and photonic technology increases, given the right technology, Gold still can provide value proposition.

Oct 1, 2003

By U. F. Beichmann

INTRODUCTION The City of Oslo together with the neighbor municipalities, Baerum and Asker, are presently building a jointly owned sewage treatment plant located on the west side of the inner Oslofjord. The project is scheduled for completion late 1981. Because the location of the treatment plant is at a distance of about 20 miles (30 km) from the city center, a discharge of more than 13 yds 3/sec (10 m3/sec.) of sewage and storm water will have to be transported over considerable distances. The topography of the area and the geological conditions early indicated that the only realistic transport method had to be through tunnels. As planning proceeded, full face tunnel boring emerged more and more as a favorable alternative to conventional drill and blast medhods. Today the scheme comprises nearly 25 miles (40 km) of tunnels being excavated by full face tunnel borers. In addition a number of access tunnels and cross cuts are to be excavated by conventional methods.

Jan 1, 1979

By Robert L. Bates

United States production of the industrial minerals, ahead of that of the metals since 1946, has shown a steady and rapid growth. By 1963, their value was more than twice that of the metals. Yet papers on the metallic ores continue to dominate the meetings of the Society of Economic Geologists and constitute nearly nine-tenths of the lead papers in Economic Geology. Most of the geological communication that does take place concerning the industrial minerals deals with high-value special-purpose minerals, which are comparable to the metallic ores in geologic complexity. The large-bulk rock products, which are growing fastest in production value, are characterized by relatively simple geology and by thousands of small producing firms, many of which do little or no geological work. The need for geological advice by this very large segment of the industry is bound to increase. In the meantime, a plea is made for more geological communication among those concerned with the industrial minerals of all varieties.

Jan 1, 1966

By L. W. Casteel

St. Joseph Lead Company's Southeast Missouri mines have been successfully converted to the use of ammonium nitrate and fuel oil as a blasting agent. This is significant to the company because it means a savings of a quarter of a million dollars per year. It is significant to the mining industry because of the unusual conditions involved and the methods and materials used to overcome them. St. Joe has been mining the low grade lead deposits of southeast Missouri since 1864. This ore occurs as disseminated galena in widely scattered pockets within the Bonneterre dolomite. The daily production of 20,000 tons is obtained from several hundred small, room and pillar stopes covering an area 10 miles long and five miles wide. Distribution of explosives and other materials is a real problem. Drilling in the stopes is done with air legs, column- mounted machines or jumbos, depending on the size and location of the stope. Drill hole sizes vary from 1 3/8-in. diam down to 1 1/8-in. Each driller charges his own holes and shoots them at the end of the shift. Numerous shafts provide natural ventilation which is supplemented in isolated areas by churn drill holes equipped with blowers. Water, in most stopes, is not a serious problem, although the mines do produce about 20,000 gpm.

Jan 5, 1962

By Joseph Meyers

Explosives techniques and technology are constantly evolving and improving, yet basic communication and business skills are not being used regularly. Many potential blasting projects never occur due to simplistic, basic factors, such as a lack of communication. Articulate communication is the key component in the blast approval process, which has changed remarkably from how business was conducted fifty years ago. Imperative to the approval process is communication outlining the safety and benefits of the blasting project. Information and transparency with the stakeholders and the Authority Having Jurisdiction (AHJ) will greatly improve the chances of having a blasting project approved. This open communication starts at the inception of the project when the memorandum of understanding (MOU) is obtained, and involves the AHJ through all steps of the approval process. The blasting industry and regulators must work collaboratively to improve safety, security, regulations and licensing. Implementing state of the art blasting techniques, security, safety measures, vibration monitoring and strict licensing allows the AHJ and all stakeholders to remain integrated and informed, contributing to process approval. Regulatory operators should strive to achieve success thru communication, cooperation and compliance which is accomplished thru continued education and transparency. These steps, combined with regular meetings, has proven to be a benefit to both industry and regulators. Relationships are built through trust, teamwork, transparency and communication –including the take holders and AHJ in the approval process from the inception solidifies these relationships and improves teamwork

By A. M. El Shafey, Ahmed W. Hussein, Ibrahim M. Gaafar, Mona M. Fawzy, Mohamed Diab, Mohamed S. Abu El Ghar

The Quaternary stream sediments of the Diit area, southern Red Sea coast, Egypt, were mineralogically studied for their content of economic heavy minerals. The study area covered approximately 450 km2 and included three main parts: Wadi and Delta Diit, as well as Diit lens. The mineralogical investigation revealed that these sediments contain considerable amounts of placer ilmenite, magnetite, zircon, sphene, apatite, garnet, and rutile. Also present, in minor or trace amounts, are uranothorite, monazite, xenotime, fergusonite, khatyrkite, and gold. The magnetic fractionation tests, supplemented with the XRD and SEM mineral analyses, indicated the presence of Fe-oxide minerals as wuestite, hematite, and maghemite accompanied with magnetite as products for hand magnet separation. Ilmenite separation was carried out using a high intensity magnetic separator at a current of 1 A, while the paramagnetic minerals (e.g., garnet, pyroxene, amphibole, epidote, monazite, xenotime, and fergusonite) were separated as magnetic fraction at a current of 3 A. The non-magnetic minerals (e.g., zircon, apatite and rutile, uranophane, uranothorite, gold, and khatyrkite) were obtained at 3 A current. On a mineralogical and geochemical basis, the present work suggests that Diit stream sediments should be considered as a potential source for Ti, Fe, Zr, Zn, and Cu after the physical upgrading processes for concentrating the minerals carrying the aforementioned economic elements.

Jan 21, 2022

By A. B. Cecala

The US Bureau of Mines performed a study to determine optimal locations for longwall face methane monitoring equipment. Longwall face ignitions continue to be a concern to the US coal mining industry. Gains in ignition control technology have been somewhat negated by advances in longwall productivity. More reliable, heavy duty longwall face systems generate higher production rates and increase methane liberation rates. These rates will likely continue to rise as further coal production increases occur. Efforts will continue in the areas of methane drainage, methane containment and methane dilution. In addition, more effective face methane monitoring is needed. As technology continues toward automated longwall panels, the importance of monitoring for methane at the shearer becomes even more significant. Since the primary face ignition source is the shearer mining machine, the Bureau ran tests to determine the best location to take methane readings on the shearer. This information, in conjunction with data obtained from field studies, provides a knowledge base for selecting optimum face methane monitoring locations.

Jan 1, 1995

By Bond W. F, Sharry P. V, Onley P. G

The use of Decision Analysis is becoming more widespread in industry as a whole, and there is considerable scope for its application in the mining industry. Wherever decisions have to be made, whenever risks have to be taken, whenever uncertainty exists or whenever judgements have to be made, then Decision Analysis can be used. In the mining industry we daily make many decisions involving risk, uncertainty and judgement. Expansion and diversity will only increase the need for balanced decision making techniques. This paper seeks to describe the history and principles of Decision Theory, and to illustrate the various modelling approaches using three fictitious yet realistic case studies. Decision Analysis logically integrates the quantifiable and seemingly non-quantifiable aspects of a decision problem into a coherent, explicit and rational solution. It also allows the decision-makers to see the full impact of each variable or uncertainty, and hence focus on the key aspects that influence the solution.

Jan 1, 1996

By Tim Robinson, Georges Houlachi, Michael Moats, Marco Ginatta, Michael Free, David Creber, Neale Neelameggham, George Holywell

"Electrolytic processing is used commercially to recover and/or refine metals such as aluminum, copper, magnesium, nickel, and zinc. There are also new and exciting opportunities to utilize electrometallurgy in the production of titanium, lead, and other metals. This paper reviews some of the main technologies that are used to produce and refine metals as well as some of the recent advances and future directions the electrometallurgy industry may implement to meet the challenges faced now as well as those that are likely to be faced in the future.IntroductionElectrolytic processing is used commercially to recover and/or refine metals that include large scale production for metals such as aluminum, copper, magnesium, nickel, and zinc as well as small scale production for metals such as gold and silver. There are also new and exciting opportunities to utilize electrometallurgy in the production of titanium, lead, and other metals. This paper will focus only on electrometallurgical processing of metals with relatively large production markets."

Jan 1, 2012

By S. G. Mgenge, J. D. Steenkamp

Tronox Namakwa Sands operates two ilmenite smelters for the production of high-titania slag and low-manganese pig iron. Slag or metal is tapped from one of two product-specific, bi-level tap-holes. In this paper the refractory design specific to the tap-hole refractory layout is described, as well as practices for slag and metal tapping and refractory maintenance. Further developments planned are briefly described.

Jan 1, 2014