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By Wen L. Cai

This paper examines the effects of different block dimensions and cone bases on the economic open pit limit design based on case studies on a coal deposit consisted of two west- east elongated, near vertical thin seams starting with a base model dimension of 200x170x50 (NX*NY*NZ) with a block dimension of 10mx5mx4m (DX*DY*DZ), the blocks were combined along easting, northing and elevation directions. Two cone bases were used, one with a base radius of 10 meters, the other with a base radius of 0. Two pit design algorithms, one is the floating cone algorithm, the other is an optimum algorithm, were used to see which one of the two pit design algorithms is more sensitive to block dimension and cone base variations. The results are presented and analyzed.

Jan 1, 1992

By Mark Gershon

This paper describes an application of a new approach to mine planning and production scheduling in a gold mine. The technique, limited to use in open pit mines (but not limited to gold), has been described previously (Gershon, 1987). The-computer program used is the HOPS software, which has been described previously as well (Gershon, 1988). The mine is scheduled for the production of 8,000 blocks out of a mine having 25,000 blocks (50 x 50 x 10). The technique is based on the concept of inverted cones (Gershon, 1987). While it does not provide a true optimization of results, it does approximate the optimal situation. As opposed to most scheduling software that only serves as a computerized notepad for the scheduler, the use of this approach allows for a scheduling intelligence to be built into the software.

Jan 1, 1989

By Peter B. Knuckey

1, Introduction Location Kalengwa mine is located in the North Western Province of Zambia, 402 kilometre by unpaved road to the west of Kitwe, which is roughly in the centre of the Zambian Copperbelt, well known as one of the world's centres of copper mining. Its position is illustrated on the map of Africa in Figure 1 and on the map of Zambia in Figure 2. It is a mine of Roan Consolidated Mines Limited whose other properties, Mufulira, Luanshya, Chambishi and Chibuluma Mines, are all located on the Copperbelt. It is managed by the Chibuluma Division of the company. The rate of production from Kalengwa will vary from 12 000 to 17 000 tonnes of saleable copper a year over the next six years. Kalengwa did not exist as a place until the first prospecting parties and later the mine became established and the early working population was recruited entirely from small villages in the surrounding area as much as thirty miles away. The mining area consists of fourteen mining locations amounting to 3.35 square kilometres and the land may be used for any purpose connected with mining, including housing, wood cutting and other utilities. The whole area is, except for minor undulations, a fairly flat plateau with main rivers running from north to south and flood basins known as "dambos" located in a general east west direction. Vegetation is, with the exception of the grassy dambos, temperate forest with relatively light undergrowth. Game of great variety is prolific, as is the associated tsetse fly.

Jan 1, 1971

By Henry H. Rubin

Rubber and its contributions to the economic solutions of environmental problems in the minerals industry. The intelligent applications of "Rubber" to systems of noise abatement, vibration isolation, dust containment, weak and corrosion resistance has proven economically beneficial. Intelligent application requires a thorough understanding of the nature of the material, knowledge of the process wherein it is going to be applied, and consideration of the environmental conditions in which it will serve, for these determine the proper amount, type, compound and configuration for an economically successful application.

Jan 1, 1979

By Daniel A. Payne

For many years underground mining in the Sydney Coalfield has suffered from the effects of high horizontal stresses. It is only in the last 15 years that they have come to be recognized, understood, predicted and even avoided. This paper relates experiences in three coal mines in three different seams in the Sydney Coalfield. The effect of the direction of the principal horizontal stress on the direction of drivage of gate roads, access roadways and longwalls is described. Results of a monitoring program to measure the change of magnitude and direction of the principal horizontal stress in the gate roads as a result of longwall mining are also presented as well as the effect of the direction of principal horizontal stress on the shape of sandstone/gas outburst cavities.

Jan 1, 1998

By Roy A. Grancher

?The Horn of Plenty seems to have sprung a leak?.? anonymous For the first time in the Nation's peace-time history, shortages have become a way of life for the United States. Such words as scarce, tight, and critical are used in regard to supply, leading to priorities, allocations, and possible rationing as make-shift attempts to satisfy demand. Almost every day a new type of shortage appears in another product area that has traditionally been taken for granted as being in perpetual abundance. The range of coverage extends from basic commodities such as oil, chemicals, cement, steel, copper, cotton, etc., through to machine tools, motors, bearings, electronic components, etc. , to those finished outputs that satisfy our fundamental requirements for food, clothing and shelter. Signs of the times appear in cancelled airline flights, unfilled lines at gasoline stations, no available home freezers, lengthy delays in any furniture deliveries, or to that little old lady seen walking out of a local supermarket clutching her hoard of twenty rolls of toilet paper. What a sad commentary to have to make about our Land of Plenty, so long the envy of the World for its material wealth -- and today with its initials "U. S." seemingly standing for ?Unlimited Shortages.?

Jan 1, 1974

By Jr. Flynn

The filtration process has long been utilized in the mining industry and typically associated with processes where clear solutions are required. One definition of filtration states that it is utilized to affect a more complete separation of liquid and solid phases than is possible with settling alone. The development of Diatomaceous Earth filter aids has added a new dimension to filtration technology in the mining industry. It makes possible the filtration of slimes with almost perfect clarity, and at rates that become economical.

Jan 1, 1980

By Robert A. Bauer

Investigations of bedrock within subsided areas over abandoned coal mines reveal) very little disturbance of the bedrock. In areas that have surface subsidence of .3 to 1 m (1.0 to 3.25 ft), examination of cores from exploration drilling and investigations of the boreholes by means of closed circuit television have shown that fractures are spaced at least .9 to 3.6 m (3 to 12 ft) apart and are located within a zone 6 to 15 m (20 to 50 ft) above the collapsed area in coal mines 42.6 to 112.7 m (140 to 370 ft) deep. The dip of the fractures ranges from 25 to 60 degrees, cutting across nearly horizontal sedimentary bedding planes. Typical core recovery is 80 to 95 percent within the subsided areas and 100 percent outside the subsided areas.

Jan 1, 1984

By G Luxbacher

Computer simulation of mine ventilation systems is rapidly becoming an essential tool in mine planning and design. This paper examines the utilization of ventilation simulation techniques to evaluate the number, shape, size and layout of mine entries in a typical coal mining system. Since the mains and sub-mains serve mainly for transportation and ventilation and the ventilation system is critically important to the health and safety of the workers, there exists a great need for optimal designs in this area. Evaluation criteria, could include, among others, minimization of power costs, shaft requirements and leakage. Constraints of this optimization problem include health and safety regulations and production and mine infrastructure requirements.

Jan 1, 1977

By Dan S. Nilsson

When an open pit mine is deepened, more and more waste rock must normally be removed. Techniques for optimization of open pit design are well-established within the mining industry. The recommended method is to choose the open pit alternative with the highest net present capital value of open pit and future underground mining. When the open pit is mined out, the operation must be closed, or, if it is profitable, mining must start underground. When planning an underground operation we experience the same type of optimization problem that occurs when determining the optimal depth for open pit mining. When mining underground the ore body is often divided into a number of areas, blocks or slices, each containing a transportation system with trains, trucks, conveyors, etc. When all the ore within such a part of the deposit is extracted, the operation must be closed, or, if it is profitable, a new transportation must be developed. The question that now arises is: how large a pan of a deposit shall be included in the first development and how much shall be left for future consideration?

Jan 1, 1981

By Nicholas S. Lynn

Introduction Borne out of the need for reductions in capital expenditure and increased production, several new and innovative carbon systems have been developed for small precious metal heap leach operations throughout the United States. Perhaps the most important aspect of these systems is the carbon column. Though diverse in design, these columns can be categorized into three basic types. The first is known as the gravity flow type or Cortez type. As the name indicates, solution flows via gravity, throughout 4 to 6 columns which are arranged in a normally stepped con- figuration which is conventionally upflow in design. The second type, known as the vertical column, is an arrangement whereby flow is established through pressurization in an upward manner, throughout 4 to 6 columns in a vertically stacked configuration. This arrangement is typically intended for use with small portable heap leach operations and employs a semi-continuous mode thus preventing gravity from occurring. The third type and newest development in carbon columns is an arrangement whereby the solution flows throughout 4 to 6 columns placed in a side by side configuration and pressurized by a single feed pump (Figure 1). A unique aspect to the third type, is that the adsorb and desorb cycles are accomplished in the same column, due to a fixed carbon charge. An in-depth analysis is warranted due to numerous advantages of this arrangement, and is therefore the subject of this paper. Advantages and Variations One advantage to the third type of carbon column is the fact that initial capital expenditures and operating man- power requirements are reduced. Another advantage is that the system can be made fully portable up to a 0.0315 m3/s (500 gpm) capacity. Systems of this nature are operational at several sites. Above this flow rate, the system's portability is one which can be maintained, but disadvantages (i.e. larger diameter carbon column and greater weights) far outweigh the advantages. There are several variations in each of these systems which allow for unique operation. For example, carbon columns made highly portable, can be moved from unitized heap leach operations to central stripping facilities. Although this method has been used in Colorado, transportation of these units has been known to be quite cumbersome. If distances exceed 5 km (3.2 miles) then special front-end loaders are required. This limits heap locations to within 5 km (3.2 miles) of the central processing facility. Another example transports the carbon charge from the heap leach locations to a centralized processing facility; this method is quite effective. For the past 5 years one mine has employed this technique of transporting carbon in 907 kg (1 ton lots), in DOT containers, towed by company pick-ups. This operation uses a vertical column with a 907 kg (1 ton) carbon charge. A third example uses static carbon columns with fixed carbon charges. Carbon Adsorption System The carbon adsorption system (Figure 1) is fed by a single preg solution feed pump. This feed pump pushes the preg solution through all four to six fixed charged carbon columns, which are on line. The sequencing of the carbon columns is achieved using valves. Expansion of the carbon charge is dependent upon the carbon selected. The carbon typically used is a 6 x 12 mesh size, with a nominal flow rate of 0.00135 - 0.00138 m 3/s (22-25 gpm) per square foot of carbon, based on a 40% bed expansion. With 8 x 16 mesh size,

Jan 1, 1987

By J. G. Smith, L. P. Sheets

Introduction Potential applications that exploit the electrical properties of coal measure rocks include: (1) radar sensing of coal face, floor, and roof for automated mining operations; (2) underground wireless communications; and (3) sensing extent of subsidence, blasting operations, coal gasification bums, and moisture migrations. Impediments to exploitation of electrical properties include: (1) a lack of reliable electrical properties data for in situ conditions and (2) a lack of correlation data between electrical properties and other relevant physical properties. In this paper data are presented for electrical conductivity and permittivity for Appalachian and Illinois shales for a frequency range 2 x 10 to 2 x 10 Hz. These data are useful in establishing in situ electrical property variability, lower limits, and anisotropy. Electrical proper¬ties measurement and values for other coal measure rocks are discussed as well. Laboratory measurement For the frequency range investigated, a capacitance bridge and Q-meter were employed. These instruments are designed to yield bulk values of permittivity and conductivity. Disk samples of thickness 0.396 cm (0.156 in.) and diameter 2.54 cm (1 in.) were machined from cores obtained from the two coal basins. While both the capacitance bridge and the Q-meter must be balanced manually, the bridge has an analog-to-digital interface and an attached computer specifically designed to expedite data collection and interpretation. Sample holders are critical components in the measurement process. A Hartshom-Ward holder was employed with the bridge and a Marconi micrometer jig was used with the Q-meter. Neither commercial sample holder was designed to regulate ambient humidity conditions. Because water adsorbed on sample faces may cause errors approaching 100%, special enclosures were designed for both holders. Each enclosure contains a flush-mounted externally-manipulable carousel, an externally-manipulable rigid arm that can accomodate translational motion and three-dimensional rotation, a compartment for humidity regulating solids or liquids, and a humidity sensor. Each enclosure will accomodate several samples that can be manipulated within the enclosure without opening it. Experience gained during this research demonstrated that humidity regulation was necessary to obtain repeatable results. Grinding and polishing shale to a very thin thickness (about 0.4 mm) was shown to cause changes in electrical properties as well. These latter changes were attributed to alterations in the water content. Theoretical considerations A very comprehensive discussion of the electrical properties of sedimentary rocks is available in literature (Sen and Chew, 1983). These authors reviewed the work of others and proposed modifications to better explain the frequency dependent behavior of the permittivity and conductivity of rocks. A large portion of their article was devoted to explanations of large relative permittivities at low frequencies such as observed in this research. They noted that the electrical properties of formations containing shales and clays are the most difficult to explain. Sen and Chew noted the need for additional experimental data and further refinements in theory. Results Shales, limestones, and sandstones were examined for a single 150-m (492-ft) core from Pennsylvania and for a dark shale from a southern Illinois coal mine. Figures 1 and 2 illustrate the conductivities and relative permitivities for the southern Illinois dark shale at a single location. The differences in electrical properties clearly

Jan 1, 1987

By M. W. Smith

Pennsylvania has 2500 miles of streams that do not meet water quality standards due to acid mine discharge (AMD), making AMD the greatest cause of water pollution in the state. The problem is mainly caused by abandoned coal mines. Pennsylvania is using a watershed-based approach to abating AMD which includes remining as a key component of a comprehensive restoration strategy. The Tangascootack Creek Watershed was targeted for AMD restoration through remining. Geologic mapping and overburden data were analyzed using Earth Vision software to identify areas of coal reserves which could be remined to improve water quality. Incentives are offered to encourage mining in these designated areas.

Jan 1, 1999

By G. K. Hoffman

Humate, defined as weathered coal or mud-stone rich in humic acid (HA) and fulvic acid (FA) have been mined, primarily as soil amendments or drilling mud additives, in New Mexico for 15-20 years. The New Mexico humate resource is estimated to be 11 Gt, including weathered coal and organic mudstone. The HA and FA content determines the end-use, therefore a simple and consistent method of measuring organic-acid content was developed. The New Mexico Bureau of Mines and Mineral Resources method is based on repeated alkali leaching and acid precipitation. Precipitates of humate are ashed, with mass balance of solids maintained, to correct for material added during alkali-acid treatment. Analyses of upper coal member, Cleary Coal Member (Menefee Formation) and Fruitland Formation samples from the southeast San Juan Basin show ashing to be important in accurate analysis of FA content. Ash in the total FA fraction averages 70% compared to 2% in HA. The FA in weathered coal and organic mudstone are similar, although HA is significantly higher in the former. As weathering progresses, the FA content of weathered coal increases faster than in organic mudstone because of the greater total organic material in coal.

Jan 1, 1994

By J. Y. Kim

Lead ions originating from galena during processing of complex sulphide ores migrate to "cover" the surface of sphalerite and iron sulphide mineral particles, and cause poor selectivity in differential flotation. Generally in sulphide ore processing, the lead-activated minerals float in the Cu/Pb rougher circuit. Subsequently, surface lead complicates the zinc flotation circuit by lowering the concentrate grade due to the co-flotation of lead-activated iron sulphide minerals. The effect of lead in the differential flotation of sphalerite from Cu-Pb-Zn and Pb-Zn ores is discussed. Plant and laboratory test data are interpreted by determining the surface composition of individual grains of sphalerite and iron sulphide particles using two surface analytical techniques, Laser Ionization Mass Spectrometer (LIMS) and Time of Flight-Secondary Ion Mass Spectrometer (TOF-SIMS). Cationic and anionic species on the surface were analyzed to elucidate the phenomena.

Jan 1, 1995

By V. T. McLemore

The Steeple Rock district is a major epithermal .gold-silver district in New Mexico that exhibits district zoning. Five types of ore deposits occur in the district. The base-metal veins (with Au and Ag) form the center of the district and occur along the Carlisle fault. The gold-silver veins occur along northwest-trending faults outward from the base-metal veins. The margins of the district are formed by copper-silver, fluorite, and manganese veins. In addition, areas of older acid-sulfate alteration occur throughout the district and also exhibit zoning: massive silica/chert zone (inner), silicified zone, and clay zone (outer). This alteration overlies regional; alkali-chloride (propylitic to argillic to sericitic) alteration. Synthesis of available data suggests the acid-sulfate alteration is related to a shallow but older epithermal hot springs system. Subsequently, younger epithermal veins formed along faults.

Jan 1, 1994

By C. Sun

The Leeville underground mine has been in operation since 2006 and currently produces 3,300 tons of ore per day with an average gold grade of 0.4 opt. The mine has a large horizontal extent of 2,500 feet by 500 feet and a vertical extent of 20 to 200 feet. Based on the characteristics of the ore bodies, the deposits are divided into several mining zones. The geotechnical properties of mining zones are also different from one zone to another. A successful geotechnical collection system is very important for the mining designs and operations in the Leeville underground mine.

Jan 1, 2010

By Hans E. Tausig

The economics of transporting minerals by sea in less than full cargo lots encompasses an analysis of production costs, sale and inventory calculations and a careful comparison of ocean freight costs all of which when pieced together will usually definitively indicate which of the ocean freight alternatives is the correct one for the economic factors involved. To illustrate: Let us assume that a production to be marketed yields 60,000 metric tons of copper concentrates over a twelve month period. Shipment is geographically viable through Vancouver, B.C. The production has been sold to a Japanese Smelter and the mine produces at a rate of 5,000 metric tons of concentrates per month. The copper has been sold CIF FO. The Seller has carefully investigated ocean freight rates Vancouver, B.C./Hibi, Japan and finds that he could obtain a twelve month freight contract at $15.00 per metric ton FIGS based on a loading/discharging speed of 4000/ 2000 metric tons per WWDSHEX (weather working day, Sundays and Holidays excluded) this freight rate being predicated on shipping in lots of minimum. 15,000 tons. A further freight investigation reveals that to ship at the same terms and conditions but in lots of 5,000 tons, and shipping each month (in accordance with the mine's actual production) would cost $20.00 per metric ton FIOS. The calculation that is now made is whether it is more desireable to pay a higher ocean freight by shipping in 5,000 ton lots or to pay the lower freight where here the ocean freight involves a difference of some $300,000.00.

Jan 1, 1979

By Shuji Owada, Keisuke Yasukawa

Electrostatic and/or high tension separation has been used for the separation of rare metal bearing minerals, foods, industrial wastes and so on. Since the separation is achieved by the difference mainly in surface conductivity of particles, the efficiency in humid circumstances is very low, and then, the applicability is considerably limited. We applied the following two-stage pretreatment technique to the separation process, which involves (1) adjustment of surface wettability by adsorbing surfactant on the particle surface and (2) control of the surface conductivity by spraying with electrolyte aqueous solution. The addition of this pretreatment technique has been found to have a great advantage over conventional methods. Separation efficiency is achieved even in humid circumstances and selectivity can also be obtained between insulator minerals. The selectivity is very similar to that of flotation in wet process. This separation technique will be applied not only to mineral processing but the processing of industrial waste such as electric and electronic waste materials.

Jan 1, 1995

By X. Baolin, R. Guru, M. Peiravi, M. K. Mohanty, Z. Qian, R. Ma, Z. Yude, L. A. Ackah

"Acid mine drainage (AMD) is produced when exposed pyrite (FeS2) reacts with air and water to form an acidic solution that usually contain contaminant levels of heavy metal ions. AMD can potentially contaminate surface water and soil if not treated. The primary objective of this study was to investigate the removal of dissolved aluminum, iron and zinc metal ions from natural AMD using water treatment residue (WTR), a low-cost adsorbent. WTR sorbent generated as waste material in drinking water treatment plants (WTP) was characterized and utilized for the sorption of Al, Fe and Zn in AMD collected from an abandoned coal mine site in southern Illinois that generates approximately 20 gallons per minute of AMD. Sorption experiments were performed using batch technique to obtain rate and equilibrium data. The effects of various parameters on sorption capacities of WTR were observed by varying contact time, pH of the AMD and WTR dosage. The adsorption studies showed rapid uptake in general for the first 80 minutes for Fe and Zn but much earlier for Zn. Further increase in contact time did not show significant change in equilibrium concentration indicating the onset of adsorption equilibrium. After the batch treatment of the AMD water with the WTR, the removal of Al, Fe and Zn were 99.8%, 99.85% and 95.5% respectively. The pH of AMD increased from 2.64 to a near neutral point of 6.74 after treatment. The laboratory results show that the low-cost WTR, which is an abundantly available industrial waste, has proven potential to significantly reduce the high metal ions in acid mine drainage. INTRODUCTION Mining activities provide the basic raw materials needed for infrastructure development and economic growth world-wide. However, it is well recognized that mining activities have been the cause of a variety of environmental pollutions, including AMD. Water seeping out of an old abandoned mine is generally characterized by low-pH with heavy loads of dissolved sulfates (SO4) and metal species such as Fe, Al and Zn among other dissolved elements categorized as toxic metals. The Bureau of Land Management’s Abandoned Mine Lands (AML) program reported the existence of about 46,000 abandoned mines in the United States. Several environmental problems have been reported to be associated with these mined out sites such as heavy metal poisoning, loss of vegetation, air pollution etc. (Boulanger & Gorman, 2004)."

Jan 1, 2017