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By R. K. Mehta

Existing acid mine drainage treatment techniques are not remedial In nature, i.e. though heavy metals can be removed from acid mine water, their presence in tailings and large quantities of these tailings tend to increase capital and operating cost for tailing management. This paper presents the results of a series of systematic tests which finally resulted In the development of the "ferrite" process for mine drainage of coal operations at ambient temperature. The role of pH, temperature, quantity of ferrous salt addition and degree of oxidation is investigated targeting the production of high emu spinel ferrites and effluent water complying regulatory standards with respect to Iron. manganese suspended solids and pH.

Jan 1, 1992

By G. T. Lineberry, L. Adler

Due to safety-imposed constraints on clearances for mobile bulk handling equipment, it is necessary to optimally select a unit based on speed and size. The unit cannot be both large and fast. Since output is proportional to both size (or capacity) and speed, the combination must be carefully examined to maximize output. A simple graphical procedure and a calculus-based solution are presented to accomplish this. While the procedure applies to all mobile bulk handlers, as an example of the solution technique, attention is focused on shuttle cars. Background Major variables To fully define a bulk handling problem, the conditions, equipment, and activities must be characterized. The conditions and activities, when lumped together, are termed "encumbered space," since they "act to impede motion, as with a burden" (Lineberry, 1979). The insertion of mobile bulk handling equipment into what is already a difficult set of conditions and activities compounds the state of encumbrance, as limited space is competed for by many normal and life support systems. Long (1972) recognized the effects of design criteria, including road width, on haulage vehicle speed and, therefore, on production. Velocity -clearance curves Velocity-clearance curves are either available or can be constructed in the field. A preliminary set of curves for average conditions and activities is shown in Fig. 1, where clearances are only for the side of the vehicle (Lineberry and Adler, 1984). These curves set the safe speed limits for a vehicle operating at given clearances, under given conditions and activities. When feasible, velocity-clearance curves should be constructed through field measurement and observation. Curve construction should also consider haulway roughness, distances, and operator skill, as well as loading and dumping characteristics. It should be noted that haulage capacity determination is a total systems problem, not one just dependent on velocity and clearances. Production requirements and company capabilities also influence capacity determination.

Jan 10, 1985

By M. Ziegler

The article deals with the use of a digital twin in the assessment and optimization of a conveyor system in the Chilean copper mine. This example shows that a digital twin is initially just a new (albeit powerful) tool with which the system behavior can be examined. The benefits for the customer arise through the system identification and automatic detection of critical deviations from the target state. This knowledge allows mine management to react and coordinate operational and/or maintenance counter measures to insure optimal performance of their conveyor system. The information derived from the BeltGenius digital twin also allows mine management to gain a clear perspective of the overall efficiency of their conveyors, which will be invaluable for future conveyor component selections.

Mar 2, 2022

By J. W. Butwell

Anaconda has been active In the Bingham mining district near Tooele, Utah since 1914 when the company acquired International Smelting & Refining Co. Over the years both custom ores and complex Pb-Zn-Cu ores from the district were milled and smelted at International. In 1948 Anaconda acquired the property that covers the present Carr Fork ore body. Since that time active exploration took place in the 50's followed by detailed geological evaluation in the 60's. Convinced that high grade Cu deposits would be found at depth, a deep drilling program commenced in the late 60?s, with intersection of the ore zone in 1969. Following extensive deep drilling in the early 70?s, a feasibility study was conducted in 73-74 with board approval given Sept. 6, 1974. The 9,000 t/d mine-mill complex was budgeted at $217 MM over a 5 year schedule with start-up in Sept., 1979. The following discussion includes the concentrator and surface facility portion of the budget or approximately $60 MM of the scope. Special emphasis will be made on equipment selection and layout.

Jan 1, 1980

By D. A. Poulter

The stability of a liner system is influenced by many factors which can be compiled into four basic groups. They are: 1. the liner system components and physical characteristics; 2. the geometry and slope of the liner system; 3. the loading conditions on the liner system; and 4. the foundation conditions under the liner system. Failures in the liner system that are due to one or more factors from the first three groups usually result in movement relative to the plans of the liner system. Failures associated with factors in the fourth group result in deformation(s) across the liner system section beyond its design limits. For purposes of these discussions a failure in the liner system refers to displacements or movements resulting in physical damage to the liner system such that it can no longer function.

Jan 1, 1995

By T. C. Eisele

The separating efficiency of a flotation column is largely limited by the degree of backmixing of tailings into the froth zone, and its recovery is limited by the degree of short-circuiting of feed to the tailings. Current columns are typically made very tall, on the order of 30-40 feet, in order to limit the effects of backmixing and short-circuiting. These effects can also be reduced in a much shorter column, provided that the flow in the column approaches plug-flow. In this work, horizontal baffles were shown to improve the performance of a 6-foot tall laboratory-scale flotation column treating a difficult-to-clean, heavily oxidized coal. Tests with variation in the position of the baffles showed that for the greatest benefit, baffles are needed both above and below the feed inlet. Tracer tests with a fluorescent dye water tracer showed that the addition of the baffles reduced the amount of feed water entrained into the froth at any given coal recovery.

Jan 1, 1994

The National Mining Hall of Fame and Museum (NMHF&M) will induct the 2013 National Mining Hall of Fame class on Sept. 14, 2013. The ceremony will take place at the Brown Palace Hotel in Denver, CO. Representing the domestic and worldwide metal production, education, and health and safety sectors of the industry, this year?s five inductees cover a diverse cross-section of the mining industry. The inductees are: Charles F. Barber, Donald W. Gentry, Patrick H. O?Neill, Milton H. Ward and David A. Zegeer. They will join 218 other mining industry pioneers when they are formally inducted into the National Mining Hall of Fame at the 26th Annual Induction Banquet and Ceremony. They were selected for being visionaries, leaders and ambassadors, both within their own sectors and across the industry at large. Barber was a top executive at leading U.S. metals producer Asarco from 1956 to 1982. During his tenure, Asarco responded successfully to the demanding requirements of new environmental legislation in the United States and to changing concepts of foreign investment in mining, especially in Latin America. Gentry?s career took him from being a working mining engineer, to renowned mining educator, to president and chief executive officer of a mining company. As an educator, he had a positive impact upon hundreds, if not thousands, of new mining engineers and many others who took his short courses in mine economics. During his years in South America, O?Neill did everything from supervising operations of 15-bucket ladder gold dredges to becoming president of International Mining Corp. As an executive, he emphasized provision of education and training to local people working at mine sites for which he had responsibility. Ward?s experience covered the world and spectrum of metals, minerals and ores, ranging from A to Z (antimony to zinc and Australia to Zambia). He was president, chairman and chief executive officer of Cyprus Amax Minerals from 1992 to 1999, and he was president and chief operating officer of Freeport-McMoRan from 1983 to 1992, during which time he was instrumental in developing Freeport?s world-class Indonesian operations. Zegeer dedicated his mining career to protecting the health and safety of miners as a corporate executive, head of the U.S. Mine Safety and Health Administration (MSHA) and community leader. His tenure at MSHA coincided with a period of remarkable progress in U.S. mining safety .NMHF&M Board of Directors Chairman Paul C. Jones said: ?The five outstanding gentlemen being honored this year as inductees into the National Mining Hall of Fame are classic examples of the leadership and work ethic that has made America?s mining industry the world leader in technically sound, environmentally and socially correct, and economical mineral production that sets the standards for mining worldwide. We are very proud to add these five legendary gentlemen, who have demonstrated their sound technical and management skills to advance society on a worldwide basis, to our current list of 218 inductees being honored by the National Mining Hall of Fame.? 2013 Prazen Award winner ? The Nevada Mining Association is the recipient of the 2013 Prazen Living Legend of Mining Award

Aug 1, 2013

By D. G. Ball

Other than being used to convey fill material for the gob stowage or building of ribside packs on advancing longwell faces, pneumatic conveying has not been used for the transport of materials on a large scale in mining operations. The technique is extensively used in the wood products industry for conveying wood chips, limestone and other ingredients for the manufacture of paper, for the transfer from railcars, barges or ships to silos or stockpiles and further transfer into the pulp mills. This method of material transfer has the distinct advantage of transporting suitable material over horizontal and vertical distances within the same system. In considering material associated with mining, this includes, ore, coal and rock up to 4 inch cubed size, throughputs of 200 tons per hour over horizontal distances of 3000 feet or vertical lifts of 2000 feet. In recent years tests have been carried out to determine the physical and economic limitations of pneumatic hoisting, the results of which have led to the installation of two fully productive coal hoisting systems at mines of the National Coal Board in Great Britain. The equipment used for the pneumatic hoisting of coal or waste rock is described in this paper, together with a brief history of the tests which led up to the installation of the two hoisting systems in Great Britain.

Jan 1, 1977

By Klaus Rieker

"Since the mid-19th century the River Emscher in the German Ruhr District has been used for disposing of wastewater. In the early 1990s, it was decided to replace the existing open wastewater system with a sewer system and to restore the River Emscher to its natural state. The major Emscher conversion project is divided into a large number of individual schemes, with construction phase 30 being the largest. By applying the pipe jacking method, interlinking tunnels with section lengths in excess of 1,100 m are constructed. USAGE OF THE EMSCHER OVER TIME The 85-km long river Emscher flows right through the Ruhr District. It has its source to the east of Dortmund and flows into the river Rhine near Dinslaken (Figure 1).The Emscher has been used to dispose of wastewater since industrialization began about 200 years ago. Intensive coal mining over the years led to considerable subsidence causing stagnant sewer areas which in turn led to typhus and other deceases. Thus in 1899, the Emschergenossenschaft was founded to create an efficient interceptor system for a catchment area of 865 km² through lining, raising and Emschergenossenschaft decided to free the waterways of the Emscher system from sewage and to improve them in ecological terms by 2020. A budget of 4.5 billion euros was earmarked for this purpose.The construction of sewer conduits began in order to no longer transfer the wastewater into the Emscher. The currently ongoing construction of the “Emscher Interceptor” - the main sewer - represents the heart of the Emscher conversion project. The interceptor will run along the river over a length of 51 km. Three pumping stations are required to confine the sewer’s depth to elevations between 15 and a maximum of 40 m below the surface. Since early 2012, the Emscher has been free from wastewater east of the Dortmund-Deusen clarification plant. There are two further clarification plants situated along the Emscher, which treat the still contaminated river water down-stream. Once the Emscher Interceptor is in operation, they will receive wastewater solely from the tunnel system."

Jan 1, 2016

By S. D. Abbott

Mines are filled with a mixture of gases, some of which are toxic, flammable, or explosive. Others serve as early reporters of impending problems. Mines monitor these gases in order to ensure the safe, efficient operation of the facility and avoid losses or disasters. Two different approaches to monitor these gases have historically been taken. One kind of device measures the amount of each gas present by using selective detectors (e.g. handhelds and spectrometers). Another kind separates the mixture of gases into the individual constituents, then measures the amount of each gas present (e.g. gas chromatographs). Handheld units are the most widely used, but gas chromatographs are the most powerful yet underutilized units available to enhance mining operations. There are many misconceptions about the nature, applicability and proper use of each type of device, and little data is available. Up to this point, many people had only the manufacturers? claims to guide them. This study was undertaken to clarify the range of applicability, important characteristics, and value in use of these units in real-world situations. An additional goal of the study was to provide ways to evaluate comparative data, and thus aid mining operations in choosing the most beneficial and reasonable ways to use such devices in various situations and contexts.

Feb 23, 2014

By J. Grubb

"The undertakings described in the paper titled “Study on correlation of quantified coal rank with self-heating temperature” by Wang and Luo in the November 2015 issue of Mining Engineering (Wang and Luo, 2015) are mathematically sustainable and an acceptable extension of work performed by Smith and Lazzara (1987) for the U.S. Bureau of Mines. The paper is not an accurate explanation of the currently accepted leading practice for determining the propensity of a coal seam for spontaneous combustion. The paper could lead a practitioner to an oversimplified conclusion on how to determine the propensity of a coal seam to spontaneously combust.The spontaneous combustion of coal is a complex and not fully understood reaction. What is understood is that many more factors other than selfheating temperature (SHT) and coal rank are required to sufficiently evaluate the risk of spontaneous combustion in a particular coal seam. A superficial assessment can lead to an improper response to the risk. Some statements on the next steps through an appropriate literature search would have made the authors’ conclusions more credible.The SponCom 2.0 software, updated by the National Institute for Occupational Health and Safety (NIOSH) in 2011, provides a path for evaluating the susceptibility of a coal seam to spontaneous combustion. In addition to proximate and ultimate analyses to establish coal rank, and therefore an estimate of SHT, the program includes the history of heatings, friability, seam thickness, overburden thickness, rider seam presence, pyrite presence, face and butt cleat densities, geothermal source presence and other geological features in the assessment. Mining conditions including floor heave, rib sloughage and rate of advance are also assessed to conclude a propensity for spontaneous combustion."

Jun 1, 2016

By L. E. Eary

Many of the major international gold mining companies provide data on rates of greenhouse gas (GHG) emissions as part of their environmental reporting commitments. These data are evaluated by an index defined as the annual GHG emission rate in metric tons, divided by the annual amount of gold produced in grams, and referred to as GHGgold. This paper examines ranges of GHGgold values for a cross section of gold mines as a function of mining method (openpit, underground and combined operation) and ore-processing method (mill, heap leach and combined methods) for reported ranges of operational data, including annual total tons mined, ore processed and gold grade. The evaluation shows that ranges and distributions of rates of GHG emission are approximately similar across different mining methods and ore-processing methods. The data presented in this paper provide the context needed to make comparisons of GHG emissions reported in companies’ annual reports to the ranges reported for the overall gold mining industry.

Jan 1, 2009

By L. B. Gittinger

Mr, Chairman, members- and guests of the AIMS, I greatly appreciate this opportunity to speak before you. I hope this is just the beginning of a long and mutually beneficial relationship. This winter I decided to join the other 36 Freeporters who belong to the AIME; and, I applied for membership in the Society of Mining Engineers. To queries as to my interests in the Society, I had this answer: our principal challenge -- more so today, than at any time in my nearly 25 years in the industry -- is discovery and development of new sources of raw materials. I want to join you in meeting this challenge.

Jan 1, 1966

By E. Allen Hendt

It is a pleasure to be invited to speak before a gathering of executives representing America's leading mineral companies, I welcome this opportunity, particularly because it comes at an important period in the development of U.S. commodity policy. This morning, I discussed our general commodity policy primarily in the. Context of the north-south dialogue between developed and developing countries. This afternoon, I would like to focus more specifically on potential cartel activity and U.S. mineral import dependence.

Jan 1, 1978

By Stephanie Singarayer, Damodara Reddy Chinnasane, Mike Yao, Danielle Pelletier

Mining at Vale’s Creighton Mine has been active for nearly 120 years in Sudbury, Ontario, Canada. Being the deepest mine in the Sudbury region, mining induced seismicity is a common occurrence at Creighton Mine. Over the past five years, 26 large magnitude seismic events ranging from 2.5 Mn to 3.7 Mn (Nuttli) have occurred. Out of these large magnitude events, three 3.0+ Mn events occurred between April 2020 and January 2021. The majority of the 3.0+ Mn events are believed to be the fault-slip type that could be linked to the known major geological structures and/or long-term effect of mining over many years. The recent large magnitude events are believed to be triggered by high induced stresses while mining the first few stopes of a new lower horizon in the top-down centre out mining sequence.

Apr 26, 2022

By J. A. M. Cano

With a view toward increasing its product competitiveness in the foreign market, SAMARCO MINERACAO S/A has developed high MgO type pellets at its pilot plant for performing direct reduction simulation tests. Additives such as dolomitic lime and magnesite were used for increasing pellet MgO content. Comparative direct reduction simulation tests were conducted both in SAMARCO and foreign laboratories. The test results showed that it is possible to produce direct reduction type pellets with satisfactory metallurgical properties, which can be successfully processed at increased temperatures in direct reduction furnaces.

Jan 1, 1992

By Aliakbar Golshani, Behnam Eslami

"Surface settlement adjacent to sensitive structures is a challenging issue in the tunnel engineering. In this study, 3D simulation of TBM excavation has been performed with the FLAC3D code and then the results compared with real monitoring data. Sensitivity analysis was carried out for all parameters affecting the surface settlement, such as the tail void grouting pressure (Pt), the face pressure (Pf), the tunnel diameter (D), overburden (q), shield thickness (t) and the length of the shield (L). The results show that the face pressure, tail void grouting and tunnel diameter have a considerable effect on the maximum ground displacement.In this paper, the monitoring data from Mashhad Metro was used to verify the numerical simulation. Data monitoring for about 47 sections between A2 and D2 stations was selected and a multiple regression analysis was performed. Based on this analysis, an empirical relationship was obtained for the coefficient of regression relationship which confirmed the sensitivity analysis.INTRODUCTIONThe surface settlement due to tunnel excavation is a complex issue, since the surface displacement is a function of several parameters that they are related to the excavation method, soil characteristics and TBM elements. Prediction of deformation is a very important issue, especially in urban areas, since these displacements may be affected the superficial structures. In recent studies, one of the most popular empirical relationships that is used to predict the surface displacement has gussian curve that it was suggested by Peck [1, 2]. An analytical relationship was proposed by Chow that its base assume was isotropic of soil, that surface settlement can be estimated based on the tunnel geometry and the shear modulus(G) [3]. Besides these methods numerical approaches such as the Finite Element Method (FEM) and the Finite Difference Method (FDM) have been used over the last twenty years, since numerical modeling has a high capability to simulation a complex soil conditions and irregular geometry [4]. In this study, all aspects of the EPB-TBM on Mashad Metro Line 2 were modeled and the most important influences on surface displacement in urban areas were determined [1, 3]."

Jan 1, 2016

By H. E. Rojas

The primary objective of most comminution operations is liberation; however, mill performance is generally quantified in terms of particle size. Only recently has the use of image analysis equipment made it possible to quantify mill performance on the basis of liberation. In this investigation, a series of tests were carried out to study the effect of mill operating parameters on the liberation of sphalerite from a sphalerite/dolomite ore. The parameters studied included mill rotational speed, mill loading and ball size. The results of this work appear to indicate that sphalerite liberation is improved under conditions that promote impact breakage, while dolomite breakage is enhanced under attrition conditions.

Jan 1, 1990

By Gerry Norton

The purpose of this paper is to make the most complete assessment of coal cleaning methods, both process and equipment related to modern-day production and environmental requirements. In order to achieve this primary objective, a number of interdependent aspects of coal cleaning technology require evaluation and analysis. 1.0 CLASSIFICATION OF SEPARATION PROCESSES Processes and cleaning equipment can be categorized according to the important parameters of 1) mechanics of separation, 2) size range application, 3) range or variance in accuracy of separation related to 2) above, and 4) feed-size ratio affecting 3) above.

Jan 1, 1977

By I. H. Gundiler

A pilot-plant flotation concentrate containing 21.6 g/t gold and 2 kg/t silver was used for this study. Base-line cyanide and thiourea tests showed 30-40% extraction of both gold and silver. After roasting (450-750C), the maximum gold extracted was 89% with thiourea and 76% with cyanide. Pressure oxidation tests were conducted following a statistical experimental design in a 2L laboratory autoclave at 10% pulp density, and the residues were subsequently leached in acidic thiourea solutions for 2h. Leach results were presented in the form of contour maps, and optimum autoclave conditions were determined for maximum gold extraction (93%). However, silver extraction was only 7% when gold extraction was maximized.

Jan 1, 1992