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By Michael Gauna, Christopher Mark

"For decades, pillar recovery accounted for a quarter of all roof fall fatalities in underground coal mines. Studies showed that a miner on a pillar recovery section was at least three times more likely to be killed by a roof fall than other coal miners. Since 2007, however, there has been just one fatal roof fall on a pillar line. This paper describes the process that resulted in this historic achievement. It covers both the key research findings and the ways in which those insights, beginning in the early 2000s, were implemented in mining practice.One key finding was that safe pillar recovery requires both global and local stability. Global stability is addressed primarily through proper pillar design, and became a major focus after the 2007 Crandall Canyon mine disaster. But the most significant improvements resulted from detailed studies that showed that local stability, defined as roof control in the immediate work area, could be achieved with three interventions:• Leaving an engineered final stump, rather than extracting the entire pillar;• Enhancing roof bolt support, particularly in intersections, and• Increasing the use of Mobile Roof Supports (MRS)A final component was an emphasis on better management of pillar recovery operations. This included a focus on worker positioning, as well as on the pillar and lift sequences, MRS operations, and hazard identification. As retreat mines have incorporated these elements into their Roof Control Plans, it has become clear that pillar recovery is not ""inherently unsafe.""The paper concludes with a discussion of the challenges that remain, including the problems of rib falls and coal bursts.INTRODUCTIONPillar recovery has always been an integral part of underground coal mining in the US. When room-and-pillar methods are employed, large blocks of coal in the form of pillars are initially left in place to support the weight of the overburden. Unless these pillars are subsequently recovered, the coal they contain will never be mined."

Jan 1, 2016

By Kenneth H. Johnston

This report describes an in situ combustion project and three waterflood projects in Allen, Anderson, and Wilson Counties, Kansas, that will be visited during the 1964 annual tour of the Kansas-Oklahoma Waterflood Association. Among the unique features of the projects are the movement of heavy crude oil through the reservoir and into the wellbore with energy furnished by burning s portion of the crude oil therein. Another feature is the simultaneous injection of C02 and water, through separate tubing into input wells during early development, to increase injectivity at moderate pressures, Discussion of individual projects includes information on their early history, source and treatment of injection fluids, oil production-decline curves, and the results of water injection on oil production.

Jan 1, 1964

Gold mines produce unique water treatment requirements. This paper focuses on case studies of innovative processes used for treatment of water resulting from gold mining and processing. The case studies include treatment of mine dewatering water for beneficial application from an Australian gold mine, Bendigo Mining, as well as treatment for arsenic removal of tailings water from mining and processing at Goldcorp mines in Canada. Gold mining can often require dewatering to prevent groundwater seeping into and flooding the mine workings. Gold mining and processing often accumulate wastewaters in a tailings dam. The mine water can contain contaminants such as dissolved salts, iron, arsenic, manganese, heavy metals and odorous sulfates. Environmental discharge requirements as well as community needs for water drive mine operators to consider the most appropriate water treatment process. Treatment of gold mine water can require processes including oxidation, pH adjustment, coagulation, flocculation, clarification, further oxidation/adsorption of specific metals such as manganese, filtration, salt reduction utilising reverse osmosis, brine minimisation and other innovative technologies. These processes are discussed through the case studies with examination of the specific treatment process that is required. This paper uses real case studies of gold water treatment processes to explain and examine the technology and the reasons for designing specific processes. The focus is toward explaining innovative processes where the water is used for sustainable environmental discharge or treatment to a quality that can be beneficially used by the local community.

Jan 1, 2007

By Cliff McCartney, Michael A. Trevits

The National Institute for Occupational Safety and Health (NIOSH) is conducting a program of research to evaluate and improve remote mine seal construction technology for mine fire control and suppression. The main focus of this work is to develop reliable technology that will remotely seal a mine opening from floor-to-roof and rib-to-rib. NIOSH, in partnership with Strata Mine Services Inc.1, is evaluating the capability of a two-component phenolic foam-based product, called Rocsil®1, that is intended for cavity filling, air and gas sealing, and consolidation of highly fractured strata. Rocsil® can be rapidly applied, has a quick cure time, a high expansion rate, good compressive resistance and excellent anti-static properties. When the resin and catalyst are mixed, an immediate foaming reaction occurs followed by rapid expansion up to 30 times the original volume. By virtue of its fire-resistance properties, Rocsil® foam has application for sealing underground mine areas undergoing heating from spontaneous combustion and it could be useful for remote mine seal construction to aid in mine fire control and suppression. This paper presents an overview of remote mine sealing technology, introduces the use of Rocsil® foam for remote mine seal installations, offers a case study of the use of this rigid foam material to remotely construct a temporary in-mine seal and discusses technology improvements. Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the views of NIOSH.

By J. Lindenau

One of the significant benefits of electronic detonators is their safety, especially their relative insensitivity to extraneous electrical energy. The various brands of electronic detonators on the market have different resistance to electrical stimuli, but all have safety structures designed to afford a significant level of protection. A common source of extraneous electrical energy is lightning. This paper discusses the nature of the energy that occurs with a lightning strike and the resistance offered by electronic detonators. Four actual cases of exposure of electronic detonators to lightning strikes are considered. Electronic detonators, like other initiation systems, are vulnerable to very close or direct lightning strikes. The incidents are a reminder that all blast patterns need to be vacated on the approach and during the progress of a lightning storm. 1. Orica

Jan 1, 2008

By C. Velásquez, W. Bergholz, C. Spence, P. Lind

NuevaUnión SpA (NuevaUnión) is a development project located in the Huasco province of the Atacama region of Chile. It is held in a joint venture company owned 50:50 by Teck Resources Limited (Teck) and Newmont Goldcorp. It includes the Cu-Mo Relincho deposit and the Cu-Au La Fortuna deposit, with plans to utilise a single concentrator to be built at the Relincho site. The Relincho site is at an altitude of 2,000 masl and is 40 km from the La Fortuna site which is at an altitude of 4,100 masl. The project is currently completing a Feasibility Study and is reviewing equipment selection and flowsheet options. This paper is based on the current thinking, and design decisions will be finalized at the completion of the Feasibility Study. NuevaUnión is currently planning for phased operation, processing Relincho ore at 104 ktpd followed by processing ore from La Fortuna at 116 ktpd. Plans for the third phase include doubling the main processing lines and returning to Relincho ore at a processing rate of 208 ktpd. The NuevaUnión concentrator will incorporate comminution and flotation circuits that are being designed to maximize the overall economic value of the combined ore deposits. Major ore characteristics differ between the two ore bodies, such as ore competency, grindability, liberation grind size, pulp rheology, tailings properties, minerals and metals of value, as well as gangue mineralogy. Mineral processing choices have been made to optimise value from each deposit and the combined project. INTRODUCTION Between 2010 and 2013, two significant mining projects were being developed in Chile: Goldcorp’s El Morro project had recently finalized a Feasibility Study and, in 2011, had received its environmental approval for construction; and Teck Resources Limited’s (Teck) Relincho project was finalizing a Feasibility Study and preparing its Environmental Impact Study. Both projects were: Geographically close, at only 40 km apart. Considering similar infrastructure. Each was planning to have its own concentrator, tailings management facility, high voltage power line, port, concentrate transport system, seawater desalination plant and pumping system to mine site.

Jan 1, 2019

By Peter Radziszewski

"Typical mining operating costs can be divided between extraction (30 % to 70 %), comminution (30 % to 50 %) and separation (5% to 20% ). Cornminition process costs, representing an important contribution to mining operating costs, can themselves be divided roughly between energy (50 %) and linerkharge wear (50 %). Developing the ability of predicting mill wear will allow a more accurate estimation of wear costs. However, total media wear in a given ball mill grinding process is a product of three recognized wear mechanisms those being abrasion, corrosion and impact. Further, the contribution to total media wear of each of these wear mechanisms has not been well established. In this paper, a overview of abrasive, corrosive and impact wear mechanisms is made from which an empirical wear prediction procedure is proposed. Further, future directions in wear prediction research is outlined. INTRODUCTIONTypical mining operating costs can be divided between extraction (30 % to 70 %), comminution (30 % to 50 %) and separation (5 % to 20 %). Comminition process costs, representing an important contribution to mining operating costs, can themselves be divided roughly between energy (50 %) and lined-charge wear (50 %). With respect to wear, world wide steel consumption as grinding media is estimated at over 600 000 tomes per annum (Malghan, 1982). As such, developing the ability of predicting mill wear will allow a more accurate estimation of wear costs.Charge media wear prediction is actually estimated using the Bond abrasion test. From Bond abrasion index tests, it is possible to determine a wear rate using the following function:"

Jan 1, 2000

By Manuel Caro

El presente trabajo describe el proceso de mantenimiento del equipo de aire denominado Optiair. Este filtro al tener una mayor capacidad de retención de polvo, permite que el equipo pueda trabajar por periodos más largos sin tener que detenerse para realizar el cambio de filtros, lo cual incrementa el factor de disponibilidad del equipo. Entre los beneficios principales tenemos: el incremento de salida de aire, menor restricción del flujo, menor caída de presión y una mayor cantidad de contaminante capturado.

Aug 25, 2002

Jan 1, 1987

By Jose A. Delgadillo

The hydrocyclone problem has been a challenging task for the last 30 years. In the 80’s and 90’s Computational Fluid Dynamics solution to this problem began to appear. These were unsuccessful due to over simplification. In the past 3 dimensional solution with ?-e model and Reynolds Stress Model have been published. In this paper RSM and ?-e models are compared with velocity profiles measured in 75 mm and 250 mm diameter hydrocyclones. It is shown that results are not satisfactory with RSM or ?-e and that a model called Large Eddy Simulation is needed to describe velocity profile evolution and size classification.

Jan 1, 2005

By D. A. Jacobson

Mining operations, whether new or existing, are constantly looking for ways to maximize production and improve energy efficiency, while keeping the footprint required to a minimum. The Nordberg MP1250 cone crusher was designed with these three goals in mind. A series of side-by-side evaluations comparing an MP1250 to an MP1000 were completed at two Freeport-McMoRan operations. The first evaluation began October 2009 in a tertiary position and the second began March 2010 in a secondary position, where it remains in full production today. Utilizing 25% higher power capacity than the existing MP1000 tertiary crushers, the MP1250 had 29% higher capacity and 17% lower specific energy, adjusted for differences in feed and product size. The MP1250 compared to the existing MP1000 secondary crushers achieved 30% higher capacity at a slightly reduced specific energy, while achieving a finer product. The MP1250?s higher capacity and energy efficiency may have application in many crushing plants. Depending on site specific economic factors, greenfield projects may benefit from a smaller footprint and less ancillary equipment, whereas brownfield projects may benefit from higher capacity or a finer product within the same footprint.

Jan 1, 2012

Gravity-driven rock falls account for a large proportion of all fatalities and injuries in underground mines. Potentially unstable blocks of rock are found in the hanging wall of excavations, which may be delineated by natural joints or stress fractures. These blocks, referred to as keyblocks, will fail if their weight exceeds the support capacity or if they are located between support units. This paper describes a computer program which simulates blocks in the hanging wall of an excavation based on measured properties of fractures and joints. Keyblocks are identified and placed at random locations in a predefined excavation. The keyblocks are tested against the support to determine whether they fail the support, drop out between the support or are stable. By repeating the procedure several thousand times, statistics of the probability of failure of the keyblocks are obtained. This approach allows the relative hazard associated with different types of support or excavation orientations to be obtained. It is concluded that a probabilistic approach is suitable for the evaluation of supports effectiveness in situations where large numbers of discontinuities or stress fractures are exposed in excavations.

Jan 1, 1998

By F. Terblanche, M. Holton, A. Kruger

The paper presents an optimal mine planning system designed to simultaneously optimize all the underground mines of large South African gold and platinum mining corporations. The system, code named PlanIT-OPTIM, is a multi-stage solution involving the use of adetailed 3D CAD-based mine planning system (CADSmine™V4). The mine design and scheduling rules defined in CADSmine™ are responsible for simulating mining sequencing, rock mechanics, and ventilation, etcetera. Feasible production ranges generated by CADSmine™ and various high-level mathematical models are used as inputs to a mathematical optimization engine. The optimization engine produces optimal production profiles (i.e. key business indicators such as tonnages, mineral and areas extracted per time period) by maximizing net present value. Other objectives such as profit continuity, production continuity and maintaining available reserves can also be specified as optimization criteria. The final step in the PlanIT-OPTIM process is to convert the optimal production profiles into practical and attainable business plans. This is achieved through the CADSmine™ Detail Optimization Engine that modifies the original CADSmine™ schedule to match the optimal production profiles. With current methods it is an impossible task to find the best business plan for a mining corporation in any reasonable period of time should conditions change (e.g. gold prices, exchangerates, grade estimates, etcetera). The fast turn around time achieved through PlanIT-OPTIM makes it possible to do several ‘what-if’ scenarios in a reasonably short time. PlanIT-OPTIM has already been used in the gold mining industry to find optimal business plans for a mine.

Jan 1, 2003

By Richard C. Moore

The U.S. Bureau of Mines contracted a study to review the air and water monitoring requirements of five Federal environmental acts (the Federal Water Pollution Control Act, the Safe Drinking Water Act, the Clean Air Act, the Surface Mining Control and Reclamation Act, and the Resource Conservation and Recovery Act) and to compile information on the currently available monitoring instruments. A literature review of the acts and their associated regulations was conducted to determine applicability to the mining industry as well as any air and water monitoring requirements. In addition, an industry search and literature review was performed to assess the instrumentation available to comply with the monitoring regulations. Based on this research, the instruments are classified by general applicability to air, surface water, or ground water monitoring, then catalogued by monitoring parameters. A discussion is provided on recommended and innovative monitoring techniques.

Jan 1, 1981

By Cosmin Carpinisan, Erich J. Hofmann, Stephen J. Hall

"Since presenting a technical paper regarding their unique capabilities in Forged Steel Mill Gearing at the SAG-2006 Conference, Australian heavy engineering company Hofmann Engineering has pioneered a number of new manufacturing processes and design concepts for components of large comminution equipment. These include: 1. Novel design improvements for HPGR Rolls with forged steel tyres and a unique patented tungsten carbide insert designed to improve wear life, enhance autogenous layer build-up, and to reduce breakage & chipping under load. 2. Development of forged fabricated Mill Heads using rolled & welded high-tensile steel plate as alternatives to cast conical mill heads. 3. Insitu Girth Gear measurements for profile and wear via portable 6-axis CMM. 4. Gear and Pinion designs to AGMA-6114 for SAG mills of 38’-40’ diameter to 24MW and for Ball Mills of 26’ diameter to 18MW. The paper presents case studies from the Australian heavy manufacturing facilities of Hofmann Engineering, combined with news of their new gear manufacturing and gearbox overhaul facility in Canada."

Jan 1, 2012

By Daniel Mageau

Ground freezing has been used for over 100 years to provide shoring and ground water cutoffs for hundreds of projects worldwide, including drilled shafts, tunnels and cofferdams. Typically, these cases involved difficult soil/water problems where ground freezing was likely the only solution. This paper discusses a recent ground freezing project where a frozen soil wall was used for a more conventional problem. A 4-foot-thick frozen soil wall was used to provide shoring and groundwater cutoff for a 20-foot-deep excavation during construction of a cast-in-place concrete storm water detention vault. The site is located along the northbound on-ramp to I405 from westbound SR522 in Woodinville, Washington. The frozen soil wall was successfully formed in soils consisting of till fill over soft organic silt and loose saturated sand in about 3 weeks. The depth to ground water varied from about 4 to 8 feet over the site. The unfrozen soil inside the frozen soil wall was excavated vertically to the frozen soil boundary. The vertical excavation remained open for approximately 2 months with no dewatering required. On one side, fully-loaded dump trucks and other construction equipment operated within 6 feet of the wall face with zero wall movement. This paper addresses the construction issues related to installation and operation of ground freezing shoring. The overall wall performance of the frozen soil wall as well as basic geotechnical design issues are also discussed.

Jan 1, 1998

By Yves Gratton

The International Commission on Large Dams (ICOLD) is a non-governmental International Organization which provides a forum for the exchange of knowledge and experience in dam engineering. It is the world's leading professional organization dedicated to advancing the technology of dam engineering and supporting socially and environmentally responsible development and management of the world's water resources. ICOLD was founded in 1928 and has National Committees in 82 countries with approximately 7,000 individual members who are engineers, geologists and scientists from governmental and private organizations, consulting firms universities, laboratories and construction companies. Its original aim was to encourage progession in planning, design, construction, operation and maintenance of large dams and associated civil works by collecting and disseminating relevant information and by studying related technical questions. Since the late sixties, focus was put on subjects of current concern such as dam safety, monitoring of performance, reanalysis of older dams and spillways, effects of ageing and environmental impacts. More recently, additional subjects have included cost studies at the planning and construction stages, harnessing international rivers, information for the public at large, and financing.

May 1, 2002

By T. Marin, J. E. Seccatore, M. Cardu

The most energy-intensive process in the mining industry is particle size reduction – comminution. The first phase of this process is blasting to fragment the rock from the initial Boussinesq’s halfspace size. Scientific literature demonstrates that the output of a blast in terms of fragment size distribution can be manipulated by varying the specific charge (powder factor) and charge distribution. This study focuses on the influence of blasting on the internal resistance of the blasted fragments; in particular the influence of the spatial distribution of charges. Small-scale blasts were performed on 14 marble blocks using different powder factors and charge distributions. Three control blocks were fragmented by mechanical means for comparison. The results show the correlations between charge distributions and the specific energy of mechanical comminution. Opportunities for adjusting charge diameter and distribution in opencast blasts to improve the performancet of comminution circuits are discussed.

Aug 8, 2024

By N. Sahin, K. Baris, A. Ozarslan

This paper aims to assess the current and future role of coal in energy strategy of Turkey and evaluates the compatibility of the policies to the EU energy policy and strategy. The Turkish government set targets to utilize more coal reserves of the country in next decades. However, the country is also in the process of becoming an EU Member State, hence, it is expected that the energy policies have to comply with the EU. Moreover, Turkey ratified Kyoto Protocol, thus the country should limit greenhouse gas emissions. Clean Coal, Carbon Capture and Storage (CCS) technologies are expected to become an important instrument for the mid-term reduction of CO2 emissions from coal-fired power plants. An alternative technique to the conventional CCS methods is CO2 sequestration by mineral carbonation. Turkey has significant resources of magnesium silicate minerals (olivine, serpentine) deposits which can be utilised in CO2 sequestration by mineral carbonation method.

Jan 1, 2011

By Robert A. Elgin

The Leadville mining-district (fig. 1) covers approximately 8 square miles adjacent to Leadville, the county seat of Lake County, Colo. It is famous for its large production of rich ores containing zinc, lead, copper, gold, and silver. Some manganiferous ores also have been produced.

Jan 1, 1949