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The primary use of coal in the US is for electric generation. The problems associated with the use of this vast amount of coal is the central theme of these sessions. The problems discussed include: production capacity, mining problems, coal cleaning, transportation, combustion, and various environmental problems, such as health effects of coal combustion, water and air pollution, and solid waste disposal.

Jan 1, 1979

Impala Platinum?s No.16 Shaft mine is currently under construction and is expected to reach full production of 256 500 tons per month by 2014. Mining will start at 1 260 m below surface with a maximum mining depth of 1 535 m where virgin rock temperatures of 56.6°C will be experienced. As a result of depth, high virgin rock temperature and narrow reef mining, an expected total of 31.5 MW[R] of air cooling capacity will be required to achieve acceptable underground conditions. This will be achieved by cooling mine intake air in a single dedicated air cooling installation located on surface. The compact installation includes air cooling spray chamber, refrigeration machines, condenser cooling towers, evaporator and condenser water reticulation as well as all electrical and control systems. Construction and commissioning of the first phase of this air cooling installation has recently been completed on a turn-key contract basis.

Jan 1, 2009

By Bruce Bryant

Silver ore was discovered at Aspen in 1879, but the district did not reach full production until 1888 after lawsuits were settled and railroads furnished less expensive transportation to the outside world. The boom years were 1888-92; production declined thereafter. From the middle 1920's until 1950, the Midnight mine in the Richmond Hill district furnished most of the output in the Aspen quadrangle. Since 1950, little mining has been done at Aspen. The metals produced were silver, lead and zinc. Native silver dissolved from the sulfide ores was redeposited by waters circulating as deep as 300 m below the land surface, resulting in great secondary enrichment of many of the deposits. Over 100 million ounces of silver were produced in the Aspen quadrangle. Low-grade lead-zinc deposits remain between the old workings locally, and data available suggest that primary ore below levels mined is also of low grade. The ore occurs in the Mississippian Leadville Limestone and the lower part of the Pennsylvanian Belden Formation in sites that were made favorable for deposition by a number of stratigraphic and structural factors.

Jan 1, 1982

By LaTasha R. Swanson, Jennica L. Bellanca

Proximity detection systems (PDSs) for mobile machines have the potential to decrease injuries and fatalities. Early adopters of the technology have identified some challenges, which present an opportunity to explore and improve the integration of mobile PDSs in underground coal mines. The current research study applied the task-technology fit framework to investigate the fit between mobile PDS technology and mining relative to health and safety, from the perspective of leaders at two coal mines. Quantitative results from the study show that mine leaders evaluated mobile PDS favorably for training and ease of use, system feedback, user authorization and experience, and less favorably for safety, compatibility, task completion, and reliability. Qualitative results reveal specific task, mine, and system characteristics that may have influenced leaders’ evaluations. The study includes considerations and suggestions for safe technology integration

By L. E. Eary

Many of the major international gold mining companies provide data on rates of greenhouse gas (GHG) emissions as part of their environmental reporting commitments. These data are evaluated by an index defined as the annual GHG emission rate in metric tons, divided by the annual amount of gold produced in grams, and referred to as GHGgold. This paper examines ranges of GHGgold values for a cross section of gold mines as a function of mining method (openpit, underground and combined operation) and ore-processing method (mill, heap leach and combined methods) for reported ranges of operational data, including annual total tons mined, ore processed and gold grade. The evaluation shows that ranges and distributions of rates of GHG emission are approximately similar across different mining methods and ore-processing methods. The data presented in this paper provide the context needed to make comparisons of GHG emissions reported in companies’ annual reports to the ranges reported for the overall gold mining industry.

Jan 1, 2009

The Yanacocha Project is the first foreign investment in Peruvian mining since Cuajone (1976). Three years after the project began, it has become the largest producer of gold from heap leach operations in the world and the top producer in Latin America. The success of Minera Yanacocha (MYSA) opens a new chapter in Peruvian mining with the exploitation of its widely spread gold deposits and has attracted the interest of foreign investors in Peru's ample mineral resources. Construction began on August 1, 1992 and after twelve months of arduous work, the first gold bar was poured on August 7, 1993 from ore from the Carachugo mine. In 1993, Minera Yanacocha produced 81,000 ounces of gold and 304,000 ounces in 1994 (40% above budget). Production is expected to exceed 500,000 ounces in 1995 with the start-up of operations in the Maqui Maqui mine. This paper presents a summary of MYSA's experiences during its first two years of operations in the areas of mining, ore processing, environmental protection, loss control and community assistance. The paper also shows that MYSA's successes are not only due to the richness of the deposit, but also to the combination of a number of factors basic to the project's success, such as: an economic policy favoring investment in Peru, the availability of highly qualified local personnel to facilitate the transfer of technology from the United States and the desire and determination of the partners to carry the project forward in an initial atmosphere of uncertainty and terrorism.

Jan 1, 1996

By James N. Orlich

Meridian Gold Company's Royal Mt. King mine (RMK), a subsidiary of FMC Gold Company, is located approximately 40 miles east of Stockton, California on the western edge of the historic mother lode belt. Gold ore at RMK is associated with a series of northwest trending fault zones hosted in either meta-volcanic or meta-sedimentary rock types commonly referred to as greenstone sulfide and carbonaceous phyllite. Mineralogy studies show gold in both ore types to occur primarily as electrum in the form of 1 -20 um inclusions in pyrite with varying amounts of free milling gold. In carbonaceous ores, gold was not found to be closely associated with carbon. At the start of the current mining operation, three major ore resources were identified. North Pit and Gold Knoll pits were the major greenstone reserves while Skyrocket Pit contained over 60% of the total reserves as carbonaceous ore. Since North Pit and Gold Knoll were to be the first areas mined, the mill began operation in February 1989 with a flowsheet designed for greenstone ores with a carbonaceous expansion anticipated after depletion of the greenstone reserves.

Jan 1, 1992

By T. L. Owen

Since 1993 Cyprus Amax has brought $2.5 billion dollars of greenfield and expansion projects into production, taking it from a mid-sized domestic minerals company into a major international minerals organization. The near simultaneous development of these multiple mineral projects in different locations around the world provided the opportunity for Cyprus Amax to develop a formal project management approach based, in large part, on an outsourcing philosophy. This formal project management system along with its outsourcing philosophy has served the growth agenda of Cyprus Amax extremely well. These preceding factors, coupled with the in-house retention of a core project group that fully understands the breadth of skills and abilities needed to undertake development of multiple large projects successfully, have been the cornerstone of Cyprus Amax’s project development success.

Jan 1, 2000

By Enrique Jelvez, Pierre Nancel-Penard

The traditional way of generating open-pit mine production schedules has several limitations. This work addresses the design and production-scheduling problem by considering minimum operational space requirements under a Direct Block Scheduling approach to generate extraction sequences that satisfy the operational space required. For this, traditional formulations were extended by including a new set of constraints that generate operating spaces for mining equipment to move and extract material. Then, a heuristic algorithm produces close to optimal practical pushbacks. This proposal was applied in a case study, and the results show its ability to generate practical production schedules without sacrificing expected return, obtaining differences in terms of Net Present Value (NPV) lower than 1% when compared to the traditional approach.

Jun 25, 2023

By L. P. Johnson

Longwall mining has gained acceptance as a safe method of maintaining coal production where conventional systems were unsuccessful or uneconomic due to bad roof conditions (Kuti8). One of the major problems confronting American operators involves the correct choice of equipment which should be selected to suit the local mining and geologic conditions for optimum productivity. To achieve this, factors such as rock strengths, local geology, panel geometry, and panel orientation must be examined to optimize production and minimize down time due to ground control problems. Little quantitative information is available in the literature regarding the effects of geologic conditions on American longwall operations, and past implementations of longwall systems appear to have been based largely on experience. When mining engineers are able to assess the geologic conditions both quantitatively and qualitatively, they can more fully optimize equipment selection and panel design.

Jan 1, 1977

By S. L. Manske

The Mesquite gold deposit is a recent discovery of Gold Fields Mining Corporation lying 65 kilo- meters northeast of El Centro in Imperial County, California (Figure 1). The deposit is located on the southwestern flank of the Chocolate Mountains and is a bulk-minable, low grade "disseminated" orebody. Although the host rocks of the deposit are part of a regional high-grade metamorphic terrane, abundant brittle fractures, brecciation, and open-space vein fillings indicate that Mesquite mineralization is epithermal. Faulting which postdates the hydrothermal activity has complicated the original geometry of the orebody. Alluvium effectively hides most surface expression of the mineralization, but open-pit mining is now revealing the details of Mesquite geology.

Jan 1, 1987

By J. M. Pachter

Property sales and acquisition are prominent features of today's coal industry. Before selling or buying a site, a company must know the property's economic net worth. Any evaluation of economic net worth would be inadequate if determinations of a property's environmental liabilities and costs were omitted. Short-term and long-term costs can result from liabilities related to reclamation, water treatment, subsidence, and hazardous waste disposal. A structured, interdisciplinary approach can aid in the delineation, summation, and scheduling of these costs and liabilities.

Jan 1, 1986

By Siddhartha Roy, Hemant Agrawal, Ram Madhab Bhattacharjee, Devi Prasad Mishra

Heat stress in underground coal mines is a major threat to the health and safety of the miners. Hence, managing heat and prediction of heat stress in advance is essential for maintaining a safe, healthy, and productive underground mine environment. In this study, an extensive ventilation survey has been carried out in three different deep and mechanized underground coal mines. The ventilation survey data are used to develop 3D simulation models with the VentSim™ software to predict the conditions that could cause heat stress in underground mine workings. The developed 3D models predicted well the wet-bulb globe temperature (WBGT), a recognized indicator of potential heat stress, with a coefficient of determination (R2) of 0.986, 0.994, and 0.993 for Mine-A, Mine-B, and Mine-C, respectively. Moreover, through 3D modelling, the applications of auxiliary ventilation and spot coolers to reduce the wet-bulb globe temperature (WBGT) for improving the underground workplace environment have been explored. The study demonstrated that auxiliary ventilation and spot coolers can help in significant reduction of heat stress conditions in an underground mine environment. By application of auxiliary ventilation, to increase air volumes, and spot coolers, the WBGT index in mining faces is reduced by 1.2–1.4 °C and 3.9–5.4 °C, respectively. Therefore, it is concluded that the spot coolers are more effective in reducing the heat stress conditions in hot and humid underground mine environments in comparison with auxiliary fan that is used to increase the air volume and velocity. This study opens up a new horizon of 3D simulations for heat stress management in underground mines. The outcome of this study will be useful for the researchers, mine operators, and environmentalists understanding the heat stress contributors and their control in underground mine environment.

May 10, 2023

By Shigeru Nishitake

The Earth Pressure Balanced (EPB) shields designed by Mitsubishi Heavy Industries, Ltd., are recently more enthusiastically accepted by tunnel boring specialists. This company having built 1,000 tunnel shields utilizes its vast experience to resolve the problem to excavate through big boulders scattered in rather soft alluvial soil. Several types of EPB shields which can cope with large size boulders are described. Such shields are equipped with both drag bits and rolling disc cutters on the cutterheads. Previously removal of boulders has presented safety problems for workers while in the muck chamber, or venturing in front of the shield. This report describes the problem and how the equipment was modified to deal with the problem.

Jan 1, 1987

By M. Tokoglu

Accurate estimation of resources is one of the major challenges in mineral project evaluation. Contemporary mineral resource estimation practice calls for contribution from several disciplines and execution of several interdependent tasks. 3D estimation domain modelling is obviously one of the most essential components of such a substantial process which forms the basis of this research. The study constitutes a comparative analysis of four major domain modelling techniques; (i) explicit modelling, (ii) implicit modelling, (iii) indicator kriging, and (iv) conditional simulation. It involves comparison of outcomes for alternative scenarios to assess the implications of the modelling decision on resource estimates of a polymetallic massive sulfide deposit located in western Turkey. Thus, identical grade estimation method and parameters are considered to identify the discrepancies arising only from the choice of the domain modelling approach and underlying assumptions. Economic implications are demonstrated in the form of range of outcomes for the extends of the ultimate pit, ore tonnages (min:37.0 Mt, max: 46.7Mt), waste tonnages (min:201.2 Mt, max: 251.2 Mt), stripping ratios (min:5.18, max: 5.71), and total pit values (min: $1.05B, max: $1.45B). Examination of solid models as well as cross-sections revealed that major discrepancies are observed beyond outlying drillholes. Therefore, it has been proposed that assumptions regarding extrapolation distance is the main source of mentioned dissimilarities. Key words: Domain modelling, explicit modelling, implicit modelling, indicator kriging, conditional simulation INTRODUCTION Resource estimation is apparently a challenging process calling for extensive expertise and input from several sources, each of which introducing its related uncertainties. In the last decades, substantial role of quantitative analysis of several forms of risk and uncertainty in evaluating projects’ upside potential and downside risks has been realized. Studies indicated that mining companies have been severely impacted because of not meeting project expectations. As noted by Vallee (2000) “… in the first year of operation after start-up, 60% of mines surveyed had an average rate of production less than 70% of designed capacity”. Several other studies on mining projects also revealed that uncertainties related with the resource model are one of the major contributors of mentioned shortfalls. In this perspective, quantification of uncertainties associated with each component of estimation process is critical. 3D estimation domain models capturing major mineralization controls are the fundamental components of contemporary mineral resource estimation. Domain models are key guiding tools for estimation and are products of a complex process involving many unknowns and assumptions. There exists a number of 3D modelling alternatives which are distinct with respect to complexity, time and effort involved. Acknowledging potential influences on downstream mining practices and relavent economic implications, risks and uncertainties associated with 3D domain modelling are critical yet poorly studied aspects.

Jan 1, 2019

By Qinghua Gu, BUQING XUE, XUEXIAN LI, JIANGSHAN SONG, Qian Wang

To solve the problem of time-consuming and low precision in updating the open-pit vehicle transportation network, a high precision road network model construction method for unmanned vehicles in open-pit mines is proposed. This method can be divided into two steps. In the first step, an improved deep learning image processing model named DeepLabv3 + C (DeepLabv3 + Concat) is presented. Then, the road information extracted by the DeepLabv3 + C network is used to construct a three-dimensional model of the open-pit mine road network. In the second step, aiming at the time-consuming problem of unmanned vehicle meeting in open-pit mines, a vehicle meeting strategy was proposed. This strategy is used to guide the navigation of unmanned vehicles in open-pit mines. Besides, the DeepLabv3 + C network is verified by comparing the mIOU (means Intersection Over Union), accuracy, and continuity of road image extraction with the mainstream networks. The road network model constructed in the first step is quantitatively analyzed, and its performance is compared with GPS trajectory clustering methods. At the end of the paper, vehicle running simulation is carried out on the road network model by using Unity (a 3D visualization simulation software). The results show that the road network model constructed by this method can meet the navigation requirements of unmanned vehicles in open-pit mines, and the feasibility of the vehicle meeting strategy is proved.

Jan 11, 2022

By J. A. Delgadillo

Computer simulation and mineral modeling was applied to the optimization of a grinding circuit in a plant processing 256 t/h magnetite. These tools were used to develop a grinding and classification configuration to decrease the grade of silica in the magnetite concentrate, which is produced by the plant. Empirical grinding and classification models were finely tuned using plant experimental data. The JKSimMetTM 5.0 software was used to simulate the grinding and classification units. By applying changes in the original circuit, a throughput increment of 100% was achieved with an important reduction in the energy consumption. The silica content in the magnetite concentrate can be decreased by regrinding the coarse fraction of fine screens into a separate ultrafine grinding unit instead of returning this flow to the ball grinding mills.

Jan 1, 2008

By S. M. Flaherty, R. E. Scheffel, A. Guzman

Geochemical conditions within a leaching operation are heterogeneous. This variability arises mainly from hydrological controls imparted by physical characteristics of the ore and by heterogeneous metallurgical properties at the rock-fragment and industrial heap scale. The resulting chemical conditions are responsible for stratified mineral recovery, non-uniform extraction and prolonged leach cycles. This paper presents field data from a sulfide-leaching operation which clearly demonstrate the impact of chemical heterogeneity on metal recovery and the potential use of modern measuring techniques to facilitate operational monitoring and decision making for optimization of leaching operations.

Jan 1, 2006

By E. Ashworth

A thermistor probe has been developed to measure in situ temperature profiles underground. A full description of the probe is given. Data collected from the probe has been used to compare the actual profiles with those predicted from a finite element analysis using laboratory measured thermal properties of the different rock types. This comparison indicates the applicability of laboratory measured parameters in modeling the real conditions. Factors such as applied pressure, moisture content and anisotropy on laboratory measurements is discussed.

Jan 1, 1983

By Shailendra Chawla, Ashok Jaiswal, B. K. Shrivastva

The study aims to evaluate the pillar behavior during the depillaring operation by continuous miner (CM) technology. A panel with five headings developed as per the coal mine regulation of Indian coal mines [2] has been selected for the study. The depillaring operation has been carried out using CM technology after widening and heightening the original entries. An extensive field investigation has been carried out throughout the depillaring operation to access the mining conditions. Depillaring operation has been performed smoothly up to the middle of the panel (fourth row out of eight rows of four pillars each). Advanced blinking of the auto warning tell-tale (AWTT ) has also been observed on some of the instruments during the splitting of pillar no. 18. The panel shows extremely difficult mining conditions at this stage. The case has been numerically simulated using three-dimensional numerical techniques. The simulation result has indicated the high stress and yield condition on the working and the barrier pillar (surrounding goaf from both sides) after the extraction of pillar no. 18. The analysis has also indicated the marginal stability of the 2nd barrier pillar (namely “pillar B”). The failure of the barrier pillar could be the responsible for global instability of the panel as observed in the field. Understanding the importance of the barrier pillars, panel design has been modified by incorporating an additional row of barrier pillars. The stability of the modified panel has been evaluated. Both working and barrier pillars have been observed stable in the modified panel. This could be an alternative layout considering safety at the working face.

May 8, 2022