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By R. K. Sinha, B. S. Choudhary, Desh Deepak, A. K. Mishra, Hemant Agrawal, Shankar Kumar

There are several methods (empirical, statistical, and machine learning tools) to calculate blast-induced ground vibration. Still, due to complications in the blasting procedure, under varying blasting loads and strata conditions, it is not easy to predict and simulate blast vibration precisely. Therefore, a study was conducted to simulate the field blast data in Ansys software using explicit dynamics. For this study, monitoring of ground vibration for 20 single hole blasts was carried out. The density of emulsion explosives was in the range of 0.9 to 1.15 g/cc. In the laboratory, rock properties were determined from the rock sample collected from the mine site before blasting. The in-hole velocity of detonation (VoD) and the density of the emulsion explosive were also determined. These parameters were used for numerical analysis to know the ground vibrations at specified points. The results of ground vibration predicted by the model are validated using field data.

By D. V. Keller

The use of a static bath of a heavy liquid of intermediate density between two mineral phases has been employed for beneficiation for over one-hundred years (1-6). In the case of the heavy liquid separation of coal from its included mineral matter, laboratory (3) and commercial (2,4) techniques have employed a halohydrocarbon or mixtures thereof, or solutions of inorganic salts and water with a specific gravity in the range of 2.0 to 1.30. As a laboratory tool, the heavy liquid separation is generally regarded as a standard permitting the "ideal" separation of a product coal and reject mineral matter. Each of the products in this case is polyphase since the separation is only based on apparent specific gravity of the product or reject material. The "Otisca Process" is an anhydrous heavy liquid separation process which employs a parting liquid with certain physical and chemical characteristics which make it particularly advantageous for expanding the laboratory separation process into the realm of commercial coal cleaning. The two key characteristics of the parting liquid are: 1) the heavy liquid does not react significantly with the coal product or reject material, and 2) the liquid permits complete dispersion of the coal product particles throughout the separation bath. The first point, i.e., the lack of liquid coal reaction (7-11), may be cited as one of the major reasons for the failure of other attempts at commercialization of heavy liquid processes. For example, if reaction does occur between the heavy liquid and coal or mineral matter, complete heavy liquid recovery becomes a very expensive complex process. The costs of heavy liquids alone prohibit their loss in the process as will be demonstrated later.

Jan 1, 1977

By B. Weaver

Every year Pit & Quarry Magazine surveys the industry to produce their annual review. Here's a sampling of some of the statistics the survey produced from the end of the year 1994 survey.

Jan 1, 1995

By E. Z. Casassa

There has been a recent revival of interest in concentrated coal/water slurries as a substi¬tute for fuel oil or for coal/oil mixtures, particularly in electric power generation. The idea is not a new one. Coal/water slurries were transported by pipeline in the U.S. in the early nineteen-sixties, and the Black Mesa coal pipeline has been in operation for several years, while in Germany, coal/water slurries were being burnt for power generation in the early nineteen-seventies, as described by Merten and Höner (1972). Since coal is not a pure substance but a carbonaceous mixture, the different chemical and physical behavior of coal/water dispersions from different deposits must be understood in order to optimize the properties of the result¬ing slurry fuels. Since minerals which are minor constituents of coal may also strongly affect slurry properties, coal chemistry may vary considerably even within a single deposit. Thus it is unlikely that there will be a single formula for optimizing the slurry properties of all coals, and even the answer for coal from a single source may change with time.

Jan 1, 1983

By Jiawang Hao, Qinglong Zhang, Liang Han, Chuhan Wang, Shenfang Chen, Lan Qiao

The surface collapse and surrounding rock failure caused by goaf instability are the mining disasters that cannot be ignored. It is of great value to evaluate the stability of goaf accurately and treat it economically for the mine safety and the maintenance of ecological environment. However, in previous studies based on numerical simulation methods, the spatial complexity and the irregularity of actual goaf were not considered. Therefore, based on the internal space data of goaf obtained by high-precision laser detector, the goaf stability was comprehensively analyzed through Plaxis software and two-stage fuzzy judgment theory in this study. To effectively improve the goaf stability, the optimal backfill parameters for the goaf treatment were obtained by a series of mechanical tests. The research results provide some good references for the stability evaluation and the treatment of underground goaf.

Sep 26, 2023

By Xuehui Li, Xinshuai Shi, Jun Wang, Jianguo Ning, Shang Yang, Zhaohui Zhang

Pressure relief is an important step in preventing and controlling rock burst disasters. Hydraulic slotting has emerged as a strategy for pressure relief and energy release in roadway surrounding rock. There is no qualitative description for the response relationship between hydraulic slotting parameters and the degree of pressure and energy release in a roadway, which is a scientific problem. In this paper, theoretical analysis, numerical simulation, and on-site industrial practice were comprehensively used. First, a structural model for the pressure relief and energy release of coal by hydraulic slotting in a deep roadway was established, and the pressure relief and energy release principle by hydraulic slotting was revealed. The principles and methods for determining hydraulic slotting parameters in the roadway were proposed. Three evaluation indices for the pressure relief and energy release effect of coal after hydraulic slotting were proposed, namely, the stress ratio of coal, elastic energy density ratio of coal, and displacement rate of the roadway rib. According to the evaluation indices, the degree of pressure relief and energy release was divided into three levels: reverse pressurization, full pressure relief, and transitional pressure relief. Then, a FLAC3D numerical model was constructed, the levels of pressure relief and energy release under different hydraulic slotting parameters were analyzed, and the optimal slotting parameters were determined. Finally, on-site industrial practices were carried out in Panel 7312 of the Xinhe Coal Mine. An effect test showed that the effect of pressure relief and energy release was remarkable after hydraulic slotting was adopted on the roadway surrounding rock, which can effectively reduce the risk of rock bursts. These research results can further improve hydraulic slotting technology systems and provide a theoretical basis and technical reference for the stability control of deep roadway surrounding rock.

Sep 20, 2023

By W. A. Wilkinson

Mine planners are under pressure to evaluate the impact of changing economic times and newly acquired data on their mine plans. Incorporating changes such as commodity prices, customer sales, fluctuating cost assumptions and newly acquired geologic data requires quick turnaround for model building and planning to keep mine plans on pace with changes as they occur. Because of the length of time required to perform some of the geologic modeling and mine planning tasks, planning frequency may not be keeping pace with the frequency of change. To meet these challenges, one leading North American mining company successfully increased the frequency rate and accuracy of its mine plans to stay current with incoming data, ensuring its mine plans reflect the latest information, thereby minimizing or eliminating production cost variance.

Jan 1, 2010

By S. S. M. Chan

The design of most underground support systems has largely been based upon empirical rules. This design method has proven to be satisfactory in most cases as witnessed by the number of successfully completed works. However, the adequacy of this approach to the developing technology of ground support systems associated with deep excavation has not been substantiated. In cases where the material has definite time-dependent behavior parameters, rules of past experience become extremely vague and conservative. The Spokane Mining Research Center is currently engaged in extensive research to develop rational design methods for underground structures which will account for the many interacting factors such as in-situ properties of the rock mass, excavation methods, proposed types of support system, construction sequence, and environmental variables. The information presented in this paper pertains to only a segment of the research program,

Jan 1, 1971

By K. Ananthpadmanabhan

Hydrolyzable surfactants such as fatty acids and amines undergo, in addition to micellisation and precipitation, various associative interactions in aqueous solutions to form ion molecular complexes such as acid-soap, dimers etc. depending upon the solution conditions such as pH. The interaction of these collector species with the mineral surface and with other dissolved species in solution will play a significant role in determining the interfacial processes such as adsorption and flotation. Marked differences in the hydrophobicity imparted to the mineral surface depending upon the solution conditions such as Ph can be attributed to possible differences in surface activities of the above complexes. This aspect of solution chemistry of flotation systems is discussed here for two widely used collectors namely, oleic acid and dodecylamine. Equilibrium species distribution diagrams based on the available literature .data and on estimates of energy of interactions between molecules, have been obtained for oleic acid and dodecylamine solutions.

Jan 1, 1978

By Karoly (Charles) Kocsis, August Greth, Jon Fox

"It is the duty of the mine operator to ensure the mine environment is healthy and safe for the mine workers. For deep and hot underground mines, this requires maintaining adequate working temperatures by means of mitigating the heat load generated by strata, auto-compression, mining equipment, explosives, ground water and human metabolism. The heat load is best reduced by minimizing the amount of heat transferred to the mine air from these sources and through the use of efficient ventilation with effective cooling systems. The heat emitted by mining equipment and vehicles contributes a significant proportion to the combined heat load of an underground mine. This is especially a problem for diesel equipment due to the fact that besides heat, a large amount of water vapor is produced, which increases the humidity in the production workings. Diesel engines have proven advantageous in recent history due to their high power output and reliability. However, as mines continue to become more mechanized and deeper the climatic problems introduced by elevated heat generation will continue to rise. With that, the issue of heat generated by diesel equipment must be addressed.The economic alternative for diesel engine equipment fleets in underground mines is the electric engine. Technological advances in battery technology, increased mechanical output and improved reliability have made the electric engine significantly more competitive in comparison to diesel engines. Because electric engines do not utilize internal combustion, the heat produced by them is significantly less than the diesel engines. Battery-powered mining equipment likewise eliminate diesel particulate matter (DPM) produced by diesel engines. Utilizing battery electric equipment in underground mines provides many advantages, such as: (a) reduced heat load, (b) healthier and safer environment for the mine workers and (c) reduced mine operating costs due to lower ventilation requirements"

Jan 8, 2018

By J. S. Heath

Many disputes related to environmental issues in mining are resolved through often-antagonistic negotiations in a regulatory context or through litigation. These approaches are certainly the best choices for resolving certain disputes. However, just as no single remediation technology is the right fit for every site, so no single dispute resolution process is the best choice for every situation. This paper introduces a range of dispute resolution alternatives (from collaborative decision making through mediation, arbitration, and litigation). Especially when money is tightest, cost-effective dispute resolution(and the outcomes that can accompany it) can have an impact on the bottom line.

Jan 1, 2000

By V. T. McLemore

The Steeple Rock district is a major epithermal .gold-silver district in New Mexico that exhibits district zoning. Five types of ore deposits occur in the district. The base-metal veins (with Au and Ag) form the center of the district and occur along the Carlisle fault. The gold-silver veins occur along northwest-trending faults outward from the base-metal veins. The margins of the district are formed by copper-silver, fluorite, and manganese veins. In addition, areas of older acid-sulfate alteration occur throughout the district and also exhibit zoning: massive silica/chert zone (inner), silicified zone, and clay zone (outer). This alteration overlies regional; alkali-chloride (propylitic to argillic to sericitic) alteration. Synthesis of available data suggests the acid-sulfate alteration is related to a shallow but older epithermal hot springs system. Subsequently, younger epithermal veins formed along faults.

Jan 1, 1994

By Justin Reed, Sara Bewley, Dwight M. Kinnes, Maryam Sadeghi, Ed Hart

This study compares wet gravity and dry magnetic separation for preconcentrating an allanite-rich rare earth ore from the Halleck Creek deposit. Material in the –300/+86 μm size range was treated to define a flowsheet that maximizes total rare earth oxide (TREO) recovery. The ore is dominated by feldspar and quartz, with hastingsite, an iron-bearing aluminosilicate. Because hastingsite’s density and magnetic response closely match allanite, it is difficult to reject using conventional methods. Two separation approaches were evaluated: MG12 spirals for gravity concentration and an Induced Roll Magnetic Separator (IRMS) for dry magnetic upgrading. MG12 spirals performed well in the rougher stage but provided limited gains when used as cleaners. When IRMS was applied as the cleaner stage, TREO grade and recovery improved substantially, showing that a dry magnetic cleaner circuit can effectively replace the wet gravity cleaner step. MG12 spirals remain suitable for highcapacity rougher duty, but dry magnetic separation delivers higher selectivity, simpler operation, and eliminates water use—offering a more efficient and sustainable preconcentration route in water-constrained environments.

Feb 22, 2026

By Linda J. Dahl

The U.S. Department of the Interior, Bureau of Mines is developing a process to selectively extract manganese from oxide ores as part of its in situ leach mining research program. The Bureau is conducting site characterization studies of two manganiferous iron-formation deposits which include: drill core, regional stratigraphic relationships from the existing geologic database, ore body geometry, geologic structure, hydrologic conditions, proximity of ore minerals to the leach fluid paths, surface subsidence potential, and data collected from laboratory leaching experiments. This information is being used to evaluate the technical, environmental, and economic feasibility of in situ leach mining of manganese for these two deposits. This paper will focus on the stratigraphy, mineralogy, ore textures, fractures, permeability, and porosity as they relate to in situ leach mining.

Jan 1, 1992

By J. D. McAteer

It is widely agreed throughout the mining community that federal mine safety and health legislation administered by the Mine Safety and Health Administration (MSHA) deserves significant credit for the past quarter-century's remarkable improvements in miner safety and health. Recently, however, it has been suggested that the mining industry in the United States has now evolved to a point that current mine safety and health law may be obsolete. This proposition deserves attention. Today, I propose to give it the close logical scrutiny that is its due. I conclude that the obsolescence of current mine safety and health law is not supported by the evidence. The existing mine safety and health law continues to serve as a critically important supplement to mine operators' safety programs at a modest cost to the taxpayer. At the same time, trends in a changing industry do call for responsive adaptations in the Federal mine safety and health program. I will argue that timely and appropriate responses to changing needs can be accomplished within the framework of existing legislation, provided federal officials avail themselves of the flexibility provided by existing law.

Jan 1, 1996

By Yucheng Li, De Huang, Yonghong Liu

Mine frictional resistance is one of the essential parameters of mine ventilation systems, and it is of considerable significance for the prevention and control of mine risks and accident hazards. Frictional resistance requires a lot of resources and time and has errors. To reduce the errors of frictional resistance, a regression model of frictional resistance is proposed based on the correlation analysis of the affecting factors. Through the comparative test analysis of seven regression methods, it is found that the classification and regression tree method for solving the proposed regression model has better performance than other methods. The least square error criterion is used to calculate and rank the importance of the factors affecting frictional resistance. The results show that the cross-sectional area of the tunnel, the support method, and the presence or absence of devices or pedestrian ladders have the most considerable influence on the prediction accuracy of frictional resistance. The support methods and cross-sectional areas are essential input variables. Through the combination test analysis of the influencing factors, the results show that the regression model does not have predictive ability when the number of input variables is less than 3 and the best predictive performance cannot be obtained using all the influencing factors. The best prediction model of resistance is to combine the shape of the tunnel, the support method, the presence or absence of devices or pedestrian ladders, and the cross-sectional area. The method proposed in this paper does not require a lot of resources and time investment, and the frictional resistance error is small. At the same time, it solves the problem of resistance prediction with incomplete data of influencing factors and provides a compelling new method for obtaining frictional resistance parameters.

Jan 28, 2022

By Matthew S. Sanchez, Richard J. Lee, Matthew D. Zock, Drew R. Van Orden

"Current Environmental Protection Agency (EPA) risk models and asbestos fiber counting techniques for monitoring airborne exposures treat all fibers as being equivalent and ignore the effect of dimension on toxicity. While this may have been appropriate when modern analytical methods were not available, the measurement world is now fully capable of making the appropriate distinctions. The importance of width as a determinant of carcinogenicity has been recognized for nearly 30 years within the published literature. Stanton,1 in a landmark study of a suite of fibrous materials, found that durable mineral fibers with widths less than 0.25 mm and lengths longer than 8 mm were causally associated with the induction of tumors. Pott,2 in a later study, postulated a fiber toxicity model that agreed reasonably well with the Stanton findings, but extended the concept to include varying toxicity as a function of length and width. Wylie et al.3 reanalyzed samples used by Davis et al.4 and found that tumor generation was strongly and inversely correlated with fiber width. Crump5 testified increasing fiber length was correlated with disease occurrence. Lippman6 reviewed a number of studies and suggested that mesothelioma was closely associated with long, thin fibers. Berman et al.7 published a risk model, which found that disease was correlated almost exclusively with fibers longer than 40 mm and width less than 0.25 mm. Recently, Loomis et al.8 reanalyzed textile mill samples and found that aspect ratios greater than 40:1 were highly correlated with disease. Incorporation of width into risk models has been limited by the availability of data from operating asbestos plants and, in particular, the observation of an asbestos plant for which there is no observable mesothelioma. There have been only limited studies published on the dimensions of asbestos fibers, with a few serving as the primary references in other literature.9_13 A rare opportunity to collect detailed concentration and dimensional data of airborne crocidolite from an operating asbestos-cement plant using modern analytical procedures arose, providing a chance to supplement the existing literature on airborne fiber dimensions. The asbestos-cement plant is located in the eastern end of Cochabamba, Bolivia along Highway 4. Cochabamba is a relatively large city located in the Andes Mountains, approximately 250 km southeast of the capital La Paz. The city sits in a valley that runs east-west with mountains to the north and south. The crocidolite used in the products made at this facility is mined in central Bolivia, approximately 75 km northwest of Santa Cruz. The crocidolite is a fibrous magnesioriebeckite 14 (blue asbestos). Crocidolite fibers from Bolivia were the subject of prior reports suggesting the fibers are generally longer and thicker than crocidolite from Australia or South Africa.9 At the cement plant, the run-of-mine crocidolite was first pulverized using a hammer mill and then sieved on vibratory sieves to produce fibers of limited size ranges for use in the cement. The sieved crocidolite is mixed with other components, including recycled cement product, to produce a slurry that is vacuum filtered into sheet form. The sheets are then manually molded into a corrugated shape, air dried, and sawed (using circular saws) to accepted dimensions. The sawed sheets are cured in soaking pits for 28 days before being shipped to the consumer. Prior to shipping, the sheets are finished by a light hand sanding followed (at customer request) by applying one or more coats of paint. A detailed description of the cement plant and the industrial hygiene results can be found in Van Orden et al.15"

Jan 1, 2012

By J. H. van Laar, C. S. L. Schutte, M. Le Roux

Highly energy-intensive systems prone to wastage are significant causes of unnecessary energy losses in industry. Deep-level mine chilled water reticulation systems fall within this category of inefficient energy-intensive systems. Some techniques (measured baselining, zero-waste baselining, leak detection, and control valves) exist to identify and reduce wastage in mine water reticulation systems. However, these techniques have not been compared, which begs the question of which is more accurate. A need, therefore, exists to compare these methods to determine the effectiveness of each. This study investigates each method and applies them to a case study mine, providing a platform for comparison. These methods identified wastage ranging between 2 and 20 l/s (3–30% of water consumption). The comparative effectiveness of the methods from best to worst was found to be zero-waste baselining, leak detection, control valves, then measure baselining. This study proposes an application procedure combining the considered methods to identify and eliminate wastage on deep-level mine systems more efficiently.

Jan 31, 2024

By J. Hupka

Some aspects of kerosene penetration into tar sand have been investigated. The natural tar sand porosity was measured and used to analyze the performance of the hot water process. Subsequently, pretreatment experiments, using 20 kg tar sand samples (Asphalt Ridge and Whiterocks, Utah), and kerosene as a diluent were carried out at the expected summer temperature (26°C) and the expected winter temperature (-14°C). The natural tar sand porosity accessible by diluent has a crucial impact on the reduction of bitumen viscosity, and influences the penetration time required for successful bitumen separation from tar sand by hot water processing. Thus the tar sand porosity is an important variable which determines appropriate operating conditions. Experimental results indicate that diluent penetration into the Asphalt Ridge tar sand (high porosity) is almost complete after 30 min, whereas for the Whiterocks tar sand (low porosity) the penetration process is much slower, and still not complete after 15 hours regardless of the ambient temperature.

Jan 1, 1992

By Casters B. Foster

The U.S. Department of Energy has undertaken, in a cost sharing partnership with industry and utilities, an extensive coal-oil mixture (COM) combustion program in a number of promising applications. One of these is the injection of COM through tuyeres into a blast furnace in lieu of oil. From work done previously, it has been established that COM can be burned in existing oil, fired facilities. The issues being addressed by the current DOE program are: 1) determination of best available technology to achieve environmentally acceptable operation, and 2) determination of applications for which COM can be utilized economically.

Jan 1, 1978