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By D. Weston

During recent years there has been a great deal of confusion in the North American mining industry with the introduction of new comminution terminology and claims (without substantiative evidence), for various types of equipment in this field. The authors will attempt to clarify the terminology used, and where possible, give illustrations of plant practice with actual operational and pilot plant data. This is considered necessary in order to obtain a clear picture of the comparison of such equipment to the revolutionary change that the Aerofall Mill has brought to the mining industry.

Jan 1, 1964

By S. Rideout

The United States Department of the Interior's Office of Surface Mining (OSM) is responsible for regulating active coal mining and reclaiming abandoned coal mines in the United States. In working with the State government agencies that implement these programs, OSM is building a new approach that moves away from traditional "command and control" regulation and towards an approach that focuses on providing long-term environmental and economic sustainability on lands disturbed by coal mining. This initiative called "Reclaim the Future!" looks to enhance opportunities for economic development, wildlife preservation and enhancement, reforestation, and other beneficial and productive uses of lands disturbed by coal mining. The initiative is also focused on ensuring that the landowners and the local public have significant involvement in determining how best to reclaim mine sites and what post-mining land uses are most appropriate for each individual abandoned mine reclamation project or active mine reclamation. Through the use of the best scientific input in an open, participatory process, OSM hopes to further sustainable development principles for coal mining within the framework of existing United States law.

Jan 1, 2007

By T. Weatherwax, A. Rai, J. Poor

"This paper provides an overview of the current use of auxiliary ventilation products and the challenges with limited air quantity in dead-end entry or working faces. The PVC’s low frictional factor, low physical constraint and minimum leakage properties were ideal to develop as ventilation duct in conjunction with the concept of ""Made in the US and Used in the US"". The PVC duct supports the operational and total cost of ownership with on-going success. This paper will discuss the continuous improvement made in ventilation ancillary products for optimum results. The paper will also cover mine site usage of second generation PVC vent duct underground and the results from the operational and technical side making a difference in health and safety and overall auxiliary ventilation. INTRODUCTION The Barrick Turquoise Ridge Inc. (TR) is located in northern central Nevada, and is situated within the Basin and Range province, near the northeast end of the Osgood Mountains (see Figure 1). The TRJV mine consists of typical Carlin type- gold mineralization characterized by low strength rock of altered limestone, siltstones, and mudstones. The weak nature of the ground facilitates the need for underhand cut and fills mining methods.Mining Method; Underhand cut and fill: The mine uses underhand cut and fill method which has 12’x12’ and or 14’x14’ top cuts with several different size undercuts. The ore body is accessed off of a secondary tertiary heading, utilizing a heading with a cross section of 14W x 14H or 15W x 15H configuration. In the wider and more massive zones, two headings in a production panel may be worked at any one time. Drift round lengths are determined by the ground conditions and drift dimension. An example of a typical topcut and associated undercut layout is shown in Figure 2."

Jan 1, 2016

By Peter Cammack

Where raw coal from a mine is treated in dense medium separators ash in the washed product is generally very consistent, provided control of the medium suspension is maintained at a given specific gravity. When, however, the washing process is a Baum jig or other similar apparatus, making a separation at rather arbitrary gravities, the control of the product ash is less accurate, particularly in those cases where the design capacity of the washbox is exceeded by the load of high ash fines. In either of these cases an instantaneous measurement of ash while not essential would be desirable, to check the quality of the washed product and provide operator or management with instantaneous warning of changes in ash. Nearly 60% of all British coal mined goes for electricity generation, to burn at 17% ash, and since the overall average ash content of raw coal as mined is about 30% and varies within a range of 18 ? 40%, incombustible material has to be removed. The ash specification could be met either by total washing, or by washing part and blending the clean coal produced with the remaining untreated coal. Some plants use a straight tonnage split, but generally speaking in Britain it has been found more economical to screen and wash the oversize only. In either case for effective quality control in blending an instantaneous determination of the ash content of the product as it is made has been found essential, since standard ash determination by pyrolysis methods is lengthy and provides information too late to be used in the control of plants blending at the rate of 1000 ton/h.

Jan 1, 1976

By T. Klemetti, W. H. Su, M. A. Van Dyke

Entry stability in coal mines is dependent on geologic conditions and engineering controls. Most engineering controls in ground control are predictable and standardized for typical geologic conditions. However, geologic anomalies may exist that are difficult to detect with traditional core hole drilling. Borescopes offer a cost-efficient way to gather more geologic data between core holes. Additional data obtained from borescope results provide a clearer picture to enhance detection of hazardous conditions due to geologic anomalies. The equipment, methods, and analysis of borescope results provide geomechanical engineers with a clear understanding of strata behavior and the best information to implement roof control plans and supplemental support to enhance miner safety and health. INTRODUCTION Borescope technology has changed very little since its inception. However, the idea to use borescopes to examine roof strata started with the U.S. Bureau of Mines in 1979 with the production of a fiber-optic borescope (FitzSimmons, et al., 1979). The first documented use of a borescope in the coal mining industry began during the 1980s in Australia by researcher John Shepherd. Shepherd’s idea was to use a borescope to collect a series of data points from the roof lithology and compose a geologic cross section. The cross section was then used to identify key features that suggested the beginnings of roof failure. The features Shepherd identified were bedding plane separations in the roof and low angle, extension, and tensile failures. Shepherd also suggested that the borescope findings could be used for geologic mapping for lithological variation, fracture distribution, and determining if supplemental roof support was needed (Shepherd, et al., 1986). In the United States the first publication about borescope usage for coal mine stability assessment was by Su and associates in 1999, who specifically related the combination of using borescope, geophysical, and corehole data to produce geologic hazard maps (Su et al., 1999). This work directly linked the usage of a borescope with the design of supplemental roof support. The use of borescopes in mining was adopted industry wide by the 2000s. Operator case studies were being published using borescopes to aid in supplemental support recommendations and hazard mapping. An Australian study published in 2007 based the optimization of secondary support after each longwall pass on the results of borescope data. The study stated that the borescope was an invaluable tool for understanding roof behavior (Black, et al., 2007). In 2009, a publication by the National Institute for Occupational Safety and Health (NIOSH) took the concept of borescoping one step further. The work centered around creating a roof quality index (RQI) for limestone mines based on borescope data. The RQI attempted to assign a ranking to establish the nature of the roof and its stability (Ellenberger 2009). In theory, this would have been a very useful tool, but the RQI system has not been widely adopted in the industry.

Jan 1, 2019

By Stanley M. Jarrett

Gentlemen, I am pleased to address this gathering of engineers and operation managers representing a large and important segment of the metal and nonmetallic mining industry. Since you know from the printed program that the theme of my paper is the furthering of safety in open pit mines, perhaps you will have guessed that I will also comment upon the image created in the public mind by the industry's safety record and the potential consequences thereof in national health and safety legislation. Operators of surface mines have some cause to congratulate themselves on the basis of figures issued by the national safety council which show that lost-time accidents per-million-man-hours in surface mining (11.18), is lower than that of all other mining. Moreover, the accident frequency in surface mining is only slightly above the median accident rate for all American industry (8.87). That is a good record.

Jan 1, 1972

By Walter E. Dean

Deep-sea manganese nodules are considered to be potential ores of manganese, nickel, cobalt, and copper. Considerable time, effort, and funds have been applied to the study of Se distribution of nodules on the sea floor and the location of economically important areas, but little effort has been spent in understanding the origin of nodules. Most theories that have been proposed to explain the origin of manganese nodules have been based on inorganic physicochemical processes. It is not by coincidence, however, that the area considered to be most economically feasible is in the zone of high biological productivity in the eastern equatorial Pacific Ocean and underlain by siliceous biogenic sediment. The genesis of manganese nodules and the concentration of many trace elements are intimately associated with biological processes.

Jan 1, 1982

By N. L. Bingham

The mining industry's image is molded by what the general public knows, or thinks they know about mining. As we prepared for the production of Caterpillar's educational film, Common Ground, we first had to find out exactly what the public perceptions about mining were. Before we could educate people about mining, we had to find out what they already thought. As we broke down those perceptions, we were able to narrow our focus to relevant, realistic approaches for the film. We found out what people didn't know about mining. And most importantly, we singled out the facts they should know... facts that could create more favorable attitudes. This research was instrumental in our final direction for the Common Ground project.

Jan 1, 1994

By g. Caproni

The main constituent of the feed to the "Sulphide Section" (31 t/h), in the F. Sartori Plant (6000 tid) of the Miniere di Mon)eponi(Sardinia), is the ore of the Campo Pisano -Funtanaperda Mine (1 ? Difficulties have always been experienced in the treatment of this ore, owing to the extramely fine Pyrite-Sphalerite intergrowth and to the high Pyrite and soluble salts contents. The first mentioned difficulty was overcome with a rather complex flowsheet (see fig.1A and lB)(2); the others with a reagent combination that required a pH of 11 in a pulp loaded with soluble salts. This meant high consumption of alkalizer, and also of the other reagents; furthermore the alkalizer had to be mainly NaOH with only minor amounts of lime, because the latter tended to depress not only the pyrite but also the middlings, which were supposed to float. With dialchylditiophosphate alone as a collector, a lower pH could have been used, but a certain amount of amylxanthate was indispensable to promote flotation of the middlings. On the other hand, a bulk-flotation of sphalerite and pyrite at low pH could not be very advantageous on account of the high pyrite content in the feed(3).

Jan 1, 1971

The mining industry is an important economical factor in Vietnam. Mining is presently being conducted at about 60 locations and at over 1000 mines. Petroleum extraction and coal mining are the most important parts of industry though metals such as zinc, tin, chromites, iron are also extracted. Last year the sector produced 20 million tons of crude oil, 26 million tons of coal and 500,000 tons of apatite. In particular, Vietnam is one of the world?s largest producers of anthracite, and it is one of the top producers of ilmenite and zircon in the Asia-Pacific region. The government intends to increase the mining production on all levels, however, at present one can observe adverse impacts of the mining activities on the natural environment such as insufficient waste dump rehabilitation, occurrence of acid mine drainage, mining subsidence and emissions as well as lack of appropriate water treatment facilities. This paper describes the current mining situation, future perspectives, the major environmental challenges of the country and approaches to solve these problems. Particular emphasis will be given to the research project ?RAME ? Research Association on Mining and Environment in Vietnam?, a venture carried out by universities, research centres and industry. This project is worked out in collaboration with the national Vietnamese coal and industrial minerals company VINACOMIN.

Jan 1, 2006

By Wang Xuewen, Bao Qingbao, Xie Jiacheng, Yan Zewen

This study puts forward a virtual memory cutting method based on the prediction of AFC shape. The integrated key technologies include the generation of virtual teaching cutting curve, the height adjustment strategy of front and rear drum, cutting height adjustment strategy, the reciprocating cycle of cutting technology and so on. Through the two algorithms, SVM and ELM, the form of the next working cycle can be obtained by rolling prediction using the form information of AFC in the first several circulations. Based on the obtained dynamic fluctuation of the form in the vertical and horizontal working faces, the position and cutting information of the shearer during its operation can be controlled and predicted in advance, the memory cutting template can be adjusted and modified in time. Employing this method, the more stable, accurate and timely memory cutting of the shearer under the uneven coal seam could be realized.

Aug 16, 2021

By W. J. Guay

Carbonaceous gold ores containing gold dispersed in sulfides are refractory to cyanidation because: ( 1) the carbonaceous materials adsorb gold during cyanidation; (2) a portion of the gold is so finely dispersed in the sulfide mineral lattice as to preclude contact with cyanide solution; and (3) a portion of the gold is chemically combined with carbonaceous material. Techniques which have been used to treat these ores are: (1) roasting or chemical oxidation to decompose sulfides and carbonaceous materials; (2) flotation to reject carbon; (3) the use of kerosene or other reagents to passivate the adsorptive carbon compounds; (4) carbon or resin in pulp; (5) flotation of a bulk concentrate which is treated by one of the above methods; and (6) the use of chelating agents which have a stronger affinity for gold than the activated carbon in the ore.

Jan 1, 1981

By J. A. Mejia

The combination of high-resolution X-ray microtomography (HRXMT) image analysis and Lattice-Boltzmann Method (LBM) simulations has demonstrated the ability to describe real multiphase flow problems in fine coal filtration. The single component multiphase flow He-Chen-Zhang LBM model was used to simulate filtration with actual HRXMT images of pore network structures produced in filtration experiments. The analysis performed on coal, silica, and glass bead filter cakes showed that particle shape and wettability are two of the most important factors in the retention of moisture during filtration.

Feb 23, 2014

By T. Hayashi

A sophisticated process of extracting ultrafine sulfide mineral particles of under 1µm size suspended in clay slurry has been developed through studies of electrochemical properties of particle surface. Experimental procedure and data of the process applied to some clay ores containing sphalerite and pyrite, and molybdenite and other sulfide minerals are reported. Discussions concentrated on the function of process reagents, particularly on various modifying reagents, and on the effect of dispersed or flocculated state of ultrafine particles in slurry which affect significantly the performance of the process.

Jan 1, 1982

By Charles L. Kimbell

Introduction Despite the focus on the so-called "high-tech" and service components of the economy, the minerals industry in 1987 continued to provide the world the overwhelmingly dominant share of the total raw material supply for all manufacturing operations. And, in the form of fertilizers and other soil treatment materials, minerals also supplied indispensable raw materials to ensure continued high production of the agricultural and forestry sectors of the world's economy. Moreover, the role of minerals as a source of construction raw materials was essential to that sector. On the basis of preliminary and partial statistics on world output of crude mineral commodities, 1987 appears to have been a year of further recovery from the recessional years of 1981-1983. The value of world crude mineral industry production (all mineral commodities including fuels) apparently advanced about 5% to nearly $1.1 trillion in terms of constant 1983 dollars.' That is significantly above the recently revised 1986 level of nearly $1.05 trillion, but still considerably below the record-to-date high of $1.27 trillion set in 1980, as shown in Table 1. That growth in value took place despite relatively flat world oil prices - oil being the most important component of the aggregate, as it has been for decades. There is insufficient information available to assess the total value of processed mineral commodities (refined metals, refined oil, manufactured fertilizers and the like). But a figure of $2.6 trillion (constant 1983 dollars) would be a quite conservative estimate for those materials derived only from primary or newly mined materials. And an additional, as-yet-unestimated increment should be added for processed materials derived from secondary raw materials - scrap and other reclaimed substances. From a world trade viewpoint, minerals and mineral products dominate in terms of tonnage. For example, in 1985, on a weight basis, mineral commodities including fuels constituted more than 58% of all goods moving through the Suez Canal and 53% of all goods passing through the Panama Canal. These waterways cannot accommodate giant tankers and ore carriers. So an even larger share of total oceanic trade is composed of minerals and mineral products. Yet, in terms of value, the share of the total accounted for by these industrial essentials is much lower than that accounted for by other commodities, most notably sophisticated high-tech equipment and other goods with a relatively high per-pound value. Worldwide data on the value of mineral export trade for 1987 is so incomplete at this writing that it is impossible to assess that actual level. Indeed, the compilation of similar available data for 1986 covers only the exports of nations with developed market economies. In 1985, these countries accounted for only 67% of total world exports of all goods. They accounted for only 41% of world exports of major mineral commodities: crude nonmetals; metal ores, concentrates, and scrap; mineral fuels; nonferrous metals excluding gold; and iron and steel. For these developed-market-economy countries, the value of exports of these major mineral commodities declined by more than 10% between 1985 and 1986. Most of the shortfall came as a result of a 26% drop in the value of fuels exports. If these patterns of

Jan 7, 1988

By T. N. Andersen

The history of gold and silver analyses shows an interesting duality. On one hand, classical chemical and instrumental methods have evolved to meet changing needs, but on the other hand, the age-old and somewhat empirical fire assay has remained a popular tool. Inasmuch as gold and silver generally have been present in ores at low concentra¬tions, methods have been challenged by a need for sensitivity and selectivity coupled with reasonable assay time. A progressive increase in the importance of low grade materials as ore sources has led to the need for improved methods. Assays of these materials are required for process control and accounting in operating plants as well as for guiding research and development activities. The analytical response to these needs is evidenced by numerous reviews published through 1977-¬e.g., cf Kolthoff and Elving (1966), Beamish and Van Loon (1966, 1972, and 1977), Young (1971) , Mallett (1970), and Sen Gupta (1973). In this paper we present a brief sketch of the history and status of various gold and silver methods. A more detailed summary of atomic absorption spectroscopy (AAS) is Given, as this method has gained in popularity more than other assay methods. AAS methods currently in use are summarized and discussed briefly. This paper is not meant to be a detailed review, as are the above mentioned publications. Rather, we borrow from those works and more recent papers to report trends in gold and silver analyses (particularly in AAS). Also, we discuss some selected poten¬tial problems, and problems that have been experienced by this laboratory.

Jan 1, 1981

By Ernest M. Spokes

Starting in 1980, a committee of the National Research Council studied the question of why some underground coal mines are safer than others and what could be done to improve the ones with poorer performance. The results indicated that safety is improved by management commitment to safety, by cooperation between labor and management on safety matters, and by quality training of employees and managers. Younger mines have higher accident frequencies, but are less likely to be killed or permanently disabled by a lost-time accident. Methods for improving safety performance are proposed.

Jan 1, 1983

By Dermot M. Ross-Brown

The objectives of this generic study were to use numerical modeling techniques to determine under what conditions seismic waves generated by an earthquake might cause instability to an underground opening, or cause fracturing and joint movement that would lead to an increase in the permeability of the rock mass. In general, the study showed that moderate earthquakes (up to 0.41 g) did not cause instability of the tunnel or major fracturing of the rock mass. An artificial rock-burst tremor with high accelerations, however, was found to be amplified around the tunnel, and fracturing occurred as a result of the seismic loading in salt and granite. In shale, even moderate seismic loading resulted in tunnel collapse.

Jan 1, 1981

By V. Claremboux

The transformation of raw iron ore into high quality steel can take place via several processes. A general consistent theme involves the upgrading of the iron ores via methods such as flotation and magnetic separation, the preparation of an agglomerate such as via pelletization or sintering, the smelting of the agglomerate into a high grade iron product, and the further refining of iron into specific steel alloys. Each of these steps admit potential for optimizations and alternatives, and the process overall is critical to meeting the world’s continuing iron demands.

Feb 1, 2025

By David A. Milligan

This paper describes the Darwin Silver Recovery project, located 66 km (40 miles) outside of Lone Pine, near Darwin, Inyo County, California. A lead-zinc mine and a flotation concentrator were operated there from 1945 to 1957. By the time the mine was shut down, 1.53 Tg (1.69 million short tons) of tailings had been stored in ponds. An average silver assay of 47 mg/kg (1.38 troy oz/st) of tailings stimulated interest for commercial silver recovery. A heap leach process was developed in 1981 at the Tucson Research Center of Anaconda Minerals Company, a division of Atlantic Richfield Company. Agglomeration techniques were used on the ore since the fine grind did not allow direct heap leaching. Lime and cement were required as binders, Early laboratory tests showed that recoveries equal to those from an agitated leach could be achieved at lower capital and operating costs. Laboratory tests determined cyanide requirements, lime and cement usages, and percolation or leach rates, as well as confirming that a zinc precipitation step could recover the silver from the leach solution.

Jan 1, 1983