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In 1991, Placer Dome Venezuela established a 70% stake in Minera Las Cristinas, to mine the Las Cristinas gold deposits in Bolivar. This case study examines the multi-sectoral partnership arrangement that was developed to improve health services near the proposed Las Cristinas gold mine. The investment climate in Venezuela is uncertain and the socio-economic circumstances are potentially hostile. Despite that, the partnership between the mining company, local communities, government agencies and an international health nongovernmental organization (NGO) collectively leveraged nearly $2.5 million to build and operate a community health center.

Jan 1, 2002

By J. Evans

Including: Tailings thickeners, CCD?s, paste thickeners, HI-rate thickeners, lamella thickeners, high compression thickeners, clarifiers etc. Flocculant dosing control for mining thickeners and clarifiers is influenced by a number of process factors. 1. Flow rate into the thickener or clarifier a) As the flow rate increases into the thickener or clarifier ?retention time? decreases which causes a greater affect hydraulically on the settling solids. So as the flow rate increases it will generally mean an increase in flocculant dosing rate. b) As the flow rate decreases into the thickener or clarifier the retention time increases which reduces the hydraulic affect on settling, improving settling rates. This will generally mean that as the flow rate decreases, we will decrease the flocculant dose rate.

Jan 1, 2011

By D. Babich, L. Alcorn, E. Spencer, A. Smith

Noise is one of the most pervasive health hazards in mining. A compilation of Mine Safety and Health Administration (MSHA) noise survey data for Fiscal year 1990 shows that approximately 40% of the total samples taken for longwall occupations exceeded the Permissible Exposure Limit (PEL) of 100% [Gigliotti et al. 1991]. In order to properly determine workers’ exposures on longwall coal mining systems, it is necessary to provide accurate baseline measurements for these mining systems. This research was designed to develop guidelines and test procedures for identifying all noise sources that are major contributors to the underground noise exposure of longwall coal mining system workers. Once the high noise sources are identified, promising engineering controls can be tested and evaluated to reduce the noise of the sources. The measurement system used to analyze the noise sources included stationary dosimeters in a documented repeatable pattern and a time-motion study of the cutting cycle and operator’s work cycle. Significant results from the underground measurements show that the highest sound levels recorded are at the stageloader discharge segment and tailpiece controls and remained at about the same level throughout the test.

Jan 1, 2007

By G. Tiess, S. Mujiyanto

Indonesia is a fast growing democratic developing country comprising more than 17,000 islands, founding member of ASEAN and a member of the G-20 major economies. It is one of the most highly mineralised countries in the world, the mining sector playing a pivotal role in the country's economy. In 2001, the Decentralization Law No. 22/1999 came into force and caused a transfer of authority and responsibility from central to regional and local administrative governments. The new Mining Law of 2009 substituted its 40 year old predecessor, but lacked detailed regulations for its implementation. These were only issued in 2010, which lead to a period of great uncertainty for investors in the mining industry. The new legislation intends to foster domestic economic development, which may be interpreted as protectionist policy. For the development of a sustainable mineral resources policy, further endeavours will have to be made.

Jan 1, 2011

By Y. Wang, E. Forssberg, A. Johansson, B. Chan

A super-conducting high gradient magnetic separator with matrix vibration in dry separation mode is a powder purification device, which has been used to remove weakly magnetic impure particles from fine calcite powders below 53 µm in this study. A fundamental question concerned is the evolution of the matrix clogging under gas-solids loads. This paper presents the improvement of the separation selectivity using a method of mechanically based vibration on the matrix in the separator. The functions of the matrix vibration are discussed. The results indicated that the mechanically based vibration on the matrix within a high intensity magnetic field while a feed was introduced in an air stream, was found to be effective for the dry purification of fine powder materials.

Jan 1, 2001

By W. G. Pariseau

Equivalent elastic properties of discontinuously jointed rock masses are computed using a non-representative volume element(NRVE) approach within a three dimensional finite element program. Joint persistence, defined as the percentage of a joint plane that is actually occupied by joint material, is used in the NRVE computations as a step towards greater realism in stability analysis of mine openings. Persistence p is also the probability that a segment of a joint plane is occupied by joint material. Computations reveal a threshold phenomenon in jointed rock mass moduli similar to that observed in percolation theory. A rapid decrease in moduli occurs above a critical value pc(about 0.6). A detailed analysis of the well-known solution for stress about a circular opening in isotropic, elastic ground illustrates the effects of joint set orientation, spacing and persistence. Although stable “on average”, joint segment failures reveal a threat to stability and point towards rational design of reinforcement or support of discontinuously jointed rock masses.

Jan 1, 2003

By S. Frimpong

Cable shovels are used for primary excavation in in-situ and/or pre-fragmented formations in surface mining operations. Poorly fragmented hard rock formations and random occurrence of hard boulders in soft formations cause extreme variability of material diggability, resulting in varying shovel stress loading. The stress loading of a shovel’s front-end assembly could result in fatigue failure. Conventional design process, which uses physical shovel simulation studies, is very costly and time consuming for achieving statistically significant results. In this paper, rigid and flexible multi-body dynamic theories are used to develop component stress loading and deformation models of the cable shovel, and solved in the ADAMS/NASTRAN/FLEX environments. Detailed simulation experiments are carried out to examine the performance, reliability, durability and efficiency of the P&H 4100A under varying in-situ formation conditions. The results show areas of high stress fields with a maximum stress of 313.31 MPa at node 441 within the hoist rope. The reliability of the results is confirmed by comparing existing test data. The study is significant because it provides a solid foundation for further study of failure life analysis of the cable shovel components.

Jan 1, 2007

By Joel Lööw, Jan Johansson, Lena Abrahamsson

Industry 4.0 offers new possibilities to combine increased productivity with stimulating workplaces in a good work environment. Used correctly, digitalization can create attractive jobs in safe control room environments, which provide space for the employee’s full expertise and creativity. This is true also for the mining industry. But, to succeed, it is important to analyze the development from a worker’s perspective. What will happen to their work? What skills will be needed in the mine of tomorrow? We must also consider the risks, such as privacy issues, increased stress, and work-life boundaries. These questions must be understood if we are to create workplaces that can attract a young and diverse workforce to tomorrow’s mining industry. In this article, we try to illustrate what the new technology can mean for the individual miners. We formulate the notion of Mining 4.0 (Industry 4.0 in the mining industry), where we try to create an image of how the future might look from a miner’s perspective and how mining companies may navigate their way to a future that works for all miners. To illustrate the range of possible outcomes, we formulate two scenarios: one utopian and one dystopic. At the end of our article, we bring forward six recommendations that can be considered a beginning of a road map for the human side of Mining 4.0.

By Joel Lööw, Jan Johansson, Lena Abrahamsson

Industry 4.0 offers new possibilities to combine increased productivity with stimulating workplaces in a good work environment. Used correctly, digitalization can create attractive jobs in safe control room environments, which provide space for the employee’s full expertise and creativity. This is true also for the mining industry. But, to succeed, it is important to analyze the development from a worker’s perspective. What will happen to their work? What skills will be needed in the mine of tomorrow? We must also consider the risks, such as privacy issues, increased stress, and work-life boundaries. These questions must be understood if we are to create workplaces that can attract a young and diverse workforce to tomorrow’s mining industry. In this article, we try to illustrate what the new technology can mean for the individual miners. We formulate the notion of Mining 4.0 (Industry 4.0 in the mining industry), where we try to create an image of how the future might look from a miner’s perspective and how mining companies may navigate their way to a future that works for all miners. To illustrate the range of possible outcomes, we formulate two scenarios: one utopian and one dystopic. At the end of our article, we bring forward six recommendations that can be considered a beginning of a road map for the human side of Mining 4.0.

By Kenneth N. Han, Peter Nam-soo Kim

A kinetic model for leaching of particulate metals in a batch system has been developed. The leaching mechanism has been analyzed by solving a series of ordinary differential equations relating heterogeneous reaction kinetics at the solid/liquid interface to mass transfer of reactant and products. Special emphasis has been given to the effect of changing of the surface area of the leaching substrate and initial particle distribution on the overall leaching rate. The dissolution of gold powders in acidic solution with bromine as an oxidant has been used as a model system. The effect of particle size, chemical reaction order, rate constant and mass transfer coefficient on the overall rate of dissolution of metal powder has been analyzed and discussed.

Jan 1, 2005

By R. S. Jurani

Sunshine Mining Co.'s Kellogg operation is the primary silver producer in the US. Maintaining a comfortable working environment in this deep underground mine historically has been a complex and costly problem. To improve the ventilation and cooling systems at a time of declining and un-certain silver markets, it was proposed to optimize the performance of existing facilities at minimum cost. This paper discusses a two-year, $400,000 optimization program that resulted in increased total mine airflow, cooler ambient temperatures, reduced compressed air usage, and lower energy consumption by primary fans, air compressors, and refrigeration plants. This saved the company about $650,000 per year.

Jan 1, 1988

By Brian Fulcher

The Arrowhead Tunnels Project represents the final portion of a 70 km (44-mile) long water conveyance facility that will bring up to 28 m3/sec (1,000 ft 3/sec) of water into Southern California. The 13 km (8-mile) tunnelling project is well underway and consists of two, 5.8 m (19-ft) diameter TBM bores through extremely variable geological conditions. An extensive and essential pre-excavation drilling and grouting program was performed in all reaches of the Arrowhead Tunnels Project, located north of San Bernardino, CA. This program supported the advance of two hybrid hard rock TBMs though extremely challenging ground conditions under substantial ground cover and up to 27 bar (900 ft) of ground water pressure. The well known San Andreas Fault lies nearby and has greatly influenced the local geological conditions. This paper will describe the means, methods and materials used throughout the numerous phases of the pre-excavation grouting program. It will also describe many versatile, flexible and innovative drilling and grouting methods and equipment systems utilized to improve performance, save time and costs in constantly changing geological conditions. Considerable lessons learned have been learned while overcoming some extremely formidable ground conditions and safely advancing the tunnels.

Jan 1, 2008

By Steve Wiig

In 1987, the Rock Springs, WY district office of the US Bureau of Land Management (BLM) began to develop an automated system to store, maintain and manipulate more than 14,000 drill hole logs contained in the district's office files for various solid leasable minerals. The development of this system was based predominantly on a trial-and-error basis, with many procedural changes incorporated over time. The current Automated Drill Hole Database and Analysis System will continue to evolve with new software developments and increased personal expertise in this field. The mission of the BLM's Branch of Solid Minerals is mandated by a series of federal laws. The most important are The Mineral Leasing Act, the Federal Land Policy and Management Act, the Federal Coal Lease Amendments Act and the Surface Mining Control and Reclamation Act. Several regulations, promulgated from these laws, dictate that BLM must perform certain tasks and functions as part of its specific duties. The regulations that apply to the BLM Solid Minerals program are codified at 43 Code of Federal Regulations (CFR) 3400 for coal, and at 43 CFR 3500 for non-energy solid leasable minerals, such as sodium, phosphate and potash. Specific functions required of the Branch of Solid Minerals necessitates the use of geologic and drill hole data analyses. These functions can be divided into pre-lease and post-lease. Examples of pre-lease functions that normally require some level of drill hole data analyses include:

Jan 1, 1992

By M. Gouet-Kaplan, J. A. Finch, S. Gélinas

Methylisobutyl carbinol (MIBC) and methoxy polypropylene glycol (Dowfroth 250) bubble thin films were characterized by composition and thickness determinations, using FT-IR spectroscopy and UV-Visible spectrophotometry, respectively. The infrared investigation indicates that the role of frother molecules in creating bubble thin films is based on their effectiveness in inducing H-bonding reorganization of the surrounding free water molecules into a coherent network. From UV-Visible interference patterns, it is found that MIBC forms films with a measured critical end thickness of less than 160 nm, compared to 612 ± 30 nm for Dowfroth 250. The observed values of the free water layer thickness are comparable at 5.65 ± 0.28 µm for MIBC and 6.75 ± 0.34 µm for Dowfroth 250. A higher stability of an MIBC bubble over a Dowfroth 250 bubble is related to the different polarization and orientation of the molecules sustaining the boundary surface water network. The findings are used to explain the different action and associated froth characteristics of the two common industrial frothing agents.

Jan 1, 2006

By H. J. Haselhuhn

Selective flocculation and dispersion processes for the concentration of hematite ore are strongly dependent on the ionic content of the process water. It has been noticed that magnesium ions are more detrimental to iron recoveries during desliming and flotation processes than calcium. This phenomenon was studied by measuring the zeta potential of hematite ore at various concentrations of magnesium, calcium, strontium and barium at a pH of 11. Results show that zeta potential inverts from negative to positive at very low concentrations of magnesium ions in the solution. It takes a significantly higher concentration of calcium, ions to achieve the same effect. This difference may be attributed to the ability of magnesium ions to adsorb to all surface hydroxyl groups, whereas calcium, due to their larger size, can only adsorb to every other hydroxyl group. This hypothesis was confirmed by results similar to those seen with calcium when this test was repeated with strontium and barium ions. The tendency for calcium ions to adsorb to every other surface hydroxyl group causes higher concentrations of calcium to be less detrimental to hematite concentration processes than magnesium.

Feb 27, 2013

By Norbert T. Rogers

An accepted statement of fact is that, next to agriculture, transportation is the second most important industry in the world. The transportation networks of the United States have greatly contributed to our nation's growth and prosperity. The objective here is to make the reader aware of the need for communication between geologists, mining engineers, purchasing agents, and transportation managers. Only through a cooperative effort is it possible to reap the benefits of transportation in the industrial minerals field. Transportation is often thought of in terms of trucks, rail cars, barges, and covered wagons. There is much more. Corning Inc. Corning Glass Works is a worldwide organization with more than $2 billion in annual sales. It supplies more than 60,000 different products a year to some 47,000 customer firms and millions of individual consumers. Corning operates 32 of its own plants worldwide and is also an investor with a 50-50 or minority position in 24 affiliated companies in 11 countries. Corning competes in four broad business categories: • specialty glass and ceramics; • consumer housewares; • laboratory sciences; and • telecommunications Binding these four sectors together is the glue of technology. Coming's research laboratory, established in 1908, was one of the first in American industry. That early commitment to research has never wavered. Today, Corning spends annually on research and devel¬opment, as a percentage of sales, at double the average rate for all manufacturing industry in the US. Some 1500 scientists, engineers, and support personnel are now employed at the company's research and development centers in the US, Japan, and France. Petalite background A family of materials melted conventionally as a glass, then converted by special processing to a ceramic was invented in 1957. One of the basic minerals in this glass ceramic product is petalite. Petalite is a monoclinic mineral with a framework silicate structure and a low iron content, about 0.06% Fe2O3. Petalite is found in very few places throughout the world and no commercial petalite deposit has been found in the United States. Sizable deposits occur in Zimbabwe, Southwest Africa, Brazil, Australia, the Soviet Union, and Sweden. Coming's purchasing and geology departments located a source of petalite with proven reserves in what was then known as Rhodesia. The supplier was Bikita Minerals. The relationship with Bikita was one in which Bikita supplied bulk ore that Corning processed into a finished material at its US facility. This bulk ore method of shipment resulted in high losses through contamination and processing. It also caused tank upsets at the Corning plant because of iron contamination picked up through the numerous handlings of this product in bulk. The relationship with Bikita continued until 1965 when the white political leadership of Rhodesia declared its independence from Great Britain. This led to the imposition of international sanctions. The sanctions were lifted in 1980 and the relationship with Bikita was reestablished in 1983.

Jan 1, 1989

By Z. A. Md-Nor

Risk management is an established loss-control methodology that has been applied successfully in many industries. Recently, interest in this structured approach has grown in the mining industry. The main objective of this research was to develop a risk-assessment process, which is a part of risk management, that can be used by the U.S. mining industry to more thoroughly characterize risks associated with haul truck-related fatalities. The assessment is based on historical data obtained from the U.S. Mine Safety and Health Administration (MSHA) investigation reports, which includes 113 fatal incidents that occurred from 1995 through 2006. The risk-assessment process used in this research involves the following basic steps: identification of the risks, risk analysis and risk evaluation. The preliminary hazard assessment (PHA) method is used in identifying and quantifying risks. Risk levels are then developed using a pre-established risk matrix that ranks them according to probability and severity. The resulting assigned risk value can then be used to prioritize control strategies. This paper is a part of a detailed study on risk assessment for equipment-related fatalities in mining sponsored by the Western U.S. Mining Safety and Health Training and Translation Center.

Jan 1, 2008

By Justyna Swolkień, Nikodem Szlązak, Dariusz Obracaj

Polish coal mines are characterized by severe geological conditions and the co-occurrence of natural hazards. These hazards are associated with methane and dust emissions during mining processes which can provide methane, dust or methane-dust explosions. Besides, there are such natural hazards as gas and rock outbursts, rock bursts, spontaneous combustion of coal and environmental heat load. The mutual influences of various geological conditions, as well as the natural hazards, intensify the increase of the methane explosion hazard. The occurrence of methane explosions in the Polish mining industry between 2013 and 2108 are analyzed. Fatal accidents are compared with similar events in the global mining industry. The methods of preventing the explosion hazard as well as methane emission control in the Polish coal mining sector are presented. Methane hazard prevention should be adapted to levels and other natural hazards, especially those related to ventilation of underground mine. The methods of preventing methane emissions into mine excavations are often contrary to the means of preventing other ventilation-related hazards in the underground mine, e.g. the prevention of spontaneous combustion of coal in the goaf of longwall panel. Therefore, the design of longwall panels should be preceded by a detailed analysis of the results of both methane emission prediction and forecast of other ventilation-related hazards.

By Justyna Swolkień, Nikodem Szlązak, Dariusz Obracaj

Polish coal mines are characterized by severe geological conditions and the co-occurrence of natural hazards. These hazards are associated with methane and dust emissions during mining processes which can provide methane, dust or methane-dust explosions. Besides, there are such natural hazards as gas and rock outbursts, rock bursts, spontaneous combustion of coal and environmental heat load. The mutual influences of various geological conditions, as well as the natural hazards, intensify the increase of the methane explosion hazard. The occurrence of methane explosions in the Polish mining industry between 2013 and 2108 are analyzed. Fatal accidents are compared with similar events in the global mining industry. The methods of preventing the explosion hazard as well as methane emission control in the Polish coal mining sector are presented. Methane hazard prevention should be adapted to levels and other natural hazards, especially those related to ventilation of underground mine. The methods of preventing methane emissions into mine excavations are often contrary to the means of preventing other ventilation-related hazards in the underground mine, e.g. the prevention of spontaneous combustion of coal in the goaf of longwall panel. Therefore, the design of longwall panels should be preceded by a detailed analysis of the results of both methane emission prediction and forecast of other ventilation-related hazards.

By W. J. Nokleberg, B. A. Bouley, T. K. Bundtzen

Central Alaska contains a wide variety of pre-, syn-, and post -accretionary mineral deposits that are related to the growth and evolution of the north-west North American continental margin. Withinpre-accretionary terranes, the Devonian-Carboniferous, carbonate platform-hosted MVT zinc-lead deposits of the Kandik and Reef Ridge districts in central Alaska, and the Devonian-Mississippian volcanogenic massive sulfide (VMS) polymetallic deposits of the Bonnifield, and Delta mineral belts of eastern Interior Alaska have received the most exploration interest to date. Syn-accretionary rift related, mafic and ultramafic sill swarms and zoned plutons of the Kluane-Nikolai igneous belt are currently being explored for Ni-Cu-Co-PGE deposits. Syn-accretionary granitoid complexes in the PurcellMountains, Illinois Creek, and Sitylemenkat areas have been explored for uranium-REE-gold, and tin-silver mineralization respectivelyPost-accretionary granitoid intrusions and associated volcanic fields that range in age from mid-Cretaceous to early Tertiary contain significant gold-silver-polymetallic resources in the East Central Alaska, Hogatza, and Kuskokwim Mineral belts. Collectively the three main post-accretionary plutonic/volcanic belts of central Alaska are part of the Tintina Gold Province, where exploration since 1990has identified about 848 tonnes gold.

Jan 1, 2000