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By A. Cecala, J. Noll, J. Hummer

The National Institute for Occupational Safety and Health has observed that many control rooms and operator compartments in the U.S. mining industry do not have filtration systems capable of maintaining low dust concentrations in these areas. In this study at a mineral processing plant, to reduce respirable dust concentrations in a control room that had no cleaning system for intake air, a filtration and pressurization system originally designed for enclosed cabs was modified and installed. This system was composed of two filtering units: one to filter outside air and one to filter and recirculate the air inside the control room. Eighty-seven percent of submicrometer particles were reduced by the system under static conditions. This means that greater than 87 percent of respirable dust particles should be reduced as the particle-size distribution of respirable dust particles is greater than that of submicrometer particles, and filtration systems usually are more efficient in capturing the larger particles. A positive pressure near 0.02 inches of water gauge was produced, which is an important component of an effective system and minimizes the entry of particles, such as dust, into the room. The intake airflow was around 118 cfm, greater than the airflow suggested by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) for acceptable indoor air quality. After one year, the loading of the filter caused the airflow to decrease to 80 cfm, which still produces acceptable indoor air quality. Due to the loading of the filters, the reduction efficiency for submicrometer particles under static conditions increased to 94 percent from 87 percent.

Jan 1, 2015

By L. O’Connor, E. Tarshizi

The objective of this work is to provide a detailed review and a list of references in chronological order, comprising 80 recent technical papers, on the use of discrete-event simulation (DES) modeling in mining engineering. In this article, the review papers of published mine simulation projects through 2007 are summarized, and then a comprehensive review of individual articles published from 2008 to 2015 is presented. This survey work also includes analyses of the simulation tools used in the published projects, mining types and applications in order to assess these key features and evaluate the recent state of research in mine DES simulation. In addition, an interactive map visualization for the locations of the simulated projects is made available on a website to benefit current and prospective scholars in the field. The results of this investigation revealed that the most common application of DES in mining had been mining equipment selection and analysis, while ore processing and risk management projects were less frequently reported. The results also showed that modeling surface mines were in the majority, but the trend of publications for underground mine simulations had also increased. According to the results, ARENA was the most popular simulation software package, but several simulation tools that were only used once or twice in the mining projects are also included in this review.

Jan 1, 2018

By L. O’Connor, E. Tarshizi

The objective of this work is to provide a detailed review and a list of references in chronological order, comprising 80 recent technical papers, on the use of discrete-event simulation (DES) modeling in mining engineering. In this article, the review papers of published mine simulation projects through 2007 are summarized, and then a comprehensive review of individual articles published from 2008 to 2015 is presented. This survey work also includes analyses of the simulation tools used in the published projects, mining types and applications in order to assess these key features and evaluate the recent state of research in mine DES simulation. In addition, an interactive map visualization for the locations of the simulated projects is made available on a website to benefit current and prospective scholars in the field. The results of this investigation revealed that the most common application of DES in mining had been mining equipment selection and analysis, while ore processing and risk management projects were less frequently reported. The results also showed that modeling surface mines were in the majority, but the trend of publications for underground mine simulations had also increased. According to the results, ARENA was the most popular simulation software package, but several simulation tools that were only used once or twice in the mining projects are also included in this review.

Jan 1, 2017

By P. M. Krishna

An example illustrates the use of ASTM Standard E901-82, Classification System for Uranium Resources. The example demonstrates the dynamic nature of the process of classification and attests to the necessity of addressing both the aggregate needs of broad-scale resource planning and the specific needs of individual property evaluation. Problems that ,remain in fixing the classification of a given uranium resource include the uncertainty in estimating the quantity of undiscovered resources and resolving the differences that may exist in deciding when the drill-hole spacing is adequate to determine the tonnage and grade of discovered resources.

Jan 1, 1983

By James J. Olson

Most of the projects summarized in this paper are funded under the Bureau's Advancing Metal-Nonmetal Mining Technology program and are part of the in situ mining subprogram coordinated at the Twin Cities Mining Research Center. The borehole mining equipment development, are funded under the Bureau's Advancing Coal Mining Technology program, is essential to accelerated progress in the in situ mining subprogram, and some background information on this concept is included. The initial in situ research projects started in 1971-72 evaluated some of the critical blast design parameters for in situ copper leaching. The present program totals about $1 million per year and includes in-house research projects, cooperative (cost-sharing) projects with the mining industry, and research and development contracts. Two different extraction schemes are under investigation: inplace leaching and borehole (or slurry) mining. The principal commodity targets for the Bureau's improved in situ mining technologies include copper, uranium, coal, and potash. The principal purpose of this paper is to inform the mining industry of the in situ mining research recently completed or being conducted by the Bureau of Mines. In addition the Bureau encourages companies to comment on the program accomplishments as well as offer suggestions on top priority research needs for improving the in situ mining methods described in this paper.

Jan 1, 1977

By Wern-Ping Nick Chen

Durability risks for underground facilities can be underestimated during design phase as compared to well-known geological risks. However, unclear durability requirements can result in construction schedule delay and change orders. Unlike bridges or buildings, a unified underground durability code or standard does not exist. This paper will provide a durability approach for underground facilities, including degradation modes, mitigations, and compliance measures during construction. In addition, this paper will address how to clearly specify durability requirements in a contract document to reduce disputes during construction and discuss key durability tests that are time consuming and will impact construction schedule if not timely planned.

Jun 23, 2024

By Richard E. Ray

Conventional concrete block plastered with a cemantitious coating is the most common material used in the construction of perma¬nent stoppings to direct airflow in underground mines in the U.S.A. All mines experience various degrees of strata convergence depending upon depth of overburden, geological conditions, and type of roof support employed. Strata convergence will cause cracks and joint openings in masonry stoppings, resulting in significant air leakage losses. Where strata convergence is severe, complete structural failure of the stopping can ultimately occur. Reconstruction of damaged or destroyed stoppings adds expensive overhead to mining operations, and even greater expenses are incurred from the additional fan horsepower required to overcome leakage losses. Ideally, a stopping should maintain high resistance to airflow while yielding to strata convergence. By properly incorporating "Max-Seal" polyisocyanurate rigid foam material within the masonry block structure, stopping service life can be increased several-fold in mines experiencing strata convergence problems such as floor heave, roof loading, and lateral rib movement.

Jan 1, 1984

By M. A. Reyes, L. Yan

Heat and humidity buildup withn refuge alternatives (RAs) may expose occupants to physiological hazards such as heat stress. The Mine Safety and Health Administration (MSHA) regulations require RAs in underground coal mines to provide a lifesustaining environment for miners trapped underground when escape is impossible. RAs are required to sustain life for 96 h while maintaining an apparent temperature (AT) below 95 °F (35 °C). The National Institute for Occupational Safety and Health (NIOSH) tested a 10-person tent-type RA, a 23-person tent-type RA, and a 6-person metal-type RA in its underground coal mine facilities to investigate the thermal environment over a 96-h period. The test results showed that mine air and mine strata temperatures surrounding an RA occupied by simulated miners (SMs) increased over the 96-h test period. The test results suggest that RA manufacturers should consider this increase in temperatures when calculating and evaluating RA components during surface and laboratory tests. The findings can equip stakeholders with additional considerations for calculating the interior heat and humidity temperature profiles for occupied RAs not tested in situ.

By Evan Dressel, Mark S. Diederichs, Kathy Kalenchuk

As hard rock mining develops deeper over time, there is an increasing need to predict the spatial and temporal distribution of adverse seismogenic rockmass reaction to mining. Real-time monitoring and feedback of mine data are used to tactically manage risk associated with induced-seismicity; however, strategic risk management requires reliable tools for forward predictions of seismic hazard. The forward prediction of seismic hazard is strengthened by understanding of potential seismic intensity, which often relies on well calibrated mine-wide numerical models. This paper uses a case study to explore how future seismogenic potential and the nature of future seismicity can be domained according to numerically predicted stress-strain paths at past seismic event locations. Delineation of high confinement seismogenic volumes vs. lower-confinement, high-strain seismogenic volumes at the mine-scale can be achieved, based on a loading and unloading stress path analogue, to refine understanding of seismic intensity. Practical qualitative and quantitative methods to achieve this delineation will be demonstrated. Once seismogenic mode (high-stress vs. high-strain) is identified, detailed analyses of seismic source parameters demonstrates change in seismic hazard between the domained volumes.

Apr 26, 2022

By R. A. Allwes

In-plane bending and torsion tests were conducted on full-scale masonry walls to evaluate three post-reinforcement designs. The designs were developed to minimize longwall mine subsidence damage to existing residential masonry foundations. The bending tests show that vertical and horizontal post tensioned tendons significantly increase the resistance of a masonry wall' to in-plane bending. The torsion tests reveal that post tensioned tendons increase a masonry wall's limit of deformation but do not increase its torsional stiffness. The torsion tests also show that the masonry units minimally contribute to the torsional stiffness of a masonry wall.

Jan 1, 1995

By L. J. Vincze

The program of study of pellet binder materials was begun by the ORF in 1963 to examine various Canadian materials as substitutes for bentonite which is imported in large tonnages (199,270 tons in 1969) from the U.S.A. for Canadian pellet plant operations. Most of the raw bentonite used in Canada originates in Wyoming, North Dakota and more recently Greece, resulting in relatively high transportation costs to pellet producers. Some Canadian bentonites available in Western Canada (Alberta) can be beneficiated for uses as pellet binders but could not compete in cost with U.S. sources due to the cost of beneficiation and the higher rail transport charges to Eastern Canada. It is difficult to find a substitute for bentonite, and many materials have been investigated by research groups but, so far, no economic substitute is in use. However, some success is apparent in studies of low cost materials such as clays, sea weed, peat moss and low grade coal, The work done by the ORF over several years has covered systematic test¬ing of Ontario clays, lignite, some types of tree bark, waste sulphite liquors of various kinds, and peat moss as binders for iron ore pellets. The major effort has been concentrated on peat moss and has included a study of the influence of different additives. Since analysis of peat moss for humic acid is difficult and time consuming, a certain amount of time was devoted to development of improved methods, the most useful of which was a spectrophotometric method based on extraction of peat by sodium pyrophosphate for determination of humic substances. In the present paper, only the most recent work concerning the use of peat moss with suitable additives is discussed in detail, since it is the most conclusive and best documented portion of the program.

Jan 1, 1971

By B. W. Stunkard

Hibbing Taconite Company is located by the cities of Hibbing and chisholm near the center of the Mesabi Range, approximately 169 km (105 miles) from the Canadian Border. The plant site is equidistant from these two communities, about 6.4 km (4 miles) from each. A 169 km (105 mile) railroad connects us with the port of Superior, Wisconsin, where the pellet production is loaded into lake carriers for lower lakes destinations. Immediately to the south of the mine area is the world famous Hull- Rust-Mahoning Mine which produced more than 700 000 000 million tons of red ore between the years 1893 and 1973.

Jan 1, 1979

By Ernest Bohnet

Each mining operation is unique in some aspect ownership; ore body location, size, geometry, grade, mineralogy, hydrology, or geotechnical parameters; or constraints such as environmental regulations. However, all mining operations are alike in one aspect; the prime objective of any mining project is to maximize the return on the investment. This is the golden rule, or in the language of mining, the investor?s law of conservation. A mineral resource, by definition, does not become a minable reserve unless the mineral or minerals can be extracted economically (and legally). The three preceding sections have covered the various types of surface mining options. The choice of the most economic method is dictated primarily by the type of de-posit to be mined, the mining rate, and the physical characteristics of the deposit.

Jan 1, 2008

By Wedam Nyaaba, Samuel Frimpong, Bruno Ayaga Kansake, Irene Akalanyaba Ateng

Haul truck capacities have increased due to their economies of scale in large-scale surface mines. These high-capacity trucks impose dynamic loads on haul roads. A previous study estimated the dynamic forces imposed by ultra-large trucks on haul roads to be more than three times the static load. These dynamic forces exacerbate haul road stresses and deformation. Current haul road response models are 2D and use static truckloads for low-capacity trucks. No models capture the ultra-large truck dynamic effects on haul road structural response. This study uses 3D finite element (FE) modeling to compute the haul road response to ultra-large truck dynamic loading. The dynamic forces were modeled using multibody dynamics (MBD) in MSC.ADAMS. These forces were used in an FE model developed, verified, and validated in ABAQUS, to simulate the response of the haul road to the dynamic truck forces. The road was modeled using an elastoplastic Mohr-Coulomb model. The results showed that road deformation decreases with increasing layer modulus and increases with increasing payload. Increasing the base modulus from 100 MPa to 450 MPa reduced the maximum deformation from 258 mm to 62 mm. When the subbase elastic modulus increased from 100 MPa to 500 MPa, the maximum deformation decreased from 160 mm to 84 mm. Increasing the payload from 0 to 120% of the rated load increased the maximum wearing surface deformation from 131 mm to 216 mm. This study forms a basis for designing structurally competent haul roads for improving haulage efficiency and truck and operator health.

Jan 7, 2023

By J. R. R. Bowling, A. McFadden, M. Francoeur

The abstract discusses the increasing use of extensive duct-fan systems in underground hard-rock mine development. It highlights the challenges of designing these systems, particularly the risk of partial vacuum and the need for careful booster fan positioning. The paper explores factors influencing the design of these systems, including component limitations, operational wear margins, and power constraints. It also defines the concept of partial vacuum and its impact on ventilation ducts. The authors propose an algorithmic approach for specifying the location and blade pitch of in-line booster fans to prevent system failure.

Mar 17, 2022

By D. K. Marjaniemi

The U.S. Bureau of Mines inventoried and characterized mineral sites and production plants within 200 km of the border in both the U.S. and Mexico. Sources of information included the USBM Minerals Availability System, the USBM Automated Mineral Information System, the USGS Mineral Resources Data System, the Mine Safety and Health Administration Address/Employment File, and the literature. Three hundred seventy-eight major construction material and industrial mineral properties were identified and characterized in the U.S. and Mexican parts of the Borderlands. Sixty-six major metallic mineral properties were identified and characterized in the Mexican part of the Borderlands.

Jan 1, 1996

By Richard M. Chamberlin

Perlite is an altered rhyolitic glass with 2 to 5 wt % water that expands or "pops" when heated quickly to plasticity while evolving steam to form lightweight, glass foam. Commercial perlite deposits in New Mexico are well-developed zones of chemical weathering (hydration) superimposed on highly permeable and thick glassy zones at the chilled upper surface and toes of high-silica-rhyolite lava flows and lava domes. The maximum tonnage of glass in these volcanoes was predetermined by their unique eruptive histories. New Mexico perlite production (80% of US production of 571,00 st) is mostly from the 3.9 Ma high-silica-rhyolite lava flows at the No Agua Peaks volcanic center. The primary vent at No Agua is defined by a 900 ft-high rubidium-rich composite lava dome, known as West Peak, that contains minor perlite reserves. Slightly less rubidium-rich lava squeezed out from under the west flank of the dome to form relatively thin (250 ft) but highly vesicular lobate flows that now consist of about 50 % recoverable perlite. Finally, rubidium-poor lavas were extruded from a radial dike on the northeast flank of the dome. These thicker (400 ft) flow lobes contain about 20 % recoverable perlite. The largest mass of lava does not always contain the most perlite. The thinner (west) flow at No Agua yields the largest perlite reserves rather than the large composite lava dome or thicker (east) flow.

Jan 1, 1994

By J. E. Dreier, R. E. Scheffel, A. Guzman

"This paper outlines a comprehensive, cost-effective testing program for the acid-ferric sulfate heap leaching of oxide, supergene and primary copper ores. It is based on extensive experience in copper heap leaching and uses the many technological advances in the field developed over the past several decades. The approach described requires firstly a detailed resource evaluation, then a hydrodynamic characterization of representative samples and, finally, a focused metallurgical testing program. The principles communicated here can be applied to other acid leachable minerals. The program varies considerably from conventional testing in its disciplined, orderly, step-by-step approach, its application of hydrological and chemical principles to leaching, and its reliance on fewer, more tightly controlled column tests. The purpose of the test program is to optimize the financial, time and other resources devoted to the program, while minimizing the financial risks to the development company or companies and the project funding providers. IntroductionThe major goal of any process development testing program should be the successful implementation of the project. With respect to heap leaching, the metallurgical testing program plays a critical role in the larger objective, as described in Scheffel (2013, 2014). McNulty’s series of papers (1998, 2004, 2014) confirm that the success of any project is directly proportional to the extent and quality of the testing program on which the process is designed.Therefore, a key development objective is to conduct a well-focused metallurgical test program. While the primary focus of this paper is copper, the acid leaching of any substance would benefit from a similar approach.This paper addresses primarily the sulfate system, which is compatible with the bioleaching of sulfide minerals. Nicol et al. (2011) described the advantages of the chloride leaching of copper sulfide minerals. United States patents Nos. US 2009/0173188 A1, US 8,597,933 B2 and US2015/0232963 A1, assigned to BHP Chile Inc. and BHP Billiton S.A. Ltd, describe methods for both the oxidative and nonoxidative leaching of primary and secondary copper sulfides. Reyes (2013) and Ipinza and Flaquer (2014) described commercial applications of chloride-based heap leaching. The testing disciplines discussed in this paper will also apply to the development of an acidic chloride leaching system."

Jan 1, 2016

By Joseph M. Zigich

The Anaconda Minerals Company operates a molybdenite and copper producing mine and mill facility near Tonopah, Nevada. Included with the milling facility is a ferric chloride leach plant for removal of copper mineralization from the molybdenite concentrates. Discussed are the engineering and construction schedules associated with the leach plant. The chemistry associated with the process along with a description of the process flow, equipment, and operating parameters are contained in the paper.

Jan 1, 1983

By P. O. Lindahl

The U.S. Bureau of Mines initiated research to improve the safety and efficiency of transporting coal from deep underground mines using a balanced air-lift hydrohoist. A 50-m-high pilot-scale model was constructed and tested to evaluate the feasibility of hydraulically hoisting a coal-water slurry in a U-tube pipeline from the mine level to the surface with the assistance of compressed air. A prototype screw feeder is used to continuously compact and inject 5-cm or less run-of-mine coal into a pressurized 20-cm-diam pipeline. Production rates up to 40 metric tph at an airflow of 1.5 m3/min were achieved with the model, and coal size degradation was relatively minor. Modifications are in progress to achieve 100 tph at an airflow of 2.8 standard m3/min injected into the riser pipe. Pilot-scale results indicate that an air-lift hydrohoist system is a feasible, cost-effective alternative to conventional skip hoisting that can be installed in existing shafts or surface-drilled holes closer to the face area. Air-lift hydrohoisting offers advantages of infinitely adjustable slurry flow rates, reduced pressure at the point of coal injection, and flexible design that can be combined with hydraulic pumping. Proposed design changes are discussed for coal transport, mine layouts, ventilation, fire control, and escapeways using this system.

Jan 1, 1995