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By Y. H. Chia, P. Somasundaran

Carrier flotation of anatase from clay using coarse calcite is investigated, together with relevant basic properties of the system including aggregation and zeta potential, under different chemical and hydrodynamic conditions The roles of carrier sue and amount also are considered Mechanisms responsible for selective aggregation and flotation are reviewed

Jan 1, 1983

By S. Lin, Y. J. Wang

Based on systematic definitions of a generalized multiple fan ventilation system, the concepts of an augmented system, its solution curve and the operating points of the original system are introduced. The Quasi-Newton algorithm is applied in combination with the switching-parameter method to ensure a continuous search along an augmented-system solution curve and identify all the possible system operating points on it. Two example networks are analyzed to demonstrate those concepts and the application of the algorithm for identifying operating points of multiple fan ventilation systems.

Jan 1, 1994

By William J. Miles

The inhalation of dust has been a problem in the mining industry since antiquity. Crystalline silica is now known to be the cause of silicosis, a form of pneumoconiosis that is associated with excessive exposure to respirable particles in some mining and industrial environments. Crystalline silica was reviewed by the International Agency for Research on Cancer (IARC) in 1986 and classified as a Group 2A, Probably Carcinogenic to Humans in Volume 42 and Supplement 7 of the IARC Monographs (1987). In 1996, IARC reviewed additional literature and studies published in the intervening decade and recommended that quartz and cristobalite, two polymorphs of crystalline silica, be listed as Group 1, Carcinogenic to Humans. Their recommendations and reclassification were published in 1997 in IARC Monographs 68.[2] In both Monographs, IARC classified amorphous silicas as Group 3, Inadequate Evidence for Carcinogenicity to Humans.

Jan 1, 1998

By R. H. W. Chadwick

We in Kennecott are well aware that Alaskans are interested in the progress of our project at Ruby Creek. We would very much like to be able to present you with a final report at this time and tell you about a new mine. I'm afraid, however, that it will be several years at best before such a report can be made. This, then, is an interim report to describe briefly some of our findings to date, and to acquaint you with some of the problems, both geologic and economic, which must 5e resolved favorably before we can talk about a mine. There are several things about this project which make it unusual and interesting to those of us who have been connected with it. Firstly, there is the fundamental importance to Alaska, in the present stage of its economic history, of any undertaking which offers promise of turning a natural resource into a competitive export product. I am sure all of us would get a lot more satisfaction out of having a part in bringing in a new mine in Alaska than we would out of adding another one to the long list in, say, Arizona.

Jan 1, 1960

By R. J. Kolada

The ventilation systems of coal storage silos are normally capable of rapidly dispersing any accumulations of methane in the atmosphere above the coal pile surface. However, the results of an investigation which is presented in this report show that hazardous concentrations of methane can accumulate within the coal pile. Methane trapped within the coal pile is released into the atmosphere of the loading gallery when coal is discharged from a silo. If the methane released is of a flammable concentration it is necessary to ventilate the gallery to reduce the risk of an ignition. This report proposes a simple test, which, after further investigations may prove to be an effective method to calculate gallery ventilation requirements.

Jan 1, 1985

By Hervé Le Bissonnais, Jean-Pierre Janin, Anne Bergère, Pierre Renier

"The most important impact on the environment of a tunnel excavation is the creation of surface settlements. Nowadays, the mechanized tunneling allows minimizing the settlements, applying a confinement pressure which counterbalances the ground de-confinement. It is thus essential to determine the correct amount of confinement pressure. In this paper, the authors present a 3D numerical study simulating the EPB-TBM excavation of a water tunnel, in the Flanders clays (north of France). Firstly, a simplified 3D simulation, based on the concept of instantaneous longitudinal settlement curve, was performed to predict the surface settlements for different values of heading confinement pressures. Secondly, the same pressures were tested by the EPB-TBM in a monitoring zone. The comparison between the prediction settlements and the measurements was very satisfactory and allowed validation of the numerical approach and the choice of the optimal confinement pressure value for a sensitive area of the project. INTRODUCTION The excavation of a tunnel can create displacements of the surrounding soil which may affect existing structures and generate unacceptable dysfunction. The development of the closed shield tunneling has permitted to reduce the volume loss generated around the excavation and consequently the surface settlements. In this case, as explained by different authors (Clough et al., 1985; Kastner et al., 1996; Mair and Taylor, 1997), the ground movements are influenced by the TBM works: the heading confinement pressure, the shield overcutting and conicity, the annular void grout injection parameters, the segment concrete lining rigidity, the consolidation of the grout. Hence, in the tunnel design, it is important to take into consideration these different processes of the excavation works to simulate correctly the tunneling process."

Jan 1, 2016

By A. D. Davis

This project took a watershed approach in the evaluation of water-quality impacts from past mining activities and current restoration projects in the Bear Butte Creek basin, a small and well defined drainage in a heavily mineralized area of the northern Black Hills. The basin contains numerous inactive and abandoned mines as well as a currently active heap-leach surface gold mine. Bear Butte Creek normally loses all of its discharge to sinkholes in the Madison Limestone aquifer and thus can affect the water quality of this regionally important water resource. Water-quality data were analyzed, stream surveys were conducted, and two abandoned mine restoration projects were monitored to evaluate the effectiveness of the watershed approach and to identify practical remediation techniques that could be applied to other watersheds. A geographic information system (GIS) was developed to organize information on stream quality, abandoned mine locations, and other geologic and hydrologic data. The watershed approach toward assessing and reclaiming abandoned mines appears to be effective when compared to a point-source approach that might improve water quality at specific sites but not result in significant overall improvement to the watershed because of adjacent sources.

Jan 1, 1997

By J. R. Heberger

"The Safety Pays in Mining web application, developed by the National Institute for Occupational Safety and Health (NIOSH) Mining Program, helps mines determine the potential costs associated with mining injuries. This web app groups injuries by type, either by the cause of the injury or by the nature of the injury. When the user selects one of over 30 common types of mining injuries, the app provides information on the distribution of costs of workers’ compensation claims for that type of injury. Based on other user inputs, Safety Pays in Mining will estimate the total costs of the selected injuries, including an estimate of additional indirect costs, the estimated impact of total injury costs on mining company profits, and provide some examples of other items (services, equipment) on which companies could spend the savings that result from the prevention of injuries. This paper reviews the Safety Pays in Mining web application by discussing the development of the app, how it is used to show the true costs of mining injuries, and how mines can benefit from using this app. INTRODUCTION Injuries on the job cause pain and suffering. They can also profoundly affect profits and daily operations. In addition to paying direct costs or increased premiums for workers’ compensation insurance, a company might need to pay overtime for other workers to fill an injured worker’s job role, cover training costs for a replacement worker, or divert administrative resources in the wake of an injury. Safety Pays in Mining is a web app that estimates the distribution of these injury costs and assesses the impact that occupational injuries have on a company’s profits. The costs of specific types of occupational injuries in mining are not readily available as mining and insurance companies don’t usually share this information. As a consequence, companies only have cost information based on previous experience with their own employees. Therefore, if a mine never experienced a finger amputation for one of its miners, it would not be aware of the possible costs associated with this type of injury. In addition, injury costs are unique in that the cost distribution is so wide — with half of the injuries in our dataset having mean costs higher than 90th percentile costs — just using the average cost of a specific injury type does not provide adequate information. Some injuries involve immensely high costs, and even though the risk of these high-cost injuries occurring is low, mines need to be aware of their potential impact on their company’s financial health."

Jan 1, 2018

By Omar A. Muhtadi

Brohm Mining Corporation, in conjunction with Geobiotics, Inc. has nearly completed a pilot heap biooxidation test on sulfidic ore from the Gilt Edge Mine near Rapid City, South Dakota. Some results from the pilot testing have shown the correlation between the extent of biooxidation and the increase in cyanide gold recovery seen in the laboratory. Bench scale testing showed approximately a 1: 1 correspondence between percent biooxidation and percentage increase in gold recovery. The economics of large scale biooxidation were also evaluated in terms of increased gold recovery versus the time and cost of biooxidation. In the pilot test, the rate of biooxidation became limited by the acid water neutralization system. Later in the test, measures were taken to overcome this problem. Results from bench scale column bioleach testing showed that the Gilt Edge sulfide ore is quite amenable to biooxidation with a substantial increase in gold recovery with just partial biooxidation. Direct cyanide gold recovery of 51 % on ore crushed to -3/8" was enhanced to 82-85% after oxidation of37% of the sulfide as measured by iron. Laboratory experiments also showed that the slow rate of biooxidation of this ore could be accelerated by removal of metal sulfate build up from the leach liquor. The combination of these normally non-toxic metals became inhibitory to biooxidation if not removed by the neutralization circuit.

Jan 1, 1995

By D. H. Steve Zou, Cui Lin

"This paper first discusses the basic attributes of sustainable mining and the responsibilities of various steak holders including mining companies, governments, and engineers. It is followed by a brief overview of the current practice on regulations, inspections, waste management and mine closure planning in Canadian mining industry. A case study is then presented as an example of sustainable mining where mine planning, mineral recovery, environment protection, reclamation and community development were integral parts of the overall strategy. A comparison of the mine site before and after mining is made to demonstrate the ""best practice"" in modern mining.Sustainability in Mineral Resource Development Extraction of mineral resources and other natural resources on the Earth has been and will continue to be an essential activity necessary to support human’s life. We live on the planet and depend on the available resources to survive. The extracted materials form the base to support modern life. However, we must be aware of the fact that mineral resources are limited on the Earth and may not last forever. Every time we extract one ton of materials, there is one ton less. They are not able to regenerate or regrow. One can ask a simple question: How long will they last? Or, is there anything left for our great grandchildren and many generations to come? The answer is not simple. Some minerals have become scarce or about to deplete. Some minerals may last longer. The reserve of a type of minerals depends on what we have discovered and the minable amount depends on accessibility and technology we have. Even if there are minerals in the deep ground, we may be limited by our technological capability. At the same time, we also need to understand the action of mineral extraction from the ground and the consequences of that action. Mineral extraction is a very hard work. We must break the ground to extract the ore, either through surface mining or underground mining. This action means disturbance of the land where we live. The disturbance is much more visible in surface mining than underground mining. The disturbed land, if not properly reclaimed after mining, is not going to be reusable. The very purpose of extracting minerals from the ground is to support our life but the action has a negative impact on our life. How can we reduce and limit disturbance of land from the action of minerals extraction? How can we make the disturbed land reusable? These issues must be properly addressed and a balance achieved."

Jan 1, 2017

By M. Manrique

Various pyrometallurgical methods for treating Ilmenite and Zircon concentrates are reviewed. Laboratory experiments, using a thermal plasma reactor, have been performed to evaluate: the conversion of ilmenite to TiC or TiC-Fe and the conversion of zircon to ZrC or ZrC-SiC. Results are examined and possible processing routes are identified.

Jan 1, 1996

By W. J. Wuest

The U.S. Bureau of Mines (USBM) has recently developed a rock mass classification system for evaluating the structural competency of bedded roof strata; the Coal Mine Roof Rating, or CMRR. When compiled with the companion Lotus 1-2-3 spreadsheet, which is simple to learn and use, CMRR data are a useful tool with applications to longwall gate road pillar design, safety hazard mapping, and artificial roof support analysis. This paper demonstrates these applications under actual conditions found in current U.S. mining operations.

Jan 1, 1995

By Changhong Huang, Y. J. Wang

Proceedings of the 6th US Mine Ventilation Symposium SME, Littleton, CO, 1993, pp. 153-161.

Jan 1, 1995

By Kourosh Shahriar

The occurrence of rock falls in underground coal mines entails detrimental effects as fatal or non-fatal injuries on workers, stoppages in mining operations and breakdown of equipment. In this paper, a risk assessment approach on the basis of a decision analysis trend is employed in order to assess the possibility of and manage roof falls. Risk is then assessed by determination of likelihood of occurrence and the cost of consequences (outcomes). In this regard, collected real roof fall data from Tabas and Kerman coal regions comprising of several underground coal mines are used. It is concluded that the annual accidents due to the roof falls occurrence in the all investigated mines are so high that it is economically feasible to improve the support systems and to implement a suitable educational program as well as an accurate supervision and other elements of safety management.

Jan 1, 2009

By S. Garcia

The Minera Yanacocha operation presents various operating challenges, due to the complex structure of several heaps interconnected with ponds and gold recovery plants. A comprehensive process model has been developed in order to better understand the effects of certain operating parameters on issues such as water usage and inventory. An integral component of the water/mass balance of the process is a model of each heap that describes the flow and chemical behavior based on the individual characteristics of the heap. A computational fluid dynamic (CFD) software framework is used to model the individual heaps. The structure, calibration and validation of the model are described. Several examples demonstrating application of the process heap model are presented for the La Quinua heap. The effects of loss of solution flow to the heap (i.e., pump failure), increased cyanide levels in applied solutions and higher copper head grades on the process operation and balance are investigated with model simulations and compared to the baseline operating conditions. An example of estimating gold production and inventory based on projected heap loading plans is provided.

Jan 1, 2010

By D. L. Whiting

Dump leaching and ,in-situ solution mining have received considerable attention during the past few years due to their apparent economic viability and minimal environmental impact. Solution mining actually dates back to the 17th century when leaching of copper ore was first reported. However-, modern day leaching didn't begin on a wide scale until the mid-1900's. In-situ mining for copper, nickel, salts, and oil shale is currently looking more attractive as the technology advances. Presently, about 15 percent of the copper production in the United States is from leaching operations at approximately 14 active sites, the largest of which are the waste dumps near the Bingham Copper Mine, Utah. To establish a common background, the discussion is centered around state-of-the-art conditions. For dump leaching, complications inherent to the physical conditions and chemical reactions such as channeling, porosity and permeability, sorption, air flow, rock alteration and pH control are discussed. Emphasis is made on those conditions which render solution recovery rates and solution mineral concentrations unpredictable. By illustrating typical and actual field conditions, the generally accepted flow theories for both dump leaching and in-situ solution mining, including rubblization, are presented. For in-situ mining, hydrogeologic techniques such as geophysical well logging, aquifer testing and digital computer modeling are also discussed. The importance of artificial fracturing and well stimulating to solution injection and recovery is made with regard to project development. Finally, the subject of water pollution control techniques and the potential impact of the

Jan 1, 1977

By J. A. Organiscak

This paper describes the research con-ducted on bit wear and respirable dust generation conducted by the US Bureau of Mines (USBM) and West Virginia University (WVU), a member of the Generic Technology Center on Respirable Dust. The USBM investigated wear, energy and dust characteristics of various conical bit designs when cutting rock. WVU studied the functional relationships between wear, cutting force, energy, and dust of one conical bit type when cutting coal. The objective of the USBM study was to identify qualitative bit selection guidelines for cut-ting rock; WVU's research objective was to determine optimum bit replacement guidelines. These research studies both found that bit geometry (a function of bit design and wear) influences energy consumption and dust generation. Bit selection and replacement recommendations are given.

Jan 1, 1995

The Bureau of Mines has studied 260 underground coal mine fires which occurred from 1970 through 1989. Every fire had the capacity to be hazardous to life and property, however upon closer examination some were found to be inherently more dangerous than others. Our research involved reviewing and recording specific information contained in published Mine Safety and Health Administration fire accident reports. The objective was to determine if degrees of hazard relative to fire source or location could be construed from information contained in the reports. We specifically looked at the propensity for fires to cause injuries and fatalities as well as the need to seal the area in order to extinguish the fire. Relative to all underground locations, this review found that fires occurring in main haulage-ways were most likely to cause injuries and fatalities as well as require sealing of at least the immediate area to extinguish.

Jan 1, 1993

By Daniel A. Jones

The Surface Mining Control and Reclamation Act of 1977 establishes a nation-wide program requiring the Secretary of the Interior, through the Office of Surface Mining Reclamation and Enforcement, and the States to protect against the adverse effects of coal mining and to reclaim previously mined lands left without adequate reclamation. The Act requires coal mine operators to: restore the land to approximate original contour, return the land to a condition capable of supporting prior potential uses, protect the hydrologic balance, segregate and restore topsoil, control blasting to prevent damage and injury, establish vegetative cover, and control surface effects of underground mining. The Act also establishes: a reclamation fee on coal, a program to assist small operators, a program to give technical and financial assistance to State programs, State Mining and Mineral Research Institutes., a program for designating areas as unsuitable for mining, and a study on surface mining of minerals other than coal.

Jan 1, 1977

By A. P. Cook

Methane Rating has been developed from a need, in South Africa, for quick and simple measurement of coal face methane characteristics. It employs proven existing direct measurement methods, adapted specifically for rapidly advancing coal face conditions, to deal with the short term high release rates encountered during continuous miner coal cutting. The Rating is a comparative value, relative to the normal or average conditions encountered within a maintained data base. The seam gas content and the initial emission rate are plotted against each other on a graph, where they are compared with the average conditions to obtain the rating. The higher the seam gas content, and the higher the initial methane release rate, then the higher the Methane Rating, on a scale of 1 to 4. Methane being released from a newly mined coal sample is measured once underground, from a sealed gas-tight canister. The sample is returned, still sealed, to surface and milled to rapidly release the remaining methane. It is later intended that the milling process is also completed underground. Applications include the identification of changing methane conditions, outburst prone conditions, methane emission against advance, and mining in devolatilised coal.

Jan 1, 1998