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By John Hickey

Management teams at mining companies begin to ask themselves whether to take a company public and, if so, how to do it as they approach the normal threshold for going public in terms of revenue and operating performance. Today, the expense of going public generally suggests the company has at least $20 million in annual revenue and at least $2 million in cash. The revenue number can be lower for mining companies with large reserves. In order to properly attract the investing public, the company must also be operationally strong with robust prospects. The company should have a strong management team and a consistent history of double-digit growth that will continue into the foreseeable future. Assuming the thresholds are met, a company?s management needs to weigh the pros and cons of going public.

Jan 1, 2012

By James Carroll, Lance Heyer

This paper describes the shaft design and construction for a 72-inch microtunnel under 14 active railroad tracks in Avondale, Louisiana. Initial shaft design for a deeper tunnel alignment considered secant piles with a jet grout plug. Final design for a shallower tunnel alignment included contractor input with support consisting of braced sheet piles with a jet grout plug. The authors further elaborate on jet grout implementation in very soft organic clay soils and the practical limitations of jet grouting. This paper emphasizes how all project participants worked together to utilize value engineering and alternative delivery on a unique tunneling project with a focus on temporary shaft support.

Jun 23, 2024

By Daniel C. McLean

Chemistry plays a more important role in milling operations than is generally recognized, particularly in fluid- solid separation processes. Chemical aspects are also very important insofar as plant water quality is concerned, and in the manner in which this water quality effects plant design and operation. Aside from the inherent chemical characteristics of plant water, the mineral preparation industry is becoming increasingly more dependent on the use of mining chemical reagents--relatively new to the coal industry, but items of I standard usage in complex metal recovery plants. These chemicals have many useful properties and can produce significant improvements in operations and metallurgical efficiencies when used properly and intelligently. They can produce poor results and sometimes severe losses when used improperly. Most reagents are relatively expensive on a per pound basis, hence costs can be excessive if they are used wastefully or inefficiently.

Jan 1, 1968

By Joseph W. Kupfner

It is a recognized fact that a good maintenance program is a pre-requisite for minimum delay costs and maximum availability of equipment. To develop such a program and to make it effective, one must establish detailed instructions pertaining to inspections, lubrication, servicing, and/or replacing of various parts. A schedule must also be established for these maintenance checks, whether they be weekly, monthly, or whatever period is essential for the equipment. The number of tasks to be performed becomes monumental, and the administration is beyond error-free human capacity. It is for this reason that the computer must be an essential element in any efficient and economical preventive maintenance program. The evolution of a computerized maintenance program began some 18 years ago in the Mining Division of USSteel. It started with a manual system of preparing cards containing preventive maintenance instructions that had to be performed on some regular basis. We were very quickly overtaken by the massive task of administration and distribution of instruction cards to the users. The task became insurmountable as more mines were added to the system, mines that were spread over a large geographic area. It also became evident that the ability to make changes in equipment assignments and in the "what to do" instructions would require more time than had been anticipated.

Jan 1, 1986

By Ray W. Ballmer

Historically, Bingham is a rail pit, starting with steam locomotives in 1906 and converting to electric locomotives in 1923. Ore production was maintained through an effective utilization of available rail equipment. From time to time as it became necessary to deepen the pit and as stripping ratios increased, various studies were made on alternate material haulage systems. Utilization of diesel locomotives, conveyor belts, and trucks have all been subjects of study, however, conversion from rail haulage utilizing electric locomotives could not be justified. Because of the gradual decline in ore grade, a program was approved in 1963 to raise ore production to 108,000 tons per day. This was designed to return copper production to the 1950 level. Attainment of this production level by expansion of the rail system had definite limitations and built-in inflexibility. Track and trolley wire relocation causes shovel down time in excess of that required for normal maintenance. Instability of the dumps and the resulting additional track maintenance increases greatly as the volume of waste material to be handled daily expands.

Jan 1, 1965

By John T. Awald

The efficiency of search for porphyry copper and molybdenum deposits can be greatly increased. A model exploration system is here presented to show how geologic literature data and field surveys can be aided by modern statistical and computer methods. Assuming that major ore deposits occur in clusters, it is possible to evaluate rapidly large areas at modest cost and with minimum investment risk. An example of the success of these methods is given. Clusters of mine density and metal production covering the State of Nevada were plotted and machine contoured. Selection of a 47,300 square-mile area on the Nevada-California border was made. Within this area, detailed analyses were performed, and a 3000 square-mile site was picked for subsequent field examination. To initiate efficiently the field work, 81 stream sediment geochemical samples were collected and analyzed for copper, zinc, and molybdenum. These data established local variance and necessary statistical controls. Following this, a total of 151 geochemical samples were used to survey the 3000 square-mile area. Computer contouring of results directed attention to specific target areas for detailed geologic analysis, property acquisition and drilling. A total of 22 copper-zinc and molybdenum anomalies were identified. Four of these were recommended for further exploration. To date, two have been acquired and drilled and preliminary ore reserve and financial analysis have been made on one. The estimated cost and time for the regional exploration phases leading to these targets were thirty man-weeks and $16,000.

Jan 1, 1973

"The National Mining Hall of Fame and Museum (NMHFM) announced the 2018 National Mining Hall of Fame inductees. This year’s inductees, selected by the National Mining Hall of Fame’s Board of Governors, represent exploration, extraction, management, education and research and development in the U.S. mining industry. Their contributions have had significant and lasting impacts on the mineral and mining industry; these individuals were selected for being mavericks, thought leaders, researchers, educators, mentors, wealth builders and philanthropists.Professor John M. Guilbert, Dr. Leo J. Miller, Robert E. (Bob) Murray and Douglas (Doug) B. Silver will join 240 other mining industry luminaries when formally inducted into the National Mining Hall of Fame on Sept. 29, 2018. Additionally, the Prazen Living Legend of Mining Award will be presented to the Freeport- McMoRan Foundation. The 31st Annual Induction Banquet and Ceremony will be held at the Ritz-Carlton in Denver, CO.2018 National Mining Hall of Fame inducteesProfessor John M. Guilbert was a renowned geologist and professor of economic geology at the University of Arizona; he had a distinguished 50-plus year career in academia and business. Guilbert, together with J. David Lowell, worked on the most important breakthrough in mineral exploration in the last 100 years, the Porphyry Copper Model. This work, known as the Lowell and Guilbert Model, was utilized by exploration geologists worldwide over the next four decades to discover hundreds of millions of tons of copper metal and numerous profitable mines including the prosperous Bajo de la Alumbrera copper mine in Argentina. Guilbert was a founder of The World Museum of Mining in Butte, MT. He was the recipient of countless awards including the Society of Economic Geologists (SEG) R.A.F. Penrose Medal as well as the D.C. Jackling Award from the SME.Dr. Leo J. Miller was a maverick in the mining industry and no armchair geologist. He believed that active fieldwork, on foot with a rock pick, was indispensable for exploration. His basic tenet was to absorb as much information about an exploration target up front, formulate ideas – sometimes novel ones — and then get out into the field to prove those ideas. Miller was known to diverge from the standard interpretation of the geological processes, which formed the mineral deposits, and to apply innovative applications of high-tech tools to more usual exploration programs. This approach resulted in a 50-plus year career that included the discovery of the Kidd Creek massive sulfide deposit and the development of the Lee Creek phosphate deposit; which other explorers had previously given up on, believing whatever phosphate might be present would be too difficult and expensive to mine. The recipient of many honors and awards, Miller received the SME Robert M. Dreyer award in recognition of outstanding achievement in ore discoveries."

Jan 8, 2018

By Paul K. Edwards

The forces of nature have concentrated sand at various geographical locations that are being mined and processed for a large variety of industrial uses. While most operations serve a number of industries, this paper deals only with the foundry requirements. The forces that have decomposed a source rock, transported this material and redeposited it, have created two general types of sand. These types are classified as the (1) Lake and Bank Sands and (2) Silica Sands. The Lake and Bank sands will contain 92 to 94% Sio2 while silica sands are in excess of 98.5% Si02 and most of the producers wash these sands to up grade their products to 99.5% or better. Included in the Lake and Bank sand would be the river sands that are used primarily for construction purposes. The Foundry Industry is broken down into three types of castings : 1. Grey Iron Foundries The grey iron castings largest market is the automotive industry in Ohio, Northern Kentucky, Indiana, Illinois and Michigan. These castings are poured at temperatures ranging from 2400° to 2700°F. The Silica Sands or the Lake and Bank Sands will satisfy the requirements of the grey iron castings. There are 2 ½ to three million tons per year shipped from the state of Michigan far grey iron castings by the Lake and Bank Sand Producers.

Jan 1, 1974

By William Gleason

"Mining roots run deep in Glenrock, WY, a town that was founded in part, because of the coal mining that began in the late 1800s. But that rich history also now threatens large parts of the town that were built over the top of the mines. Like many towns in the Western United States, mining is a proud part of the historical fabric and heritage of the town, but the legacy issues from past mining activities continue to present challenges to modern-day engineers.In the case of Glenrock, a small town about 40 km (25 miles) east of Casper, it is flooding from a century of water that has accumulated in the down geologic dip of the furthest northeastern extent of 87 ha (217 acres) of mine workings that has made the town susceptible to sinkholes and other issues (Fig. 1).Full commercial coal mining production began in Glenrock in 1887 during the development of the Fremont, Elkhorn and Missouri Valley railway. Due to poor overlying roof rock and continuous flooding within Glenrock, Mines No. 1 and 2 were fully closed in 1909. During its history, an estimated 87 ha (217 acres) were mined with 50 to 60 percent extraction ratio within the eastern town limits through room-and-pillar mining. It is estimated that the mines produced 22 kt/a (25,000 stpy) during their lifetime. A century later, the water pressure built up in the northeastern most portion of the mine has created serious concerns for residents.In 2016, the Wyoming Department of Environmental Quality’s Abandoned Mine Lands Divisions (AML) investigated a number of subsidence events in the town including sinkholes following heavy precipitation. The AML investigations confirmed that most events were related to the previous mining in the area.Mitigation efforts on the mines were done in the 1980s and 1990s, but the problems in the town and in a nearby subdivision persisted, leading the AML to search for alternative solutions."

Nov 1, 2019

By Elizabeth Anne Semon

The marketability of a large volume bulk material is significantly effected by transportation costs. Hence, it is essential for anyone that deals with minerals or mineral wastes to be able to reliably estimate bulk transport costs. The three types of bulk overland transportation modes that will be discussed are truck, railroad, and pipeline. Contract and private carriage are the two types of truck transport generally suitable for movement of bulk commodities. Contract carriers are those transportation firms that service a limited number of shippers and geographic points, and carry a restricted number of commodities. Private carriage consists of control over drivers and equipment by the shipper, ownership or lease of the transport equipment, and shipment of commodities related to the primary business of the shipper.1 A combination of private and contract carriage may also be used. Depending on the size and regularity of the shipment, rail offers single car, multiple car, or unit train service to move bulk minerals. Both long and short distance pipeline transportation has been shown economically and technically feasible for many different solids such as, mine and quarry products, coal, chemicals, copper concentrates, phosphate rock, and sewage sludge. 2

Jan 1, 1973

By A. Moergeli, Philip Sander, John Reilly

"SUMMARY While the basic elements of risk management, including probability, consequences, risk registers, mitigation measures, etc., are now well understood, the process to include correlation, dependencies and linkage of risks and risk scenarios is less well defined and not well understood. To perform accurate and complete risk analysis and risk management, it is necessary to include correlation, dependencies and linkage between risk events, as well as risks that may occur multiple times. In this way, owners and contractors can more accurately determine risk-based costs, risk impacts and risk mitigation strategies. This paper will outline methods to deal with correlation, dependencies and linkage and will consider risks that may occur multiple times. Practical result comparisons – with or without these elements – will be presented. INTRODUCTION We believe the reader is familiar with basic concepts of risk, risk management and mitigation and the use of probabilistic cost-risk processes versus deterministic ones (Reilly et al. 2015; Sander et al. 2015). The probabilistic approach, compared to the simpler and more common deterministic approach (unit prices times unit costs plus a contingency), offers more useful information with respect to the range of probable cost as well as cost “drivers” and better quantifies the effects of risks, opportunities and variability – which improves understanding, leading to a better potential for profit (or loss) for contractors and added value for owners. In this context, a valid and sufficient quantification of correlation, dependencies and linkage of risk events, plus the impact of risks that may occur multiple times, is essential. Components of Cost Estimates – Base Cost, Risks and Other Uncertainties The components of cost that need to be correctly addressed in an estimate include (Moergeli et al. 2015): •,Base costs – the costs that will result if “all goes according to plan” (Reilly 2004) •,Risk costs – the resulting costs of threat and opportunity events, if they should occur •,Escalation costs – costs resulting from normally expected inflation with variability •,Other uncertain costs – costs that result from other events, normally external to the project team’s control, which may include unanticipated events, politically related changes and “black swan” events (Talib 2007)"

Jan 1, 2016

By K. K. Wu

In some cases, coal barrier pillars must be relied on to withstand high hydrostatic pressures in order to prevent inundation of active mine workings. Such barriers are particularly important in areas, such as parts of West Virginia, where much of the future mining is down dip of mines which have been abandoned, or are currently being worked. Also, where multiple seam mining is conducted, a barrier pillar in one mine may be critical to safety in a mine in a lower seam. MSHA's Coal Mine Safety and Health district offices and the Mine Waste and Geotechnical Engineering Branch of the Pittsburgh Technical Support Center, have recently been involved in the study of barrier pillars in Kentucky, Virginia, West Virginia, Ohio and Oklahoma. In this paper, the factors involved in determining the required width of pillar are discussed, past practices for sizing barriers are reviewed, and related current Federal regulations are examined. In addition, the results of laboratory testing of bottom rock are presented.

Jan 1, 1980

By J. Réal Cloutier

[Options are a natural extension of the forward and futures markets as they offer fexible method of hedging exposure. -An organized options market is preferable to the "over the counter forward markets since EGCC (EOE, ME, VSE) assumes responsibility for contract fulfillment minimizing credit risks by guaranteeing transactions. -Options ante considerably more "fexible" than the futures and forward markets, permitting prompt, precise and respected adjustment of one's exposure risk position. -The risk to the buyer of the options market is limited to the initial premium paid.]

Jan 1, 1983

By José Ricardo Lopes, Alaor Coelho, Marco Gomes, Alfredo Dacio Moraes Filho, Akira Koshima

"Very low strength alluvial peat soil was found under two old drainage galleries with just 4.3m cover above a twin tunnel due to be excavated by a 10.6m diameter EPB Shield for São Paulo Metro’s Line 5. Alignment was required to strengthen soil and drive the TBM through safely without damaging the galleries. The design included six levels of self-drilling forepoling with lengths up to 15m, using 100 mm-diameter SCH160 metal tubing and injection bulbs with estimated 0.20m diameter. Two 6m-diameter circular shafts were excavated along the shield-tunnel axis, one each side of the galleries, and forepoling fanned out under gallery foundations. Given the peculiar soil and confined working space, more data were needed for correct drilling geometry. Ground mass treatment was successfully designed and executed and galleries were fitted with instruments to enable the shield’s advance. DESCRIPTION São Paulo Metro’s Line 5 (aka Lilas or purple line) is adding 11 stations along an 11.5km extension and three EPB TBMs are being used simultaneously (three EPBs on the same job for the first time in Brazil) with one of them excavating a large cross- section twin-track tunnel. Currently the largest work-in-progress for São Paulo Metro, this project has been divided into seven lots and 9km are already operational. This study refers to Lot 6 where the 10.6m - diameter EPB shield excavation is only 4.3m below two galleries running through a 10m layer of very soft peat soil in an old alluvial riverside region ringed by major roads. After recent filling, this area (Parque das Bicicletas) was used for recreation, although temporarily it has become a construction site. This paper will describe the original basic design; precautions in relation to the structural condition of the galleries after inspection; the problem of absence of data for their foundations; subsoil bore tests; evolution of the engineering design for the galleries and conditioning and reinforcing the soft soil below the galleries to ensure safe advance of the EPB shield, and finally the successful outcome of the solution used."

Jan 1, 2016

By C. Roos, K. Jetmore

Developing a strategic underground mine plan is challenging and investigating multiple scenarios may take weeks. This process can be sped up using the Theory of Constraints to isolate the bottleneck mining activity and simplify the mine schedule process. This paper presents a technique to apply the Theory of Constraints to test multiple cutoff grade scenarios in Mineable Shape Optimiser and quickly produce many high-level production-based schedules that can be easily interpreted using stope-by-stope graphs, the Hill of Value, and through incremental return analysis.

Mar 2, 2022

By C. Basilio

Thermodynamic calculations based on a rigorous mass balance technique have been carried out for the chalcocite-potassium ethyl xanthate (KEX) system. The results of the calculations are used to: i) construct Eh-pH diagrams for KEX additions ranging from 0 to 10-4 M, ii) determine the amounts of cupric ions and copper xanthate formed at different Eh and pH values to make three-dimensional diagrams, and iii) determine the minimum KEX addition required to form CuX and CuX2.. This allows prediction of the optimum conditions for flotation and comparison of this with microflotation test data. In addition, voltammetry experiments have been conducted on chalcocite electrodes at pH 9.2 and pH 6.8 in order to gain information on the role of metastable species in flotation. On the basis of these experiments, possible reaction mechanisms are discussed and comparisons are made with what is expected on the basis of thermodynamics.

Jan 1, 1985

By W. R. Ernst

A method for the removal of nickel and vanadium contaminants from spent HDS catalysts involves pretreating the catalyst with H2S followed by the extraction of the metals with an acidic solution of ferric ion. The ferric ion solution alone removes significant amounts of active ingredients cobalt and molybdenum; however, after pretreating the catalyst with H2S, the extraction becomes more selective for the removal of Ni and V.

Jan 1, 1986

By C. H. Bucknam

Acid neutralization titrations were applied to the characterization of soil and overburden for the control and prediction of acid rock drainage in the coal fields of the eastern United States in the 1970?s (1). These became known as the Sobek methods as a result of the early United States Environmental Protection Agency publication and the methods have been modified (2) to be adapted to many applications in the metal mining sector (3,4,5,6,), and, as a result, there are a large number of acid neutralization potential methods being used that are referred to as Modified Sobek methods. Standardization of neutralization potential methods for metal bearing ores and related materials based on carbonate carbon, rather than titration, commenced in the 1990?s through the American Society of Methods and Materials (ASTM) Committee E01 on Analytical Chemistry for Metal Ores and Related Materials Subcommittee E01.02 on Ores, Concentrates and Related Metallurgical Materials (7). A subcommittee section, E01.02.05 on Environmental Methods, was organized to coordinate the method and material standardization efforts of ASTM and the Acid Drainage Technology Initiative Metal Mining Sector (ADTI-MMS) Prediction Committee (8), which took on the project of standardization of the acid neutralization potential acidity titration method (ANPA) to supplement the carbonate carbon method in E1915 (9) for application to samples which have metal carbonates (10), in particular, which result in overestimation of the neutralization potential using the carbonate carbon methods (11).

Jan 1, 2010

By D. D. Rabb

Originally, the term solution mining applied to a dissolution, washing, or "brining" of soluble salts such as halite (common table salt), potash or trona. After the mid-sixties, however, the definition has been expanded to include heap and dump leaching, in-place (in situ) leaching, removal of oil from tar sands, extraction of sulfur from deep wells by the Frasch process and the recovery of metalliferous solutions from geothermal sources. Solution mining is also known as borehole, non-shaft, or chemical mining; the extraction of soluble mineral values from a variety of ores using appropriate solvents and chemicals. Solution mining frequently involves chemical changes; for example, copper usually goes into solution as copper sulfate, gold and silver as a cyanide compound, and uranium as a sulfate or uranyl tricarbonate. The valuable constituent is removed from the solid body of the ore by mass transfer to a aqueous solution.

Jan 1, 1986

By Jaime Lomelin

[First of all I want to thank the Society of Mining Engineers of AIME for the opportunity to present what Industrias Penoles, S.A. is doing in Mexico to reach the basic objetive of the enterprise without compromising, in short or long term, the living conditions of the community or attempting in an irreversible form against Nature. Industrias Penoles, S.A. is one of the largest mining and metallurgical companies in Mexico. It was founded in 1887 and at the turn of the century installed a lead smelting operation close to the village of Torreon, which became city five years after the start up of the Penoles smelter. Now Torreon has a population close to 300,000 inhabitants. In 1974 Penoles is still the largest industry in Torreon and the dynamic growth of the city is close related to this factor. Today Penoles in Torreon has a lead smelter with a capacity of 130,000 metric tons/year of bullion, an electrolitic zinc plant of 105,000 metric ton/year, and it is modernizing its lead smelter to control pollution and expand it to 190,000 metric ton/year of bullion including all the services and refinery. The Penoles complex in Torreon is the biggest in the non-ferrous metals field in Latinoamérica.]

Jan 1, 1974