Search Documents

The Subtropolis mine is a room-and-pillar mine extracting the Vanport Limestone near Petersburg, Ohio. In February 2018, mine management began implementing a heading reorientation to better control the negative effects of excessive levels of horizontal stress. The conditions in the headings improved, but as expected, stressrelated damage concentrated within crosscuts. The mine operator has worked to lessen the impact of the instabilities in the outby crosscuts by implementing several engineering controls. With the implementation of each control, conditions were monitored and analyzed using observational and measurement techniques including three-dimensional (3-D) LiDAR surveys.

Jan 7, 2020

By P. A. Korpi

In March of 1978 the first set of Angular Spiral Liners utilized in grate discharge ball mills for wet grinding was put into service in the San Flanuel Concentrator of Flagma Copper Company. The use of these liners has decreased grinding media consumption by 19.2% and grinding energy consumption by 15.8%. In addition a 1.1% increase in grinding throughput is being realized through the use of the system. This paper describes the Angular Spiral Lining System and reviews the test program at the San Manuel Arizona Concentrator. Operating parameters are discussed in addition to the current testing program to futher optimize the system.

Jan 1, 1982

By Jerry C. Tien

Changes and the pace of change in China’s coal industry have been extraordinary during the past several years. At least 35 of the 94 former coal bureaus have been restructured into different mining companies and groups. Some of the more productive and efficient ones were further strengthened through consolidation and expansions. And several have even formed, or are in the process of forming, strategic alliances with utility companies, railroads, ports and chemical companies to secure additional reserves and coal sales. In addition, the improvement in coal pricing during the past two years has enabled China’s coal industry to move ahead with some needed changes. Coal mining accidents, though, remain a major concern for the Chinese government. Accidents remain high even though the government has made efforts to shutdown more than 55,000 unlicensed, unsafe small coal operations throughout the country.

Jan 1, 2003

By S. R. Dismukes

Mining is likely to be targeted by The United States Environmental Protection Agency (“EPA”) as one of its key enforcement targets for fiscal year 2002-2003. Identifying the mining industry as an enforcement target, coupled with an increase in enforcement activity in recent years, places each mining operation at increased risk of receiving enforcement attention. A properly developed and implemented Environmental Management System (“EMS”) tailored for your operation is invaluable in reducing the risk of incurring liability for non-compliance. At the heart of an effective EMS is an audit program that checks the company’s compliance with environmental requirements. In addition, audit privilege (in select states), voluntary self-disclosure, and the attorney-client privilege serve as very effective tools for managing those liabilities that may arise during auditing a well-developed program. Of course, these latter tools are effective only if the auditing program is properly structured and properly managed. EPA and some states also provide varying degrees of immunity for environmental violations that are voluntarily disclosed in writing by the company. However, self-disclosure laws and policies typically prescribe stringent requirements for parties seeking to take advantage of them. For example: U.S. EPA has recently extended the time period in which to provide full written self-disclosure to 21 days. However, U.S. EPA’s revised Self-Disclosure guidance also addresses when a company obtains knowledge of a violation for purposes of triggering the 21-day clock and specifically extends the knowledge requirement to include the company’s agents and consultants. This expansion increases the difficulty companies may have in clearly defining and managing when they obtained knowledge. This difficulty increases the importance of managing factual development and the strategic use of other

Jan 1, 2001

By CADEN VITTI, Barbara J. Arnold

Mine tailings, the byproduct of mining and mineral processing, are increasingly mass produced as a result of increased demand for metals and minerals as well as the advancement in technology that allows for the exploitation of lower-grade ores. Lower grades can increase the volume of tailings that may contain new gangue minerals that should be evaluated for the presence of critical minerals and other valuable metals. The practice of reprocessing, while relatively new, is crucial to reducing environmental damages, obtaining valuable critical minerals from waste, and contributing to more sustainable repurposing and disposal methods. With the increase in tailings dam failures in recent years, there is a large motivating factor in remining and removing the potential hazard to benefit the safety of potentially impacted communities. In analyzing the perspectives of various domestic and international studies, this literature review will determine the feasibility of reprocessing and reutilizing mine tailings waste for a more sustainable future while exploring current practices that have benefitted ecosystems and communities.

Jan 1, 2022

By R. Woods, O. A. Kiehn, C. A. Born, F. N. Bender

Development of the flotation reagent scheme at Climax Molybdenum Company's mine at Climax Colorado is reviewed. Features of the mineralogy, milling practice and background of reagent changes are outlined. Special attention is given to the hitherto unpublished details of the application of depressants for copper and lead impurities. The present rougher flotation reagent scheme utilizes a neutral hydrocarbon oil, low in unsaturates and wax, as collector with a sulfated coconut oil emulsifier and pine oil frother. Lime and sodium silicate are used as rougher conditioning and slime dispersant agents. Chalcopyrite and galena impurities are de- pressed in both rougher and cleaner plants by stage addition of Nokes reagent and sodium cyanide to yield a metallurgical grade molybdenite concentrate containing greater than 90% molybdenite and less than 0.5%, 0.1% and 0.05% iron, copper and lead impurities, respectively.

Jan 1, 1976

By John Zeni

In Australia during the 1990s, Zeni Drilling took on several demanding shaft boring contracts. This paper describes the safety, operational, technical and environmental advantages derived through the implementation of mechanized boring methods for two of these projects. The paper first describes a 3-meter (10 ft) diameter access shaft blind bored from an underground location to 440 meters (1,444 ft) deep for a gold mine in Tasmania. The construction of a 5.8-meter (19 ft) diameter, 515-meter (1,690 ft)deep ventilation shaft for a longwall coal mine in New South Wales is also described.

Jan 1, 2001

By John D. Morton, J. H. LaVerne Palmer, Douglas J. Belshaw

An extensive programme of ground instrumentation and observation was carried out for the West Duff in Outfall Sewer tunnel project prior to and during construction, to establish the performance characteristics of the rock through which the tunnel and appurtenant openings were dug and to examine the nature of the lining-to-ground interaction. The existence of high horizontal residual ground stresses was confirmed, and values established by overcoring. Rock deformations and stress changes were monitored during tunnelling. Permanent stress and strain monitoring devices were set into the final lining and these are continuing to operate. INTRODUCTION The site is located on the north shore of Lake Ontario at Pickering, some 20 miles (32 kilometres) east of Toronto, Canada where a variable thickness of glacial or interglacial sediments overlies bituminous shale bedrock of. the Collingwood Formation which is lower Ordovician age. Approximately 50 feet (15 metres) of glacial cover exists at the shaft, though this thins abruptly at the regressing cliffed shoreline such that several small areas of exposed bedrock exist in the lakebed. The general location, overall geological section and detailed site plan and profile are illustrated in Figs.1,2 and 3 respectively. General properties of the rock as established during an extensive test drilling and site investigation programme are listed in Table 1, while stress determination by USER overcoring stress meter device are given in Table ll. These data formed the basis of analyses which were done to examine the intended outfall design, and to detail the construction procedure and the observational instrumentation programme.

Jan 1, 1979

By Paul D. Klipfel

Introduction Mineral exploration interest, principally for gold, in the south-western Pacific has surged to new proportions. This is primarily due to the application of epithermal exploration concepts in the Australian-Oceana region. Other factors that have contributed to the high level of exploration interest include governmental policies supportive of mineral exploration, along with relative ease of tenure access and a relatively short bureaucratic process. This paper highlights exploration and development activities in the North Island of New Zealand, Fiji, Vanuatu, the Solomon Islands, and Papua New Guinea (Fig. 1). It provides a framework to understand the overall recent enthusiasm that has been brought to the south Pacific by explorationists. Through these recent developments, it is clear that the south Pacific region will become a significant gold producing area and thereby worthy of attention and study. Papua New Guinea alone is the free world's seventh largest producer (Table 1). And, with the addition of production from deposits presently being developed, this status is likely to be raised. History Gold was first noted on various Pacific islands in the late 1500s by Spanish explorers. They thought they had reached the legendary King Solomon mines. Since then, the history of prospecting in the southwest Pacific has coincided with the colonization of the region. Settlers in New Zealand extensively mined alluvial and lode gold deposits starting in the 1850s. The spread of European colonization to the more remote Pacific islands from 1880-1940 was accompanied by varying degrees of prospecting activity by planters, traders, and settlers. Some were successful, others may have been successful, but never returned due to hostile indigenous peoples or disease. In general, records of such prospecting activity are meager and exploration leads are, in some cases, gained through local village folk memory. Most early discoveries were alluvial finds. These led to placer operations, particularly in New Zealand, the Solomon Islands, and Papua New Guinea. Continued prospecting located lode deposits such as the Morobe Gold-field of Papua New Guinea, the Coromandel Peninsula of New Zealand, and the Emperor of Fiji. Some areas were prospected thoroughly. Yet others, such as Vanuatu, remained relatively unexplored until the present exploration surge began. During World War II, interest in minerals was diverted. It was renewed significantly until the middle 1960s and early 1970s when regional porphyry copper exploration was conducted.

Jan 10, 1987

By A. Moergeli

The Swiss are building the world’s longest tunnel, the 57-Kilometer (35-mile) long Gotthard Base Tunnel. Lot 252, Tunnel Amsteg: Two Hard Rock Tunnel Boring Machines (TBM) crossed hydro-thermally decomposed granite. While the East TBM advanced slowly but steadily, the West one got stuck for five months and had to be recovered by special means and methods. Both TBMs have finished their more than 11-Kilometer (7 miles) long drives successfully. Lot 360, Tunnel Sedrun: For the first time in tunneling, roadway support machines are used through most challenging, squeezing geology. They constantly advance in full face mode for about one Tunnelmeter/24 hours.

Jan 1, 2007

By C. S. Kucukkaragoz

An ilmenite concentrate was reduced in the solid state with carbon under argon atmosphere at temperatures between 1000oC and 1400oC. The ilmenite concentrate and 50% excess carbon were reacted to achieve the highest attainable degree of reduction at each temperature and the reaction products were subjected to a series of analytical work by optical microscopy, X-ray diffraction analysis and SEM ( EDS) analysis. The ilmenite remained unaltered at 1000oC and had a slight change in its composition at 1050oC. A secondary oxide phase containing metallic nuclei was detectable at 12% reduction at 1100oC. The reduction of TixOy took place in a sequence changing the y/x ratio from 2.0 to a value less than 1.0 at 84% reduction at 1400oC. Metallic phase consisted of Fe and C initially and started to include Ti at the later stages. Complete reduction of TixOy to metallic Ti was not possible at these temperatures.

Jan 1, 2005

By John Dasher

In 1980, some US cars were designed and built to metric dimensions; wine and gas were sold by the liter; and the March of Dimes Walkathon was measured in kilometers. Although the US Congress has taken a ''soft" approach to metrication, and public resistance to the idea remains strong, the use of metric units is becoming more and more widespread. As the minerals industry becomes more international in scope, US mining companies are converting to the metric system-particularly those companies with business interests overseas.

Jan 2, 1981

By Daniel H. Isreal

Because the federal government owns and controls nearly 80% of the most valuable oil shale reserves in the West, it is inevitable that federal leasing and siting will play a prominent role in development of an oil shale industry during the 1980s. Also, because of recent enactment of the Synthetic Fuels Corp. authorizing up to $88 billion in loan and price guarantees-federal financing will provide the critical incentive to permit private investment in a still infant industry.

Jan 1, 1981

By Jan Luca Grunow, Ansgar Bendiek, Klaus Böde

According to the Markowitz portfolio theory the value of a diversified portfolio is higher than the sum of the parts of a portfolio, which is an important consideration for the correct valuation. This is valid for real estate portfolios as well as for mining assets (or enterprises). This paper analyses the application of the portfolio theory to a diversified portfolio of assets in the real estate industry and draws conclusions on further research work to be done in the minerals industry. The volume of real estate transactions is increasing over recent years. As such, the nature of those transactions is constantly changing and in some cases portfolios become more heterogeneous as they are composed of different property categories, e.g. locations and types of use. This makes their economic evaluation more difficult. This paper focuses on the acquisition of a fairly heterogeneous real estate property portfolio purchased by “Commerz Real” in Germany in Q4 2019. For economic evaluation the widely used Markowitz portfolio theory (Markowitz, 1952) was applied. It was investigated whether diversification effects could achieve added value in the form of a reduction in risk compared to the sum of their individual components. As a result the findings of this research could be applied to other heterogeneous real estate transactions and even to mine property portfolio or PPP1 project portfolio transactions.

Jun 25, 2023

By Dru Brown

More than 150 Mt (165 million st) of material crashed down at the Bingham Canyon Mine (Rio Tinto/Kennecott Utah Copper) near Salt Lake City, UT on April 10, 2013. The mine, one of the largest openpit mines in the world, ceased operations and evacuated personnel prior to the slide when it was discovered that material was moving at a rate of 5 cm/d (2 in./day). The slide destroyed the mine?s visitor?s center, buried several pieces of large mining equipment and severely hampered production. The Kennecott Utah Copper Corp. immediately began to assess the damage and look for options to reestablish operations. The highly unstable ground ? emphasized by another minor slide in September 2013 ? makes any cleanup efforts extremely dangerous. With terrain too dangerous for human operators, Kennecott was forced to look for alternatives that would help the company work on the treacherous slopes of the landslide while also keeping personnel safe.

Jan 1, 2014

By Thomas J. Neil, O&apos

Mine land reclamation is a comparatively new science-Although some mining companies point with pride to reclamation efforts of 20 to 30 years ago these were the exception rather than the rule. In the last ten years the skyrocket of environmental awareness has been awesome to behold. Future shock gripped mine operators everywhere as they struggled to cope with rapidly changing and escalating demands. The initial result was that two divergent points of view became dominant. Environmentalists said, "Put it back the way it was," and the miners responded, "Let's grow some weeds and hide it." These views are not surprising as they represent rather obvious alternative responses, albeit at opposite ends of the decision spectrum. The former case has prevailed more often than the latter, as most state and federal legislation -- both proposed and passed -- has required drastic alteration of the post-mining landscape so that evidence of prior mining is largely obliterated. An exception to this has been in porphyry copper country where the infrequent abandonment of mines has given emphasis to the second philosophy -establishing vegetative cover on mine waste materials. Now, it should come as no revelation to most mining people that both of these approaches to mine reclamation suffer from serious drawbacks when applied to open pit copper mines. First, whereas waste dumps and tailings dams can be vegetated with some aesthetic benefit, the massive presence of copper mining operations remains very prominent. It is difficult to conceal an open pit copper mine. Second, returning open pit copper mines lands to their original topography and productivity is simply not a reasonable alternative.

Jan 1, 1976

By S. Yerel

Block cutter machines have been extensively used in natural stone industry, which is a sub-section of mining industry. In this study, the costs occurring in plate losses cut from Bilecik beige marble with a circular saw block cutter machine have been predicted using Statistical Process Control (SPC) techniques. One of SPC techniques is Shewhart control charts such as mean control chart. These charts have been efficiently at determining the plate losses. The costs occurring in plate losses have been calculated by using the result of Shewhart control chart. Finally, this study presents the necessity and usefulness of SPC techniques in assessment of natural stone industry.

Jan 1, 2010

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

By M. Ge

Pattison Mine is a small sandstone mine located in Iowa. The sandstones produced by the mine are not common construction and aggregate materials. The stones are used to produce a special type of sand for hydraulic fracturing, a critical technique for recovering tight gas and shale gas. These sandstones are very different from the minerals and rocks which have been studied extensively in mining. On the one hand, they are brittle as characterized by an unusually high friction angle, up to 69°, and steeply curved failure envelopes. On the other hand, they are friable, possessing extremely low, and in most cases zero cohesion. The scarcity of the ground control techniques for this particular mining environment has created many difficulties for the mine operators. In order to resolve these problems, a research program was set up by the mine and Missouri University of Science and Technology. This paper discusses the preliminary results of this investigation.

Jan 1, 2012

By Lester E. Sutton

The past three years have been the most difficult period in the modem history of the barge line industry. Having withstood the fuel cost run ups of the late 1970s and the imposition of inland waterways system user fees, the industry has struggled more recently with an overcapacity problem of unprecedented proportions. In responding to these challenges, the industry is undergoing important long-term structural changes, with the various individual barge lines pursuing an array of divergent long-term business strategies. This paper discusses these strategies in terms of their probable impact on the industry as a whole, and argues for the survival of a competitive number of large, national, independent barge lines as the outcome most in keeping with the long-term interests of the mining and minerals industry.

Jan 1, 1986