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By Paul T. Allsman, Paul F. Yopes

17.1--CURRENT AND FUTURE STATUS OF SURFACE MINING PAUL T. ALLSMAN AND PAUL F. YOPES 17.1.1--CURRENT The history of surface mining essentially is one of mining coal, copper, iron and aluminum ores, of placer mining gold and tin, and of pits and quarries producing clays, gypsum, phosphate rock, sand, gravel and stone. Table 17-1 is a summary of the estimated world and United States production of crude metallic and non¬metallic ores and coal in 1969. It includes estimates of the quantities produced by surface-mining methods. Two-thirds of the 10 billion tons are mined from the surface, ranging from a third of the coal. 57% of the metallic ores, and nearly all clays, stone, sand and gravel. Production by surface methods in the United States, parallels that of the world with one exception: about 90% of the copper and iron ore is mined from the surface, whereas elsewhere only about half the copper ore is surface mined. In Canada, surface mining of the Athabasca tar-sand deposits is a recent large-scale unique operation. In surface mining of coal and, to a lesser extent, metallic ores, much waste is stripped, but in nonmetallic pits and quarries the ratio between waste and ore usually is small. Assuming that the stripping ratio for surface mining in the

Jan 1, 1973

By M. Stuart

The copper-silver-mercury orebody of Gortdrum Mines (Ireland) Limited is located 3 miles north of the town of Tipperary in the Republic of Ireland. A drilling programme from 1964 to 1966 delineated an ore¬body of 4.19 million tons of copper ore assaying 1.19% Cu and 0.75 ozs per ton Ag, which could be mined from an open pit. Testwork having shown that the ore was amenable to conventional flotation techniques, it was decided to build a concentrator of 500,000 tons ore per year capacity. Stripping of the open pit commenced in 1966 and in the autumn of 1967 the concentrator started up. The first shipments of concentrates were made to the smelter in Europe in late 1967. In the spring of the following year, word was received from the smelter that these early shipments contained between 1% and 2% Hg, and that the smelter could not accept further shipments of this quality.

Jan 1, 1973

By D. C. Yang

A practical and economical flowsheet has been developed and demonstrated by integrating the packed column flotation with the GranuFlow process for fine coal recovery. Orimulsion, which was used as an additive, served a dual purpose: first in the flotation and second in the dewatering and granulation steps. The test results on the coal preparation effluent sample show that Orimulsion is flexible and compatible with fuel oil and various frothers used in the packed column. Clean coal with ash contents of 3.0, 3.7, 4.3 and 5.1% were produced from a head sample of 33% ash at combustible matter recoveries of 72.4, 81.1, 87.5, and 89.2%, respectively. Other advantages include high throughput, low moisture, improved handleability, and reduced dustiness of the dewatered coal, thus providing a very significant economic Incentive for the integrated process.

Jan 1, 1998

By C. L. Elmore

This paper describes a new development in the cyanidation of gold ores, which we expect will result in a major improvement in the way many gold ores are treated. The process has evolved through work at Hazen Research, Inc. for Kamyr, Inc. and in brief, the consists of utilizing oxygen rather than air in the carbon-in-1 each (CIL) process. We refer to this improved process for all ores amenable to cyanide leaching as carbon-in-1each with oxygen or CILO.

Jan 1, 1988

By X. Zhu, Chen. L., R. Guru, M. Peiravi, M. Mohanty, L. Ackah, B. Xu

"The overall goal of this study is to develop a suitable flow sheet to extract rare earth elements (REEs) from coal ash. A total of 14 coal samples of different ranks were examined for REE concentration, and an anthracite coal sample with the highest REE concentration of more than 700 ppm in the coal ash was selected for REE extraction tests. This paper reports on the results of the experimental program completed in the first part of the study, which included hightemperature leaching with nitric acid followed by solvent extraction tests using various organic extractants, namely, tributyl phosphate, Cyanex 572, di-(2-ethylhexyl)phosphoric acid (D2EHPA) and their combinations. A 4×2×2 experimental design was used to conduct a total of 32 high-temperature leaching tests by varying acid molarity at four levels, solids content at two levels and leaching time at two levels. The highest recovery rates of 90 percent for light rare earth elements (LREEs) and 94 percent for heavy rare earth elements (HREEs) were obtained from the optimum leaching test conditions while maintaining impurity recovery to the leachate at less than 40 percent. D2EHPA was found to be the best extractant in this solvent extraction test series, providing an REE recovery rate of nearly 99 percent.IntroductionGlobal demand for rare earth elements (REEs) and other strategic metals is increasing rapidly due to their use in a variety of advanced technological applications, with more than 100 kt of rare earth oxides used worldwide on an annual basis. The United States has less than 10 percent of the world reserves of REE mineral deposits, and in 2013 imported more than 60 percent of its rare earth oxides from other countries, mainly China (United States Geological Survey, 2017). China’s institution of export quotas has significantly reduced supply to the United States, raising the urgency of finding new ways of producing REEs and/ or substitutes. Coal combustion byproducts, which are usually discarded as waste materials, are known to contain REEs in low concentrations that could be extracted with a suitable process flow sheet. This may be a worthwhile route to pursue, considering the short supply of rare earth minerals and the abundance of coal ash in thousands of ash ponds in the United States. More than 110 Mt of coal combustion byproducts are produced annually in the process of satisfying the country’s need for electricity (American Coal Ash Association, 2016), and less than 50 percent of these byproducts are being successfully used in various applications, with the remainder dumped as waste materials in landfills and ash ponds."

Jan 1, 2017

By R. J. Matetic, Peter G. Kovalchik, Jeffrey Shawn Peterson

The National Institute for Occupational Safety and Health (NIOSH) has initiated a study of a roof bolter to reduce noise exposure to mine roof bolter operators. An important segment of this research entails determining the affect of various drilling configurations on the performance (penetration rate) and sound power emissions when drilling into granite. Test conditions included various combinations of rotational speeds and thrusts; hex and round drill steels of one inch (1.) and one and three-eighths inch (1 3/8.) diameters; vacuum and wet conditions; and using drill media of differing compressive strengths. This paper will detail the affects of each of these on the performance and sound power level emission. When drilling into granite, it was found that wet drilling generated lower sound power levels and performed better than vacuum drilling.

Jan 1, 2005

By T. J. Smolik

The Golden Sunlight Mine started full-scale operations in February 1983, with a conventional open-pit mine supplying 4464 tonnes (5000 tons) per day of milling ore. After crushing and grinding, the ore is leached with cyanide solution in large agitation tanks. Soluble gold values are removed from the sand portion of the leached ore with five stages of countercurrent washing cyclones. After thickening of the cyclone-wash overflow slurry, the gold is recovered in activated carbon with a six-stage carbon-in-pulp circuit and a five-stage upflow carbon column circuit. Pressure stripping, carbon reactivation, electro-winning and refining complete the gold recovery process.

Jan 1, 1984

Asgco’s design of the Arrowhead Ceramic Lagging provides solutions to problems experienced with conveyor belt slippage around the drive pulley and severe wear problems on snub and bend pulleys. Asgco has developed a range of pulley lagging from ceramic, drive rubber and non-drive rubber lagging that is available in abrasion-resistant SBR and MSHA grade rubber for conveyor pulleys from slow belts all the way through to high-speed, high load belts. There is a growing need for a maintenance-free and reliable pulley lagging to ensure conveyor belts run to their highest efficiency.

Jan 1, 2006

By Dan Wang, Qiuju Li, Xiao Guo

The chemical states and ions interaction were significant interest to understanding columbite mineral/acid solution interface dissolution and reaction. The present research work was focus to explore the specific cations ( Nb5+, Fe2+, Fe3+) distribution near the ferrocolumbite mineral/acid solution interface, and determine these cations leaching sequence in sulfuric acid solution. X-ray photoelectron spectroscopy had the potential to provide detailed dissolution information by resolving chemical state and ion distribution of ferrocolumbite during sulfuric acid leaching process. The binding energy decreased in sequence as Nb5+- O < Fe2+- O < Fe3+- O, and increased in sequence as Fe3+- SO4 < Fe2+- SO4 < Nb5+- SO4 which revealed Nb in ferrocolumbite mineral more easily leached comparing to Fe. The ratio of Fe2+- O/Fe3+-O on leaching residue decreased, and Fe2+- SO4/Fe3+-SO4 ratio increased as sulfuric acid contraction increasing suggested that the Fe2+ oxidized to Fe3+ and released Nb from mineral and dissolved into leaching solution. The ratio of Nb/Fe was lower 0.07 with sulfuric acid contraction increasing which meant Nb dissolution promoted by oxidation of iron. The dissolution mechanism of Fe element in ferrocolumbite mineral was Fe2+- O broken and generated Fe2+. Fe2+ was oxidized to Fe3+ in concentrated sulfuric acid leaching solution. The dissolution mechanism of Nb in ferrocolumbite was that Nb5+- O was directly digested by H+, and the released Nb5+ complex with SO4 2− ion formed cation − anion pairs. The coordination of formation Nb5+- SO4 pairs and oxidation Fe2+ in mineral could promote ferrocolumbite dissolution.

Aug 5, 2023

Joy Mining Machinery has developed a new generation of ultra-heavy shields for Anglo Coal Australia?s Moranbah North Mine in the Bowen Basin region of Queensland. These are the largest two-leg longwall shields yet produced by Joy. The longwall at Moranbah North posed a number of challenges, among them a thick, inclined, sometimes undulating seam with increasing depths. The result of this was the need for larger, heavier, more powerful roof supports. Knowing that future longwalls would be going deeper, mine management determined that shield yield ratings of at least 1,750 t (1,930 st) was what would be required.

Jan 1, 2011

By Eduardo Poltronieri Trés, Anderson Denadai Thomazini, Rodrigo Boyer Fernandes, Francisco de Assis Dutra Macedo, Gilvandro Bueno, Maycon Athayde, Rossano Augusto Pilon Nunes

The earliest industrial application of high pressure grinding rolls (HPGR) at comminution was in 1984 in the cement industry. Since then, the equipment has been widely applied in mining activities. Despite the rapid spread across the industry, several challenges are still present in the equipment’s application, especially considering the complex ore breakage behaviour reported for this process. The pellet feed’s HPGR comminution was recognized as fundamental to efficiently increase the particle surface area (e.g., blaine specific area, BSA) at a lower energy and water consumption level (Chapman et al. in J Southern Afr Instit Mining Metall 113:407–413, 2013). The present study considers a novel milling process applying only HPGR as a re-regrind stage after concentration. The amount of successive ground product recirculation into the machine to achieve the required particle size for the pelletizing process was investigated. The study compared the ball wet milling process with the innovative processing technology for hematite–goethite ores. Green pellet balling and induration processes were simulated in bench and pilot scale. The milling results showed a considerably steep increase in BSA after each recirculation step into the HPGR, although compared with the ball-milled product the size fraction <45 μm% increased a modest five percentage points after three recirculation cycles, remaining steady until the last recirculation step. As a result, the green pellet generated presented higher concentration of pellets between 10 and 16 mm (%10-16 mm), with a higher drop number than typically observed when produced with ball-milled feedstock. Consequently, on the induration process, a higher pellet deformation was observed during the pot grate loading. Despite that, the fired pellets still presented an outstanding performance in cold crush strength (CSS) considered suitable to an industrial application.

By Cesar A. Busnardo

The carbonatite orebody in Jacupiranga is situated some 230km (140-mi) southwest of Sao Paulo and is mined by Serrana S/A de Mineragao, producing an apatite concentrate for fertilizer production and a calcite tailing for cement manufacture (see Figure 1). The orebody (Table 1) is mined by open pit and the total production is 4.5 million mt/year of carbonatite ore with a further 2.2 million mt/year of overburden. The carbonatite low-grade ore (Table 2) is fed to the concentration plant at 460 mt/h , comprising of four parallel lines of grinding, by rod mills 2.7m x 4.5m (9 x 15-ft), operating in closed circuit with hydrocyclones. The grinding circuit product is deslimed in four stages using hydrocyclones and the deslimed product is conditioned with corn starch and subsequently floated, using fatty acids as collector to, recover the apatite.

Jan 1, 1985

By George S. Koch

We evaluate the exploration effort by diamond drilling for zinc in central Tennessee and southern Kentucky through a statistical analysis comparing the Middle Tennessee district with the older Tri-State and Upper Mississippi Valley districts. All of the ore deposits are of the Mississippi Valley type and are similar geologically. Through statistical analyses we attempt to answer these questions: Had the drilling density in the Middle Tennessee district been applied to the Tri-State district, how much of the ore in the Tri-State would have been discovered? Had this drilling been done in the Upper Mississippi Valley district, how much of the ore in that district would have been found? Which of these two older districts does Middle Tennessee more closely resemble in intensity of zinc mineralization? Is more drilling warranted in the Middle Tennessee district? Our data base includes tonnage and area distributions of ore deposits in the Tri-State dis¬trict, sizes of ore bodies and probabilities of their recognition in the three districts, and data for the Elmwood mine in the Middle Tennessee district. Our statistical analysis considers the consequences of drilling holes in the three districts on square grids at coarse, intermediate, and fine spacings. We conclude that the drilling pattern assumed for Middle Tennessee would have found some but not all of the ore in the two older districts. We believe that in intensity of mineralization Middle Tennessee more closely resembles the Tri-State than the Upper Mississippi Valley district, and that more drilling is warranted in the Middle Tennessee district.

Jan 1, 1979

By A. G. Mayton, L. Adler

The paper under discussion provides an excellent and concise study of compartment ergonomics for thin seam equipment. However, in accomplishing this, some very important operational aspects were ignored. Since these are likely to be determinant, the authors&apos; response is solicited. The novel shuttle car with its cross-car, end-mounted compartment is operationally very different from the current one. The latter can be considered a highly mobile extension of the continuous miner or loader, with a pass-through conveyor, dump boom, and extra storage. As such, the vehicle&apos;s kinematics are the simple "I," or shuttle pattern, bent for going around pillars, with an intermediate stop at the "change-out point" (Adler, 1986 ). The action of the cable reel adjusts well to this pattern. The proposed shuttle car&apos;s motion either superimposes a "Y," time is lost (5 seconds) for each cycle, space is needed, line of sight is compromised, and a cable anchor is probably required at the dump. A chute is almost prohibitive in construction time and cost. The lack of a dump boom further curtails flexibility in the proposal. The value of a standard hand and opposite standard hand configuration also needs consideration. Many front-end loaders have a rocker (overshot) capability that is designed to achieve an "I” pattern. And crawler loaders sometimes use a side dumping bucket variant for the same purpose. These examples indicate the pattern&apos;s importance. For underground, thin seam application, the ram car has become popular. This is an articulated truck, battery-powered, and with an ejector dump. Its operational patterns would be similar to the novel shuttle car, except without the loading flexibility provided by a conveyor. Since the cab location of the proposed shuttle car largely obviates some of the major advantages of the present shuttle car, the question arises whether this configuration could be adapted to the current ram car and scoop

Jan 1, 1991

By L. Adler

The paper under discussion provides an excellent and concise study of compartment ergonomics for thin seam equipment. However, in accomplishing this, some very important operational aspects were ignored. Since these are likely to be determinant, the authors&apos; response is solicited. The novel shuttle car with its cross-car, end-mounted compartment is operationally very different from the current one. The latter can be considered a highly mobile extension of the continuous miner or loader, with a pass-through conveyor, dump boom, and extra storage. As such, the vehicle&apos;s kinematics are the simple "I," or shuttle pattern, bent for going around pillars, with an intermediate stop at the "change-out point" (Adler, 1986). The action of the cable reel adjusts well to this pattern. The proposed shuttle car&apos;s motion either superimposes a "Y," time is lost (5 seconds) for each cycle, space is needed, line of sight is compromised, and a cable anchor is probably required at the dump. A chute is almost prohibitive in construction time and cost. The lack of a dump boom further curtails flexibility in the proposal. The value of a standard hand and opposite standard hand configuration also needs consideration. Many front-end loaders have a rocker (overshot) capability that is designed to achieve an "I" pattern. And crawler loaders sometimes use a side dumping bucket variant for the same purpose. These examples indicate the pattern&apos;s importance. For underground, thin seam application, the ram car has become popular. This is an articulated truck, battery-powered, and with an ejector dump. Its operational patterns would be similar to the novel shuttle car, except without the loading flexibility provided by a conveyor. Since the cab location of the proposed shuttle car largely obviates some of the major advantages of the present shuttle car, the question arises whether this configuration could be adapted to the current ram car and scoop.

Jan 1, 1990

By David R. Reid, Lawrence W. Talbot

INTRODUCTION In the mining industry, timing in land acquisitions can be of the essence. In order to secure promising lands, deals are often negoti- ated quickly and evidenced by letters of intent containing what the parties feel are the essential terms of the deal. In some cases, a company is willing to acquire land only if it can lock up a number of promising properties, and so a "non-binding" letter of intent is used to formalize the essential terms, while leaving the company without legal liability. Later, the letters of intent will be sent to a lawyer to prepare a formal acquisition agreement. Many times, how- ever, especially in a land acquisition rush, another company will attempt to better the deal prior to the execution of that formal agreement, and the first company will be forced to rely on the initial letter of intent, only to find out to its chagrin that it has no deal In other cases, the company holding the desired property is another mining company, and the negotiation of an option or joint venture is the only way the first company can acquire an interest in the desired land. In order to make its offer more attractive, it may have to reveal confidential or proprietary information about the property or the surrounding lands. Here, too, letters of intent are often used to formalize the essential points of the agreement. Once again, however, prior to the execution of a formal joint venture agreement, the transaction may collapse and the letter of intent prove to be only that. In this paper, the authors examine the dangers associated with the use of letters of intent and the specific provisions courts look for to find a binding contract, and consider how to increase the

Jan 1, 1988

By Y. Guo, C. Cao

"China is rich in tungsten resource, but they are mainly associated minerals. The similar flotability of scheelite, fluorite, and calcite resulted in the difficult separation by flotation. This work summarized the current situation and the development of flotation reagents, technological process, and mineral processing equipments in China. Fatty acid served as the collector and water glass was the depressant to expand the flotability differences in traditional flotation technology. However the water glass inevitably influenced the flotation of tungsten minerals to a large extend, and the suppressed fluorite was difficult to recover by flotation. Abundant water glass lead to the bad settleability of the tailings and the tail water was difficult to circulate, resulted in serious environmental problems. Recent study proved that the selectivity of benzene armour hydroxyl oxime acid (BAHA) salts was adequate for the separation of tungsten minerals from fluorite, calcite and most silicate minerals without any depressant. By this way, sodium silicate was canceled completely in tungsten flotation, greatly improving the recovery of tungsten and the environmental problems caused by tail water treatment would be solved fundamentally. TUNGSTEN RESOURCES AND DISTRIBUTION IN CHINA China is rich in tungsten resources and the proved reserves accounted for 60% of the world's reserves [1]. However the wolframite has been dried up and the scheelite resources had become the main resource of the tungsten metal. Table 1 showed the most large and superlarge scheelite deposits in China. China has more than 40 large and superlarge scheelite deposits and the total metallic deserves is more than 3 million ton [2]. But most of the deposits were low-grade and the associated relationship was complicated. For example, scheelite was usually associated with wolframite, molybonite, bismuthinite, pyrite, fluorite, and calcite in Shizhuyuan and Yaogangxian mine."

Jan 1, 2016

Residential and commercial plumbers in the United States were introduced to Viega?s copper press technology in 1999. In short, the technology allows plumbers and installers to join copper pipe securely in four to seven seconds on pipe sizes of 1.2 to 10 cm (0.5 to 4 in.) by pressing the connections with specialized tools and fittings rather than through sodering or welding. The water- and air-tight technology, first introduced in Germany in 1989, includes three different sealing elements, a variety of materials and a selection of configurations. By eliminating the need to thread or solder pipe, connections and repairs can be made quickly and securely. Installations are also much quicker and as secure as traditional methods.

Jan 1, 2012

By Jon G. Baird

The suggestion of the use of measurements of trace amounts of mercury as a guide to the location of sulphide ore deposits was first made by the Russian, A. A. Saukov (1), in 1.946. Since Saukov&apos;s original work, many others have studied the abundance of mercury in nature, the association of mercury with sulphide ores and methods by which very minute quantities of mercury can be measured in air, soil, rocks, water and plants. The most abundant of the mercury bearing minerals is cinnabar (HgS). Native mercury is also found and sulpha-salts like tetrahedrite are known to have important mercury contents. Other sulphides of base metal deposits contain mercury in amounts ranging from parts per million to as much as one or two percent. (2) The mercury content of sulphide-free rocks is usually less than a few hundred parts per billion (1 ppb - 10-9), Soils usually contain less than 100 ppb and water less than 1 ppb of mercury. Normal atmospheric air contains about 1 nanogram (10-9 grams) of Hg per cubic metre although higher concentrations can be observed near mercury occurrences, sulphide deposits and volcanic exhalations.

Jan 1, 1973

By P. Eng. Daniel Kelly

INTRODUCTION The Astoria property is located in the prolifically mineralized Abitibi greenstone belt and is one of the most advanced projects presently under development by Yorbeau Resources Inc. This property, which hosts the Astoria gold deposit, is located in the southern part of Rouyn township, Abitibi area, Quebec, 4 km south of the city of Rouyn-Noranda (Figure 1). The Astoria deposit has been the subject of underground development for over a half century, beginning with Granada Rouyn Mining Co. in the 1930&apos;s and followed by Astoria Rouyn Mines Ltd. in the 1940&apos;s. Yorbeau Resources Inc. acquired the property in 1984 and has, since then, conducted numerous exploration programs on this gold deposit. The diluted reserves of the Astoria deposit are estimated at 1,3 million metric tons grading 6,14 grams of gold per metric ton (1.4 million st at 0.18 oz/st). This reserve figure is based on the results of surface and underground exploration carried out from January 1986 to June 1987 and includes ore in the proven, probable and possible categories. This paper is divided into two sections. The first part includes a summary of the geological environment including a description of the gold bearing zones and a short discussion on wall rock alteration. The second part of this paper reviews the underground work and the objective of the ongoing exploration program.

Jan 1, 1988