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By R. E. Brewer

Phelps Dodge Mining Company (Phelps Dodge) is operating a pressure leach vessel (PLV) for copper concentrates at the Bagdad Mine facility in Arizona. This single PLV unit was engineered and constructed based on continuous laboratory testing, reaction chemistry and kinetics, and available pressure vessel technology. The challenge of designing for optimum process retention time, agitation, oxygen mass transfer, temperature and pressure will be reviewed in this paper. The PLV interior lining, agitation equipment and compartment configuration chosen for the PLV will also be reviewed.

Jan 1, 2004

By R. J. McGregor, Deepak Malhotra

Engineers frequently encounter situations where decisions that are counterintuitive to the logically trained engineering mind are made because of other influences, whether they be financial, social, cultural, or environmental. Such influences can overrule the "logical" decision-making process. The aim of this book is to explore some of the nontechnical issues, which most engineers don't learn about in school, that can have a major impact in the mining industry. This chapter gives a brief overview of this volume and introduces the topics that will be addressed.

Jan 1, 2001

By Theodore M. Olson

The Washington State Highway Department consists of seven geographic dis¬tricts. District offices are located in Seattle, Wenatchee, Olympia, Vancouver, Yakima, Spokane and Bellevue. District is covered from the Spokane office, and is responsible for the six counties in the northeast corner of the state (Fig.l). It is bordered on the north by the International Boundary, on the south by the Snake River, on the east by the Washington - Idaho border, and on the west by a north-south line thru Lake Roosevelt. The landslides to be discussed in this paper are at Colfax, Washington, which is located in the southeast corner of the district. The town of Colfax is situated in a narrow valley eroded into the Tertiary volcanic basalts by the Delouse River. The valley walls are steep and generally colluvium mantled. State Highway 1°c, from Spokane to Colfax, descends into the valley from just north of Colfax on a bench cut into the valley wall. The highway department designed a widening project to increase the misting two lane roadway to three lanes, thus providing a passing lane for uphill traffic. The third lane was constructed as a cut section for the entire length. Construction excavation was begun at the top of the hill in silts of eolian origin. Proceeding downhill, excavation encountered three individual basalt flows with two zones of palagonite tuff separating them. The upper palagonite zone was dry, and excavation proceeded across this zone with no mishaps. The lower palagonite zone carried considerable groundwater. As excavation crossed the lower zone landsliding became contemporaneous with excavation, due to removal of toe of slope and saturated conditions. Remedial measures for landsliding consisted of designing shot rock buttresses across the palagonite zone and also the installation of horizontal drains to reduce hydrostatic pressure.

Jan 1, 1971

By Shail J. Butani

This paper analyzes the 1982 coal mine accident data collected by the Mine Safety and Health Administration (MSHA) for key equipment types, by mine type, and by geographic region. The differences in hazards associated with the various equipment types are studied both in absolute (i.e., total number of incidences) and relative (i.e., incidence rate or the number of incidences per 200,000 employee or exposure hours) terms. The paper compares and contrasts the total number of incidents as well as incidence rates classified by several types of severity measures such as lost workdays cases, mean number of lost workdays per lost workdays case, fatal cases, non- fatal cases without lost workdays, total number of cases, and total number of lost workdays This statistical analysis shows that significant differences in hazards exist not only due to equipment type but also due to mine type and geographic region.

Jan 1, 1986

By J. P. Matoney

The operation of a modern coal preparation plant, particularly in western Canada, is a very complex task. Most western Canadian operations are processing two or more, sometimes up to ten, different seams through the same plant. This requires a sophisticated multi-circuit plant that needs close operational control. Add the soft nature and large amounts of natural fines of western Canadian coal and you have a formidable cleaning task. To assist in the operation, programmable controllers and sophisticated control concepts are being more widely used. Two of the newest coal preparation plants in Canada have been designed by Raymond Kaiser Engineers Inc. and its Canadian subsidiary, Phillips Barratt Kaiser Engineering, Ltd. The use of programmable controllers and control systems will be illustrated by showing their application in a "typical" western Canadian coal plant. This example will cover flowsheet design, control concept systems application, and possible future uses.

Jan 1, 1983

By H. Cetin

The availability of coal resources of selected 7.5-minute quadrangles of southwest Indiana was examined in this study. Resources were defined as original coal in place, remaining after mining, and currently available considering land-use and technological restrictions. The amount of coal mined from each study area varies depending on the mining practices of the companies operating within the area. Of the three quadrangle investigations, the available resources range from 50 percent to 79 percent of the original resources. Most of the coal resources under deep-minable category were not available because of technologic restrictions, such as insufficient coal thickness.

Jan 1, 1996

Despite two large projects represented in the keynote docket, the mood of the 2011 SME Arizona Conference was summed up best by Ferol Baker, general manager of New Mexico Copper Corp. (a wholly owned subsidiary of Themac Resources Group), ?In the past, it seemed like you couldn?t go to a conference like this without hearing about one big new greenfield project after another. Now what you see is companies doing internal expansion or small-scale brownfield development.? Overall, the tone of this year?s meeting, held at the J.W. Marriott Resort at Starr Pass in Tucson, AZ, was upbeat, yet practical. From the keynote and luncheon addresses to the six panels of sessions, the projects described were positive about the future, yet focused on the details required to make those projects come to fruition.

Jan 1, 2012

By E. Wm. Heinrich

Glass sands fall into that extremely select category of mineral deposits that requires a fantastic degree of natural concentration (95% +) of a single component before they can even be considered as ores suitable for further refinement. The combination of geological factors that has produced such an environment of "mineralogical single-mindedness" has appeared only rarely. Factors that require consideration in the economic evaluation of a potential glass-sand deposit can be grouped into three categories: 1) geological (e.g., size, shape, structure); 2) petrographic (e.g., grain size, accessory minerals, nature of iron contaminants); 3) geographic - political (e.g., proximity to consumer, size of market, zoning restrictions). Of particular con ern is the nature of the iron contamination. Iron-bearing species appear as 1) accessory mineral grains, either detrital or authigenic, 2) cements, 3) grain coatings, and 4) quartz-grain inclusions. Selection of the cheapest form of beneficiation requires precise information on the mineralogy of the iron species and their detailed petrography. Because of the antipathetic relationships, in many parts of the United States and Canada between the geographical locations of glass plants and the geological distribution of glass sands, the selection of ac suitable source for a particular glass plant may be dichotomous. One may seek either an exceedingly pure "classic" type glass sand that is relatively distant and whose cost includes a major transportation charge or a relatively proximate and somewhat "impure" source whose cost includes a substantial fee for beneficiation.

Jan 1, 1974

By Om P. Garg

The purpose of this paper is: 1) To summarize the capabilities and some of the limitations of the existing mine planning software. 2) To provide some guidelines for acquiring the software. 3) To identify problems and challenges in terms of how to justify increased use of computers (particularly the 32-bit microprocessor based super micro computers), for various activities related to a mining operation No attempt has been made to review the contents of available software packages in detail. Also the scope of this paper is limited to mine planning related computer applications. Applications related to accounting, inventory control, preventive maintenance, equipment scheduling, etc. have not been covered.

Jan 1, 1983

By K. W. Morris

Of the fossil fuels used for power generation coal is by far the most variable and complex in its properties. A thorough review of the characteristics of the coal to be fired is essential before boiler design can begin. Major parameters such as heating value, moisture content and ash properties will determine not only the boiler size and configuration, but also the performance of the unit with respect to the thermal efficiency, particulate and gaseous emissions, and unit availability and reliability. An example of a review completed on a large low-rank coal deposit for a power plant will be described.

Jan 1, 1983

By J. D. Grenia

The Buick Mine is a joint venture of American Metals Climax, Inc., and Homestake Mining Company located 120 miles by road southwest of St. Louis, near the village of Boss, in the 'New Missouri Lead Belt' (See Figure 1). Since start-up in 1969, over four million tons of lead-zinc ore have been mined and milled at Buick. Situated about 1,100 feet below the surface at an elevation 270 feet above sea level, the flat lying sinuous ore bodies are up to 250 feet wide, 85 feet high and several thousand feet long. Mineralization is galena, sphalerite and chalcopyrite in dolomite, Access to the mine is through two 18'Ø concrete lined vertical shafts - one for servicing and the other for hoisting ore (See Figure 2). The mine is being worked by a modified room and pillar method using both rubber tired equipment and a sub-level rail haulage. Ore is broken from first pass headings, back and bench faces and transported by load-haul-dump units to ore passes located on 900 foot centers. The ore is pulled from chutes on the sublevel 90 feet below into 15 ton bottom dump cars and delivered in 10 car lots by a 15 ton diesel locomotive to a 42" gyratory crusher (See Figure 3). A recent innovation has been the introduction of two 50 ton trucks with plans to haul up to 60% of the ore on the mining level to an ore pass feeding directly to the primary crusher (See Figure 4). Ventilation raises up to 16'Ø, which were originally planned for 900 foot centers, are now driven on 450 foot centers.

Jan 1, 1973

By A. Mei, F. Amadini, F. Cernera, D. Baliani, A. Flor, M. La Morgia, F. Sassi

The risk of TBM jamming because of squeezing rock mass or excessive caving (instability of the cavity) conditions is always a focal point while boring long and deep tunnels with shielded TBMs. Mechanized excavation provides a large amount of real-time data, for each machine’s parameters. Several analyses have been executed to assess the correlations between different sets of TBM parameters for the exploratory tunnel. Instead of analyzing the full dataset, a different approach is proposed, with data processed sequentially to simulate the real excavation situation. The probability distributions are recalculated together with their statistical parameters while advancing. This approach is extended also to the training of a Machine Learning model able to foresee the behavior at future rings based on past rings (using a Recurrent Neural Network). The predictions show a promising first step toward creating practical tools that can assist contractors and designers to correlate and predict TBM excavation data. These tools will assist to predict and quantify high risk situations that could arise during excavation.

Jun 13, 2023

By W. R. Boehme

The test work was done in two parts. In Part I, five 6 x 16 mesh activated coconut shell carbon samples made by four different manufacturers were evaluated as to their gold loading rate and total gold loading. The five carbon samples tested are not identified by manufacturer and are simply designated as Types A through E. Then from the carbons tested, a suitable highly active carbon was selected for subsequent studies on impurity effects upon loading, Part II. Test Procedures The procedures and tests descriptions are given for the ultimate gold carbon loading tests and the dynamic gold carbon loading tests.

Jan 1, 1983

By Smart Chika Obiora, Anthony Chukwu

Lead and zinc have been mined for over 90 years in parts of the Lower Benue rift in southeastern Nigeria. However, there has been little interest in the sustainability of the environment and the inhabitants of the host communities. Adverse effects include soil and food crop contamination, lack of education, poor healthcare, unemployment, and no access to potable water. This work suggests practicable mitigation strategies to ameliorate these negative effects and promote environmental sustainability.

Jul 1, 2023

By V. O. Tenorio, K. P. Hague

Mines are constantly trying to improve production processes by optimizing work cycles, reducing operational delays, minimizing costs, controlling equipment utilization, and preventing occupational hazards. Currently, advances in digital mining technologies within the concepts of 5G and Industrial Touch Internet are allowing better control and monitoring of underground mining equipment, with centralized control systems that unify data analysis for proper decision making. A wireless 5G-based platform for controlling and monitoring systems for underground mine operations can be designed over a comprehensive layout in where bandwidth selection, sensor location, Wi-Fi repeaters and power distribution are put together to build a successful supervisory system. In order to confirm the validation of these concepts, a case study is proposed for a medium-sized underground mine with a multi-level network which includes tablets managed by production supervisors, along with other data collection devices installed in semi-autonomous mining equipment, collecting, and distributing data in near-real time, with interconnection to support and services areas on the surface.

Mar 2, 2022

The choice between EPB - and Slurry Shields is influenced by the following factors: grain size distribution, cohesiveness, occurence of boulders, occurence of gas, feasibility of soil separation and muck disposal, and settlement properties of the soil. The simple equation cohesive soils = EPB Shields and non cohesive soils = Slurry Shield is very often superimposed by other facts. For example, the occurence of a large amount of boulders in weak cohesive soils, where the application of roller discs is not recommendable, may lead to the use of a Slurry Shield with a rock crusher, thus accepting the disadvantage of a sophisticated separation plant; whereas the occurence of contaminated groundwater or gas may exclude the use of a Slurry Shield. In the following examples the choice of a Slurry Shield or EPBS will be explained and justified with regard of the above factors.

Jan 1, 1995

By William E. Wallace, Larry Grayson, Thomas Simonyi, Joel C. Harrison

Application of an SEM-based methodology suggests a reason for past contradictory results on the relationship between quartz and coal workers' pneumoconiosis (CWP). Results indicate that coal seams with the same bulk analysis of quartz have different amounts of surface-available quartz. Our research shows that the amounts of pure and surface-available quartz in a respirable dust vary directly with the rank of a coal seam, except in the case where rock materials are mined. The estimated amount of surface- available quartz therefore provides a measure of the quartz-related fibrogenic potential of a respirable dust.

Jan 1, 1992

By L. W. Ashton

Geochemical exploration guidelines were developed from a study of 460 rock chip samples collected at nine disseminated gold deposits in Nevada. Obtaining high grade Au samples is difficult because gold content is extremely variable, even over 8 m (25 ft) distances. For reconnaissance sampling, pathfinder elements are reliable indicators with threshold values of 100 ppm As, 1 ppm Hg, and 50 ppm Sb. Arsenic is the most reliable of the three elements, being significantly enriched in all deposits. If the pathfinder threshold levels are reached with low Au content, more samples should be collected. Successful disseminated gold exploration requires large numbers of samples.

Jan 1, 1990

By W. M. Ma, Daniel W. H. Su, K. Centofanti, Yi Luo, W. L. Zhong, Syd S. Peng

8.1 INTRODUCTION Under room and pillar mining if the extraction ratio is low, (i.e., < 50%) a pillar can support the overburden without collapse and there will be no surface subsidence whatsoever. In other words, if the pillar sizes are properly determined to support the overburden weight, the roof strata cannot cave and there will be no surface subsidence, provided the entry width is small and properly reinforced so that a continuous roof fall leading to piping or the total collapse of the roof does not occur. Under the prevailing mining conditions in the US if only development mining is em¬ployed in room and pillar mining (i.e., no pillar extraction), the extraction ratio is usually less than 50% and generally no surface subsidence will occur. If pillar mining is employed, surface subsidence may occur, depending on the extraction ratio and the size of the remnant pillars (or stumps) left in the gob. The higher the extraction ratio, the smaller the stump pillars left behind in the gob. As the size of the stump pillars becomes smaller, the possibility of their support¬ing the roof without collapse is smaller. If all stumps are crushed completely, the roof will collapse and surface subsidence will occur. Again, whether surface subsidence occurs, it depends on whether the remaining stumps can support the overburden or not. Therefore, since the weight of the overburden which the stump pillars have to support is proportional to the mining depth, a fixed¬size stump pillar can support the overburden at a shallow depth, but will collapse under greater depths. In this context extraction ratio is not the only parameter for determining whether surface subsidence will occur. Furthermore, during pillar mining a pillar can be cut away in many ways to finally reach the same extraction ratio. Therefore, the safest way to determine whether or not sur¬face subsidence will occur in room and pillar mining is to compare the strength of all stump pillars in the panel of interest with the weight of the overburden that the pillars have to support. If they are too small to support the overburden, surface subsidence will occur. Under normal mining practices the characteristics of surface subsidence profiles vary with methods of mining. In the US there are two types of coal mining methods, i.e., longwall and room and pillar mining. Longwall mining is indisputably a total extraction method, but different percentages of coal recovery are achieved in room and pillar mining. Recovery is much higher for sections with pillar extraction than those without pillar extraction. For those without pillar extraction, coal recovery increases with increasing entry width or decreasing pillar size. For those with pillar extrac¬tion, the total coal recovery depends on the amount of coal ex¬tracted from each pillar which is in turn dependent on the roof conditions and methods of pillar extraction. Bauer and Hunt (1981) analyzed the characteristics of the subsidence profiles due to the three types of mining methods in Illinois. Fig. 8.1 shows the range of locations associated with the following profile features: profile edge, maximum tensile curvature, maximum slope, maxi¬mum compressive curvature, and maximum subsidence. The scat¬ter of the data increases with decreasing percentages of extraction. The profile is much sharper for longwall mining and becomes milder as percentage of extraction decreases; for longwall mining the profile edge is always beyond the opening, while in room and pillar mining it may fall within. The location of maximum tensile strain moves outward, while that of the maximum compressive strain moves inward as the percentage of extraction decreases and the maximum subsidence decreases with decreasing extraction ra¬tio. The general concepts discussed in this chapter may not apply to the entry development sections between two longwall panels where roof caving in both panels are very severe and overlap each other. Consequently, it must be treated differently. 8.2 CASE STUDIES Kohli et al. (1982) described several case studies on surface subsidence due to room and pillar mining with pillar extraction. In one case, the seam was 6 ft thick and ranged from 650 to 800 ft deep. The panel was 720 ft wide (Fig. 8.2) and was developed with seven entries. Each entry was 18 ft wide and the pillars were driven at 88 ft center-to-center between entries and crosscuts. Dur¬ing retreating, two additional pillars (pillars J and K) were devel¬oped, two blocks ahead of the pillar line, to take the barrier pillar, 160 ft wide, between panel No. I and No. 2. Pillar extraction began by taking a central slice across the whole panel, beginning from pillar 0 through J. After that, each pillar was sliced by 6 wing-slices, 3 on each side, leaving 4 stumps, 2 on each side. One of each pair was triangular shaped approximately 6 ft wide by 26 ft long. The other was trapezoidal, 26 ft long by 16 ft and 10 ft wide at the upper and lower bases, respectively. This resulted in a total extraction ratio of 85% within the panel. Obviously the stump pillars were not large enough to support the overburden and col¬lapsed completely. The final subsidence profiles were rather smooth, just like those under total extraction (Fig. 8.3). The max¬imum subsidence on Lines A and B was about 3 ft for an average mining height of 6 ft, but the locations of the maximum subsidence were skewed toward panel No. 1. Along Line D, the central por¬tion was flat-bottomed, but the maximum subsidence was only 2 ft, mainly because Line D was only two blocks from the right-side edge. Notice in every profile there was heaving of as much as 0.3 ft, beyond the edges above the solid coal. In another case (Fig. 8.4), the seam was 6 ft thick under 650 to 850 ft cover. Three panels, 710, 400, and 350 ft wide, respec¬tively, were extracted side by side. The entries were 18 ft wide and the pillars at 88 ft center-to-center between entries and crosscuts. Pillar extraction was practiced the same way as described previ¬ously. According to the mine maps, there was no barrier pillar left between the adjacent panels. Thus after extraction the three panels formed a common gob of more than 1460 ft wide. This was re¬flected in the development of the subsidence profile along the county road. After Panel No. I was mined, the maximum subsi¬dence of 1.2 ft occurred at Monument No. 1. This was increased to 1.6 ft after the extraction of Panel No. 2 and went to a further 1.8 ft after the extraction of Panel No. 3. The final maximum subsidence of 4.3 ft occurred at Monuments No. 6 through No. 8, while the remaining portion of the county road showed rebound. However it must be noted that the subsidence profiles were rather bumpy and fluctuated, perhaps an indication of the irregular stump pillars that were left and crushed at various time after mining. Moebs (1982) surveyed the subsidence profiles of four room

Jan 1, 1992

By Mohammad Ranjbar, Zahra Manafi, FAZAELIPOOR MOHAMMAD HASSAN, HAMGHAVANDI MOHAMMAD RANJBAR, Mahin Schaffie

Bioleaching has an increasingly important place among available mining technologies as biological processes have emerged as alternatives for metal recovery, especially for metals like gold and copper. An important disadvantage of bioleaching is the slow reaction rates, with microbial attack times often lasting weeks. Therefore, applicable research is required to improve these rates. From previous research, copper bioleaching has been divided into two specific regimes: (1) surface reaction controlling step and (2) mix of surface reaction and diffusion controlling steps. The presented model, which includes the effects of both these regimes, predicted the results of copper bioleaching recovery with good accuracy.