Search Documents

P.T. Freeport Indonesia's latest expansion has increased total mill throughput to 125,000 dry metric tonnes per day. The most recent expansion included the installation of a Semi Autogenous Mill designed to treat more ore than any other single SAG mill currently operating in the world. Also included in the expansion were two large ball mills, rougher and cleaner flotation including conventional and column cells and a regrind circuit. All equipment is supported by a modem distributed control system. This paper describes the design considerations, construction, commissioning and start-up of the SAG concentrator and support facilities and includes an overview of the oreflow and milling facilities.

Jan 1, 1996

By John G. Groppo, James C. Hower, Cortland F. Eble, Rick Q. Honaker, Alireza Valian, Stephen F. Greb

Coal and coal combustion byproducts are potential candidates for alternative resources of REEs (rare earth elements). The Illinois Basin is a major coal-producing district in the USA, but little work is available on speciation of REEs in the basin’s coals. In this study, a total number of 382 samples from known locations in the Illinois Basin coal beds were acquired, analyzed for their REE contents, and investigated for any spatial trends or chemical correlations. This study includes Springfield, Herrin, and Baker coal beds—the most heavily mined coals in the basin. An average coal ash from the basin contains 320 ppm REE, with Baker being the highest (407 ppm on average). However, the distribution of REEs in the coal beds was laterally and vertically heterogeneous. A number of trends were found in the REE variations. The most important trend was the relationships of the REE concentrations and fractionations with the distance from the syndepositional sandstones. The total REE concentrations were higher in the proximity of the sandstones, likely due to the increased deposition of detrital material. This increase was the most significant in Springfield coal (90%) and least in Baker (6%). Those coal samples from the Springfield and Herrin coal beds distal from the syndepositional sandstones had a heavy to light REE ratio (H/L ratio) of 0.40 on average, whereas in proximal locations, the ratio was dropped to an average of 0.30. This trend was not significant in the Baker coal bed. In general, higher mineral matter in the coals was associated with higher REEs. In coal preparation plants, refuse rocks can have up to 360 ppmREE. However, the ashes of the cleanest coals had higher REE levels. Such ashes also have a higher ratio of heavy to light REEs. The highest REE concentrations were found in the claystones and the shales associated with the coal beds. Since the naturally occurring calcite, quartz, and pyrite samples were depleted in REEs, an association of REEs with the clay minerals can be suggested.

Jul 20, 2020

By Jack M. Campbell

The regulatory process by which governmental authorities acknowledge and, in turn, permit the location, construction, and operation of large scale energy-related facilities has become extremely detailed in recent years. One example of the detail that is entailed in the regulatory process is the number of permits that must be acquired by operators prior to the construction and operation of energy-related facilities. It has been estimated, for example, that 75 permits are required prior to the opening of a new coal mine in Pennsylvania while 50 are required in Kentucky. From the perspective of facility owners and operators the regulatory process often appears overly complex and may be perceived as a constraint to the corporate decision making process. From the perspective of those responsible for administering regulations, the process is perceived as a mans by which public desires - pursuant to social objectives such as environmental protection and occupational safety - can be achieved. As a result of conflicting organizational interests, the clash between energy facility owners and operators and their regulators appears to be inevitable. Furthermore, the resolution of this conflict lies in the tradeoff between objectives and the costs of regulation. The balance of objectives and costs is a subject of the political process and not a topic of consideration in this paper. This paper is concerned with the actual administration of regulations, that is, the implementation of that which arises from the interplay of organizational interests. The paper assumes that environmental control laws will not likely be repealed, that regulations to implement the intent of these laws are here to stay and thus the paper seeks to assess how regulations are administered at various levels of government pursuant to objectives. The paper hypothesizes that the administration of objectives (or policy) has an impact on decision making which affects energy facility decision; making while recognizing the fact that regulatory policy cannot be totally divorced from administration, this paper proceeds

Jan 1, 1977

By K. Kavouridis

The energy and climate protection policy of European Union (EU), and its Member States adopted in 2007 bridges security of supply, environmental protection and competitiveness. The objectives of the EU energy and environmental strategy cover the foreseeable period till 2020. It assumes all sources of energy will be needed. The objectives for renewable and improved efficiency are ambitious; it must be established if they are also realistic. Coal can continue to make valuable contribution to the security of supply and low price of electricity, only with technologies allowing for drastic reduction of the CO2 emitted of its combustion. The aimed at -20% reduction of green-house gases (GHG) of EU-27 by 2020 is an objective limited in time and content. Europe produces less than 15% of global CO2 and this will be reduced to 10% in 2030. Emissions Trading (ET) is to remain the central instrument for CO2 management, especially in the power sector. ET scheme (ETS) or other mechanisms need designing to create an incentive for investment in higher efficiency and technologies and to Carbon Capture & Storage (CCS). The ETS as the climate protection instrument of the EU can become a heavy burden (high fuel and electricity prices, less security of supply) or it can create a climate for modernization of fossil fuel power plants. The suggestion in this paper of fuel-specific benchmark system for CO2 allocation after 2012 can combine the emission levels to be reached with a strong drive to invest, the necessary investment security, transparency and the principle of proportionality. A Benchmark System as recommended by coal industry could adapt to the different circumstances in the long term and comply with EU energy and environmental policy objectives.

Jan 1, 2008

By G. A. Munoz

Gold leaching of an auriferous pyrite ore from the Portovelo deposit in Ecuador indicates that noncyanide leaching systems, such as thiocyanate and thiourea, are not as effective as the traditional cyanide system. For example, whereas approximately 95% of the gold can be leached from the ore with cyanide, only about 50% gold dissolution can be achieved with a thiocyanate leaching system. Electrochemical measurements indicate that gold is not cathodically protected by pyrite in these systems. Based on the results of preliminary diagnostic experiments, it appears that gold dissolution in thiocyanate and thiourea systems is limited by passivation due to the formation of either elemental sulfur or sulfur compounds on the gold surface.

Jan 1, 1999

By W. G. Pariseau

"BACKGROUND Strata mechanics of three underground coal mines in central Utah were recently studied using a specialized finite element technique [1, 2, 3, 4]. The purpose of these studies was to examine relationships between mining and related seismicity. The longwall mining method was predominant, but room and pillar mining and barrier pillar mining were also used in the mines studied. In every case, high correlation between face advance and seismicity was observed. The specialized finite element technique allows for whole mine subsidence estimation at a kilometer scale and for stress concentration at a meter scale near a working face. Comparisons of observed mine subsidence with model subsidence allows for model verification and justifies detailed analysis of the evolution of stress at seam level. Yielding is expected near a longwall panel face and as the face is advanced the extent of yielding is expected to increase. The total number of element failures in a finite element mine model also increases, so a high correlation with associated seismicity, say, event count, is not so surprising. A brief review of recent coal mine studies in Utah is presented in the sequel. The procedures are given in some detail in application to trona mining. COAL MINES The analysis procedure begins with the geologic column and proceeds to specification of strata properties including elastic moduli and strengths. Joints are an integral part of the geologic model and joint set specifications include dip direction, dip, spacing, stiffness and strength. Spatial variability of strata properties in situ may be taken into account during analysis. Topography is important, especially to Utah coal mines that are developed from outcrop in regions of high relief. Mesh generation follows specification of data input. Finite element analysis is next, followed by reporting of results. In this regard, all finite element computations are based on first principles. No model “calibration” is done that involves adjusting computer input to obtain a fit to mine measurements such as subsidence profiles. Figure 1 illustrates the concept of a dual node – dual mesh finite element concept. Dual nodes are roof and floor nodes in mined areas. These nodes replace the seam. The dual mesh is a much refined mesh with displacement boundary conditions obtained from the big mesh and thus replaces the effect of mining in the region outside the dual mesh. The refined dual mesh allows for details of stress, strain and displacement near a working face of interest. Strata Properties Strata properties include elastic moduli and strengths of intact rock between joints and joint stiffness and strength for each joint set present. Both properties sets may be obtained from laboratory test data, although testing joints poses a sampling problem in the field. The statistical variability observed in laboratory test data, say, in unconfined compressive strength tests is often characterized by much variation. In fact, the coefficient of variation, ratio of standard deviation to mean, is often greater than 35 percent. When sample values are mapped back to the mine location, one may observe spatial variability as properties vary from place to place as shown in Figure 2. Spatial variability may be incorporated into a finite element analysis with probabilistic assignment of properties to elements in accordance with measured variability. The result is a more realistic model of rock in situ."

Jan 1, 2017

By George Schmitt, Ted Dowey, Grant Millener, Sean McAndrew, Eric Jordan

The Rondout-West Branch Bypass Tunnel is being built to bypass a substantial leak in New York City’s primary water supply tunnel. The 13,500 foot long tunnel travels 600 feet under the Hudson River through the same troubled geology and high pressure water inflows that the original tunnel did in the 1940s. A Robbins TBM traversed this geology and built gasketed segments. Nine thousand two hundred feet of 16 foot diameter interliner was installed and backfilled within the segments. Finally, reinforced cast in place lining was placed. This paper addresses the challenges and the multi-tasking approach the contractor utilized.

Jun 13, 2021

By Andrew Cho, Changsoo (Kevin) Moon, Richard Flanagan, Brian Larsen

"INTRODUCTION Project Background The U.S. Army Corps of Engineers (USACE)/Port Authority of New York & New Jersey (PANYNJ), as part of their New York and New Jersey Harbor Deepening Project, will dredge this shipping channel to a depth of 16.5 m below mean low water (MLW). By deepening the channel, the new generation of larger, “post-panamax” container ships coming to U.S. waters as a result of the expansion of Panama Canal can be accommodated in local marine terminals, helping to retain the nearly 300,000 jobs and $12 billion in annual wages the PANYNJ provides to the region. The existing siphons are situated at a depth that could be compromised by the planned dredging of the channel (nycedc.com). The purpose of this project is to build a new 1.83 m diameter water main inside a 3.66m diameter tunnel replacing the two existing siphons in order to provide the necessary backup water supply to Staten Island across the Anchorage Channel within the Upper New York Bay from Brooklyn. The proposed tunnel is approximately 2.9 km long and at a depth of at least 26 m below MLW. The project is funded jointly by New York City’s Department of Environmental Protection (NYCDEP) and PANYNJ and is managed by New York City Economic Development Corporation (NYCEDC). The contractor of the project is Tully/OHL JV, the designer is CDM/HMM JV, and the CM is LiRo/PB JV. History of New York City’s Soft Ground Tunneling The New York City area has a relatively long history of soft ground tunneling, commencing in the late 19th century. Construction of the first Hudson River tunnel crossings was begun (but not completed) in 1874 for the Hudson & Manhattan Railroad using compressed air supplying a shield. The work continued intermittently until the project finally opened for service in 1907. These 1.72km long tunnels (maximum depths of 29 m) are still in operation and now operated as the PATH Tunnels. They are approximately 5.5m diameter utilizing cast iron segments. The river bed consisted of primarily silt with shallow rock near the New York side. Air “leaks” occurred during the compressed air excavations resulting in some serious “blows” with water and soil entering the tunnel, including one incident with 20 deaths."

Jan 1, 2016

PolyMet Mining is developing the NorthMet property near Duluth, MN. Laboratory investigations have led to the development of the Platsol process to dissolve in one step the base metals (copper and nickel) as well as the gold and platinum group metals (PGM). To complete the prefeasibility study, a fully integrated, 10-day pilot plant trial was undertaken. The trial consisted of high-temperature (>220ºC or >428ºF) pressure oxidation in the presence of 5 to 10 g/L chloride (the Platsol process). This was followed by solid/liquid separation, gold plus PGM recovery from solution, conventional copper solvent extractions/electrowinning (SX/EW) and recycling of the copper raffinate to the autoclave. The concentrate tested during the trial period was a NorthMet bulk flotation concentrate. It assayed 14.7% Cu, 3.05% Ni, 0.14% Co, 26.7% S, 1.4 g/t (0.041 oz/st) Au, 2.2 g/t (0.064 oz/st) Pt and 9.9 g/t (0.289 oz/st) Pd Laboratory results were confirmed and, with minor adjustments of the laboratory Platsol conditions, the following leach extractions were obtained during the pilot plant trial: 99.6% Cu, 98.9% Ni, 96% Co, 94.6% Pd, 96 % Pt and 89.4 % Au.

Jan 1, 2003

By W. W. Dudley

The U.S. Geological Survey, in support of underground testing of nuclear explosives, has developed a technique (Dudley, 1910) to predict the inflow of ground water to large underground chambers that are cylindrical in shape. By treating the chamber as a large-diameter well pumped at constant drawdown, the nonsteady discharge can be computed by the method of Hantush (1961) for analyzing flowing wells under leaky artesian conditions. In mining applications, whether for mineral recovery or for nuclear testing, the most serious departure from the conditions of Hantush's model results from the gradual enlargement of the opening under drained conditions. Inherent in the analytical technique is that the "well" is fully completed at the time that dewatering begins. Because safety is the prime concern, however, initial pumping systems or personnel evacuation procedures must be designed to handle the greatest conceivable inflow. DEFINITIONS Because somewhat different meanings are attached to similar words in different technical fields, the U.S. Geological Survey definitions (Lohman, 1970) of several hydrologic terms used in this report are given below. An aquifer is a formation, group of formations, or part of a formation that contains sufficient saturated permeable material to yield significant quantities of water to wells, and springs. A confining bed is a body of material lying stratigraphically adjacent to one or more aquifers and having a hydraulic conductivity distinctly lower than that of the aquifer. The total head (dimensions L) of a liquid at a given point is the sum of three components: (1) elevation head, he, which is equal to the elevation of the point above a datum; (2) pressure head, hp, which is the height of a column of static water that can be supported by the static pressure at the point; and (3) velocity head, hv, which is the height the kinetic energy of the liquid is

Jan 1, 1971

By Richard M. Winar

In September of 1988, the United States Environmental Protection Agency (US EPA) published final regulations that effect owners and operators of underground storage tanks (USTs). These regulation include stringent technical requirements for owners and operators of USTs containing petroleum and certain hazardous substances. The technical requirements effect both new (those installed after December 1988) and existing USTs and include notification; performance and operating standards; release detection, reporting, investigation; release response and corrective action; and closure requirements for out-of-service USTs. The USEPA also published final regulations regarding financial responsibility requirements for owners or operators of petroleum USTs in October of 1988. These regulations require owners or operators of petroleum USTs to demonstrate financial responsibility for the costs of corrective action and compensating third parties for bodily injury or property damage caused by releases from petroleum USTs. Like thousands of other industries, the mining industry must become thoroughly familiar with these new regulations in order to properly manage their UST systems, ensure compliance, and understand other ramifications imposed by these regulations.

Jan 1, 1990

By Andrew J. Petruska, Rik Banerjee

This study explores implementing a machine learningbased system to generate a 3D surface repre- sentation of the roof and support straps in the mine. Event cameras have been chosen for their performance in high-dynamic-range lighting conditions and for their low latency. To enable automated drilling and bolting, 3D vision using eventbased cameras has been developed. A ground-truth set is created using two, time-synced event cameras and a LiDAR camera. These sensors are used to construct a ground-truth dataset of corresponding event- camera images and surface maps from the LiDAR. The network is tested with stereopairs of event images and produces a depth image with ±5 mm RMS error on average across 1000 test images.

Feb 1, 2024

By Fred C. Bond

The perennial subject of comminution is deserving of a fresh approach if one can be found. This is attempted here by directing attention primarily to principles rather than to theories. While theories attempt to explain how a certain process acts, principles delineate the laws which the action-must follow. Comminution may be defined as the progressive separation of particulate matter. At the present time this is accomplished commercially by applying energy in the form of compressive and, shearing forces. Such forces strain and distort the particles they contact. When-the applied stress locally exceeds the breaking strength at the weakest flaw in the particle, a crack tip forms. The surrounding strain energy flows to the crack tip, which rapidly extends through the particle as a break. The minute changes in shape and the resulting energy flow cause the failure of other highly stressed flaws, with the consequent formation of a progeny (1) of new smaller particles out of its destroyed progenitor. The applied mechanical energy is transformed into strain energy as the particle is distorted, and then into heat when it fails. Only a tiny fraction of the order of 1/1000 of the applied energy necessary for breakage appears as new surface energy in the product particles. The comminution problem is the relationship between, energy input and product particle size. Its solution is of great-economic importance,

Jan 1, 1961

For nearly two decades, MINExpo International has held the title to the biggest show in mining. The 2012 MINExpo is expected to be the biggest yet, with nearly 1,800 exhibitors rolling out the newest equipment and services across 12 halls. From September 24 to 26 in the Las Vegas Convention Center, MINExpo will present the newest in everything from automation and robotics to safety and communications equipment to reclamation services, and much, much more. The last MINExpo, in 2008, had nearly 38,500 visitors. The show?s sponsor, the National Mining Association, expects this year will be even bigger, with more than 40,000 visitors over three days. Twenty talks on the issues facing mining today are scheduled for Tuesday and Wednesday mornings, but the real action will happen out on the floor. That?s where ultra haul trucks big enough to carry as much as 363 t (400 st) of rock will be assembled next to underground loaders able to lift more than 20 t (22 st) in one scoop. Caterpillar, Komatsu, Liebherr, Sandvik, Atlas Copco: all the big names in mining equipment will be there. Their massive earthmoving equipment and mining machines are the centerpiece of the show. Preassembly for the largest pieces begins on August 6, 2012.

Jan 1, 2013

By Emily Wortman-Wunder

As the 2009 president of the Society for Mining, Metallurgy, and Exploration, Inc., I am pleased to present the 2009 issue of Transactions of the Society for Mining, Metallurgy, and Exploration, Vol. 326. A significant portion of the contribution that we as a society make is the publication of professional and technical papers that contribute to the advancement of scientific knowledge and information transfer. Communication within the mining community is the key to a successful society. Through the information-transfer mechanisms of books, magazines, meetings and electronic media, the technology exchange that is fundamental to the existence of the Society is accomplished. This technology exchange continues a tradition that dates back to the 1871 meeting of 22 mining engineers in Wilkes-Barre, Pennsylvania, that resulted in the founding of AIME; those individuals envisioned that these transaction volumes “would form a most valuable and greatly needed addition to our professional literature.” This volume certainly satisfies that intent. In keeping with SME’s tradition of promoting technological developments while honoring the past, the 2009 Transactions represents an important milestone. It is the last Transactions to appear as a bound volume. Future volumes will appear as e-books only, with some of the Transactions-only papers appearing online prior to the ebook (exactly what form the new Transactions will take is still in development). The decision to go to an all-digital format for this longstanding publication was a difficult one, but one which we hope will better serve the mining community, especially our international members. This 2009 Transactions of SME, Vol. 326, contains a total of 73 technical papers (510 pages), including all 23 papers (136 pages) that were published in 2009 in the Technical Papers Section of Mining Engineering magazine (Vol. 61) and all 32 papers (232 pages) that were published in 2009 in Minerals & Metallurgical Processing (Vol. 26). In addition, this volume contains 18 papers (142 pages) that are being published for the first time in this issue. The papers presented in this volume were written by some of the most distinguished professionals in the industry worldwide. All 73 technical papers were peer-reviewed and approved. The process of review and publication requires much hard work by authors, reviewers and publications staff. As the 2009 president of SME and on behalf of our members, I would like to extend our gratitude to all whose efforts contributed to the publication of this volume.

Jan 1, 2009

By Akram Marseet, Andrew J. Petruska, Rik Banerjee

Underground mine roof bolting is a crucial operation for miners’ safety and mine sustainability. Since roof bolting is a manual or human-supervised operation, miners’ safety is at risk due to dust or rock falls. Traditional machine learning algorithms have shown limitations to detecting drillable areas, mainly due to harsh lighting conditions. The authors propose an adaptive deep-learning framework for autonomous roof bolting. The proposed framework is based on implementing a binary semantic segmentation algorithm on color images to classify pixels that belong to rock from those that belong to non-rock. Significantly, the proposed framework implements deep learning semantic segmentation on images from traditional and neuromorphic vision sensors in underground mines. The performance of the proposed model shows an impressive accuracy level of at least 98% at a low number of training epochs with smooth learning curves. The high accuracy enables the implementation of autonomous roof bolting, greatly improving miners’ safety and operational efficiency while reducing human exposure to safety hazards. This research will advance the use of deep learning in mining automation and has the potential to revolutionize the traditional mining industry.

Feb 1, 2024

By Jean-Michel Rendu

That you are giving the Daniel C. Jackling award to me is a great personal honor. But more significantly, it is a recognition that geostatistics has come of age. And since I am considered by many as belonging to an older generation of geostatisticians, I thought that it would be fitting that I reflect on where geostatistics came from and where it might be going. First, though, let me propose a definition of geostatistics. Etymologically, paraphrasing Webster's definitions of "geo" and "statistics," it is "a branch of mathematics dealing with the collection, analysis, interpretation and presentation of masses of numerical data taken from the earth." This definition is most appropriate in the context of mining geostatistics. It includes both classical and spatial statistics. It emphasizes the earth aspect, or the analysis of geologic features. And it should remind the practitioner that geologic input is a critical part of all geostatistical applications. In the 1910s, statistical methods were already used to analyze geological data. However, the origin of geostatistics, as we know it today, is best set in the late 1940s, when H.S. Sichel recognized the lognormal distribution of sample values in the South African gold mines. In 1951, Daniel Krige observed that "it can be expected that the gold values in a whole mine will be subject to a larger relative variation than those in a portion of the mine." In other words, samples taken close to each other are more likely to have similar values than if taken farther apart. This observation is the foundation on which spatial statistics, which characterizes values defined in a multidimensional space, is built. However, the 1950s were marked by studies based on classical, as opposed to spatial, statistics. It was only in the 1960s that the need was recognized to model the similarity between sample values as a function of the distance between samples and that the semivariogram was defined. A theoretical framework was developed by Matheron that supplied an elegant mathematical explanation to the empirical observations made by Krige. Matheron coined the term "kriging" in recognition of Krige's pioneering work on the geostatistical evaluation of mineral deposits. As soon as this theoretical framework was developed, it was possible to bring geostatistics to the academic world. The "Centre de Geostatistiques" was founded in Fontainebleau. Numerous students were trained there, disciples eager not only to improve the theory and develop more sophisticated mathematical tools, but also to spread the new faith throughout the world. Expansion of geostatistics exploded in the 1970s, arguably the most fertile decade if it is judged by the frequency of theoretical breakthroughs, the number of original publica-

Jan 1, 1995

By Steve Kral

Through advanced technology and innovative thinking, the mining industry has become one of the world’s leading industries in environmental protection. But it only takes one Summitville, Omai or, most recently, the Aurul gold tailings retreatment operation in Romania to provide ammunition to the industry’s critics in their attempts to sway public opinion against mining. So for the mining industry to continue operating with the public’s support, it must continue to improve its tailings waste-disposal processes and the dams that hold this waste. In January, about 120 specialists in the mine waste management field gathered together to discuss the available technologies and materials for controlling mine waste and mill tailings disposal. “Tailings and Mine Waste’00” was held at Colorado State University in Fort Collins, CO. This meeting, begun in 1978, is a continuing symposium. It provides a forum for environmental professionals to discuss the state-of-the-art in mill tailings and mine-waste disposal methods.

Jan 1, 2000

By W. Collingwood

As openpit mines continue to grow deeper and productivity continues to increase, the management of respirable dust and noxious gases can become a challenge. The natural wind flow in openpit mines is often recirculatory. This recirculation traps dust and gases in deep openpit mines. This problem is particularly acute in high-latitude openpit mines, due to a phenomenon known as atmospheric inversion. In the winter, arctic and subarctic regions experience short days and long nights. This deficit of solar radiation creates a situation in which cold, still air accumulates near the bottom of the pit. In openpit mines, this can result in unhealthy accumulations of gases and other contaminants. In this study, the natural wind flow patterns in and around openpit mines were investigated using a computational fluid dynamics (CfD) program. Two-dimensional models were created for a variety of pit geometries. The effect of depth, slope angle and wind speed on the recirculation pattern in the pit was examined.

Jan 1, 2012

By Jerry Dolph

In September 1855, 55-year-old Noah Spencer Kellogg and his $3 jackass named Bill discovered what was known at the time as a “blow out” of high-grade lead and silver ore. The deposit was located on the side of a North Idaho mountain high above the South Fork of the Coeur d’Alene River. The ore was later assayed at 41,141 g/t (1,200 oz/st) silver. Kellogg named his discovery the Bunker Hill Lode, after the June 17, 1775 Revolutionary War battle of Bunker Hill. A thriving pioneer settlement sprang into existence around the resulting mine’s workings and was eventually— and appropriately — named Kellogg. The peak rising hundreds of feet above the mine’s adit was named “Jack-ass Peak” after Noah Kellogg’s hairy companion.

Jan 1, 1996