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By J. R. Schafler, J. L. Brinkman

"Since the year 2000, 59 miners have lost their lives to explosions occurring in underground coal mines in the US. More accurately, those explosions were methane ignitions that propagated through the mines due to coal dust involvement; despite current explosion prevention standards. There are 4 basic strategies employed to manage the risk of coal dust explosions in many other coal mining countries around the world: removal of the coal dust, wetting of the coal dust to prevent it from becoming airborne, mixing of the coal dust with stone dust to increase the total incombustible content, and explosion activated barriers which make the entire roadway inert. However, American standards only mandate the first 3 of these 4 methods. It is possible that US coal mine safety measures could benefit from the implementation of the 4th method, the use of explosion barriers. This paper will discuss differences/similarities in barrier regulations used in other countries, as well as some potential difficulties with adapting a stone dust bag barrier system to US underground coal mines. Also, details and feedback gathered from two operating mine site trial barrier installations will be shared.INTRODUCTION Since the year 2000, 59 miners have lost their lives to explosions occurring in underground coal mines in the United States (US); 29 miners were killed at the Upper Big Branch mine in 2010, 5 at the Darby Mine No. 1 in 2006, 12 at the Sago Mine also in 2006, and 13 at the Jim Walter No. 5 Mine in 2001.[14] To be more accurate, the explosions that killed those miners were methane ignitions that propagated through the mines due to coal dust involvement.[18, 19, 20, 21] These deaths occurred despite current explosion prevention strategies, standards, and regulatory oversight. This poses the question, can more be done in the US to prevent coal dust explosions and their widespread damage. In review of current practices and regulations from several large coal mining countries, a disparity in prevention strategies arose. The main difference between the US and other countries was that the US does not encourage, mandate, or regulate the use of explosion barrier systems as an additional coal dust explosion mitigation measure. This raised many questions. First and foremost was whether or not the US coal mining industry and its miners could benefit, in terms of safety and fatality prevention, from the implementation of the explosion barrier systems that are used in other countries. Furthermore, are there significant differences between the coal mines in countries where explosion barriers are used and US coal mines, which would preclude the system from being adapted and implemented in the US? Also, what are the similarities and differences in explosion barrier systems, use, and regulations between other countries that use them?"

Jan 1, 2017

By Gerald P. Kelton

Over the past quarter of a century, the success of the hydrocyclone as a classifier in closed circuit grinding installations has permitted the introduction of the cyclone into virtually all fields of wet industrial processing. Research and experience gained in these applications have established the optimum cyclone sizes and designs necessary to provide the required performance. Although cyclones are used in widely diverse liquid-solid applications, their use for ultrafine separation clearly demonstrates the importance of a familiarity with previous case studies. Krebs Engineers is firmly dedicated to serving the process industry and has acquired the unsurpassed knowledge and experience to handle all types of separations and classification problems. Cyclones have been used for a number of applications to make what might be considered fine separations. A typical example is in an iron ore grinding circuit where a 381 mm diameter cyclone will classify an overflow product to 85% -44 micron. There is no question that this is a fine separation, but still finer separations are possible, and these are known as ultrafine separations.

Jan 1, 1983

An incremental analysis based stope design optimization method was developed at Exodus, an underground project located 30 miles north of Carlin, Nevada. Traditional underground stope design methods, by manually drawing stope shapes, are typically very time-consuming and lacking of consistency and accuracy. For quick reserve calculation and economic analysis, a new method named '3D Incremental Analysis based Stope Optimization' was created for mine wide stope designs at Exodus. With this unique but practical method, multiple options of mine designs were completed within a short period time, which allowed us to select the optimal cutoff grade and best stope design option for the project.

Jan 1, 2012

By W. A. Hockings

This report describes a computer program for the solution of material balances in complex mineral processing flowsheets. The program, which is entitled MBS Metallurgical Balance System), evolved as the culmination of a series of material balance programs whose development began in 1967 at the Institute of Mineral Research, Michigan Technological University. The need for such a program became evident when the Institute became heavily involved in a large number of short-term pilot plant projects. Calculating material flows from analytical data by means of the standard two-product formulas grew increasingly difficult and time-consuming as the complexity of the flowsheets increased and as choices between conflicting analytical values had to be made. It was recognized that what was needed was a program that would assimilate all of the available data and calculate mass flow rates so that steady-state inputs and outputs would balance at each point in the flowsheet. Such a program should be capable of handling underdetermined, overdetermined and mixed systems, and when the given data are inconsistent, the program should adjust the data in such a manner that the adjustments are minimized. Missing analyses should also be calculated whenever possible. In addition to solving material balances, the program should be convenient to use and print out the results in a useful form. Thus, the inputting of data should be simple enough to be handled by relatively untrained personnel with diagnostic messages being printed out to identify errors and anamolous data when they occur. Most importantly, the program should produce well-formatted output which can be directly included into a report without the necessity of retyping. The proper spacing of table titles, column headings and the ability to control the columns being printed are important features in this respect.

Jan 1, 1977

By R. S. Olsen

Intensely altered rock has had a large effect on slope stability as slopes increase in height at Island Copper mine. Traditionally used, fracture-controlled rock slope stability design techniques have been supplemented with analyses of failure modes which include failure along curved surfaces typical of soil materials. A rock mass rating (Pa) system has been developed that addresses the lower end of rock mass strengths. Rock masses are rated in terms of fabric integrity, alteration, fracturing intensity and gouge strength. Rock mass classes have been defined using statistical frequency distributions of rock mass rating values. Strength values have been assigned to the various classes from shear testing, back analyses of failures and engineering judgment.

Jan 1, 1987

By Robert M. Dreyer

In an industrialized nation, as the process of industrialization continues, the ratio of the value of production of non-metallic to metallic minerals normally increases gradually over a period of years. For example, in the United States, the ratio of the value of production of non-metals to metals now is approximately two-to-one. Those of us who come from California like to think that we inherit the mantle of the old hard-rock miner, but the truth of the matter is that, in California, of the total value of mineral production exclusive of fuels, 97% comes from non-metallic - industrial - minerals. Since the industrial minerals furnish a principal source of raw materials for the construction and chemical processing industries and since these two industries, in industrialized nations, generally increase directly with increasing population, the future of industrial mineral production both in the United States and throughout the world is indeed bright. Because of the importance of industrial mineral production, it often surprises those of us in the industrial mineral industry to find that industrial minerals are poorly understood by many of our colleagues in the mining industry. I think that one reason for this comprehension of the industrial mineral industry is that the education of both geologists and mining engineers still markedly emphasizes exploitation of the metals.

Jan 1, 1964

By Donald J. Reining

The California Surface Mining and Reclamation Act (SMARA) is the nation's first legislation establishing a statewide mineral resource policy governing mining activities that recognizes regional needs and retains local autonomy. The Southern California Rock Products Association supported this proposed legislation. It was through our efforts that SMARA was passed in 1975. The local planning and zoning processes, which are so critical to the mining industry, have been significantly improved with implementation of SMARA. Recognition of the importance of the mining industry is now being developed by the State Mining and Geology Board and the California Division of Mines and Geology (CDMG).

Jan 1, 1984

By C. I. Basilio

Pearson's hard and soft acid and base (HSAB) principle may be applied to flotation systems. The HSAB principle states that hard acids prefer to bond with hard bases and soft acids prefer to bond with soft bases. By determining the Drago E and C parameters for the different components of a flotation system, the HSAB principle could be used to explain the selectivity of some collectors such as thionocarbamates against some minerals. Determination of these parameters is done by utilizing Drago's theory and flow micro-calorimetry.

Jan 1, 1991

By A. Martikainen, S. GYAMFI

Luossavaara-Kiirunavaara Aktiebolag’s (LKAB) Konsuln iron ore mine, located just south of the famous Kiruna iron ore mine in Malmfälten in northern Sweden inside the Arctic Circle, was developed as a test mine between 2018 and 2020 for the Sustainable Underground Mining (SUM) project [1]. Besides functioning as a test mine, Konsuln also contributes to ore production. The existing mine ventilation system was designed for the current production rate of 0.8 Mtpa using conventional diesel machines. The design was created by Kiruna mine ventilation team, Stina Klemo and Joakim Jonasson, in cooperation with a consultant, Tomas Bolsöy from EOL Vent Mining AB. There is a plan to increase this rate to between 1.8 and 3 Mtpa in the future, and this requires the primary fans to be upgraded. Therefore, a study was carried out to determine whether using ventilation on demand (VOD) could avoid this fan upgrade and reduce Konsuln’s ventilation and heating power costs in the future. The study also investigated whether using battery electric vehicles (BEVs) along with VOD or as a standalone strategy could further reduce these power costs. In addition, the study analyzed the suitability of heating power reduction strategies presently or previously used in Nordic countries and Canada to investigate potential additional strategies to reduce heating power cost, the largest portion of Konsuln’s ventilation and heating power costs.

By Lianhui Jia, Yali Han

"The key technologies of a large rectangular pipe jacking machine with dimensions of 10.12m × 7.27m (width x height) include selection of rectangular cross-section cutting modes, analysis on the strength and stiffness of the rectangular shield, integrated control of electro-hydraulic proportional thrust systems and ground conditioning for excavation are presented in detail in this paper. These key technologies have been successfully applied and verified on site during tunneling, providing a new concept for the building of large rectangular traffic and pedestrian tunnels in urban areas for the future.1 INTRODUCTIONIn the past, underground tunnels were mainly used for drainage, sewage, utilities, metro tunnel, etc. and most of them had circular cross-sections. Recently, as a result of economic development, gradually accelerating urbanization process and diminishing ground space, underground tunnels have already become a new trend for urban underground space utilization. Due to the heavy traffic flow, the demands for rectangular cross-section underground tunnels, such as pedestrian underpass and road tunnel, are increasing gradually.The Rectangular pipe jacking machine (hereinafter referred to as RPJM) was firstly developed in Japan for the construction of metro station, pedestrian underpass, underwater tunnel by-passes, etc. Kazunaki Kawai et al. introduced a RPJM developed and manufactured by KOMATSU in 2002 [1]. Tosikazu Kubota et al. confirmed the rectangular tunnels’ superiority to circular tunnels with regard to larger inner cross-section and lower construction cost in their RPJM construction reports [2]. Compared to circular pipe jacking machines, a RPJM also has the merits of a higher inner tunnel space utilization ratio and is able to excavate in shallow overburden areas. As shown in Figure 1, the effective area of a rectangular tunnel is more than 20% higher than that of an equivalent circular tunnel."

Jan 1, 2016

By A. H. Srnallbone

Over the past few years the rising production costs, shortage of skilled labor, and increased use of lower grade ore bodies have all added justification for the use of on-stream analysis. A rise in the number of on-stream units indicates that this type of assay is now being accepted as a necessity. On-stream analysis is a much more rapid means of obtaining true assays of a flowing product when compared to wet chemistry or "grab" samples dried, briquetted and assayed by x-ray. In contrast, on-stream analysis uses real time samples assayed every 30 seconds while each stream is assayed every 5 to 15 minutes. It is very important not only to know that a change has occurred in the process, but to know what caused the change and how to correct for the change. For example, in a tailing sample the elements of interest comprise between 1% and 10% of the sample. The remainder is water and gangue. Previously the gangue was not assayed nor were the low atomic number elements used for corrections. In addition to the demand for higher accuracies some concentrators were being penalized for excessive Ca or in some cases 5i in their concentrates. This penalty was being imposed by the smelter in order that they could better cope with pollution problems and prolong the life of their furnaces. But until Ca, 5i, and S are measured on-line, nothing can be done about their control. By accurately measuring these light elements on-line, a complete assay is obtained of the total sample providing improved accuracy for the important products. The justification for complete accuracy assays is now even more obvious because they are possible at very 1ittle increased cost and at no increase in analytical time.

Jan 1, 1977

By Faruk Oksuz, Dave Schiemann, Matt Trotter, Mike Padilla, Carmen Scalise, Miquel Sanchez

"The McCook Main Tunnel system consists of a 10-m (33-ft) finished diameter, 490-m (1,600-ft) long, hard rock tunnel constructed from a 27.5-m (90- ft) diameter and 92-m (300-ft) deep main gate and tunnel construction access shaft. The gate shaft houses six, high-head 4.4 m by 9 m (14.5 ft by 29.5 ft) wheel gates to be installed in the bifurcated and steellined section of the tunnel. The tunnel also includes portal and energy dissipation structures as it daylights into the reservoir.The construction of the tunnel system has been divided into two contracts. The gate and construction access shaft was completed in August 2011. The tunnel excavation and concrete and steel lining was completed in September 2014. The remaining and undergoing construction include the tunnel connections to the reservoir and the Mainstream Tunnel and installation of gates and hydraulic cylinders. This article focuses on the live connection of the McCook Main Tunnel to the Mainstream Tunnel that was initiated in November 2014 and will continue through the seasonal drier weather conditions in Chicago approximately from October through April. Chicago TARP systemThe MWRD has been addressing combined sewer overflows (CSO) and flooding in Chicagoland since the late 1960s and formally adopted the tunnel and reservoir plan in 1972 to protect the region’s most precious drinking water supply, Lake Michigan. Phase I of TARP, which included construction of 175 km (109 miles) of deep storage and conveyance tunnels with diameters up to 10 m (33 ft), was completed in 2006. In addition to protection of Lake Michigan from CSO discharges, Phase I resulted in substantial improvements in surface water quality as well as the quality of life for lake and riverfront communities in Chicago. Water quality improvements and flooding mitigation will be further enhanced as Phase II reservoirs are placed in service, including the three large reservoir systems, McCook, Thornton and Majewski (Fig. 1).The McCook Reservoir is the largest reservoir in the TARP system. Once completed, this $700-million reservoir facility will receive 38 billion L (10 billion gal) of CSO and flood water via the McCook Main Tunnel, which connects the TARP Mainstream Tunnel to the McCook Reservoir, and from distribution and Des Plaines inflow tunnels which will bring flow from the Des Plaines Tunnel of TARP."

Sep 1, 2016

By L. K. Holder

"The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), commonly known as Superfund, mandates evaluation of remediation alternative using nine criteria: (1) overall protection of human health and the environment, (2) compliance with ARARs (applicable or relevant and appropriate standards), (3) long-term effectiveness and permanence, (4) reduction of toxicity, mobility or volume, (5) short-term effectiveness, (6) implementability, (7) cost, (8) state acceptance, and (9) community acceptance. Many states have adopted these or similar criteria for remedy selection under state laws. Although not explicitly addressed in the CERCLA criteria, consideration of sustainability can be incorporated into these criteria. This paper explores how sustainability can be evaluated for remedy selection using the CERCLA criteria. INTRODUCTION Sustainability considerations can be incorporated into all phases of site remediation: • Site investigation (remedial investigation). • Remedy selection. • Remedial design. • Remediation construction. • Operations, maintenance, and monitoring. This paper focuses on remedy selection. Many have looked at remedy selection using sustainability criteria. However, CERCLA and corresponding State programs require remedy selection using mandatory criteria. This paper shows how sustainability can be explicitly considered using the mandatory criteria. REVIEW OF CERCLA CRITERIA First, we review the definitions of the CERCLA criteria. We then explore how sustainability criteria can be fit into the CERCLA criteria. Overall Protection of Human Health and the Environment This criterion addresses the degree to which each alternative is protective of human health and the environment, considering both long-term and short-term risks. Overall protectiveness is a ""threshold"" criterion, in that alternatives that do not achieve adequate protection of human health or the environment are eliminated from further consideration. Evaluation of this criterion is derived from the evaluation of the other criteria (e.g., long-term effectiveness and permanence, and short-term effectiveness). It is not an independent criterion, but more a summary of the overall evaluation."

Jan 1, 2015

By A. A. Sobek

Controlled release systems delivering the required concentration of an effective bactericide over an extended time period have been developed by The BFGoodrich Company's ProMac® Systems group. The ProMac system is site-specific and includes a four-step approach to controlling acid mine drainage (AMD): (1) Diagnosing the problem, (2) Prescribing the treatment, (3) Supervising the application of controlled release bactericides, and (4) Honitoring the success of applied treatment. The success of the ProMac system is evidenced by improved water quality, healthy vegetation, a reduction in levels of acidophilic thiobacillus, and a corresponding increase in population of beneficial microorganisms.

Jan 1, 1986

By James Warren Andrews

The values of saturated water vapor pressure from steam tables have been found to be inaccurate for mine ventilation usage because the effect of air on the saturated water vapor was disregarded. Presented here are the newest and most accurate currently available tables from the National Bureau of Standards (NBS). Also included are: (1) a formula for correcting the saturated water vapor pressure for temperature and altitude. (2) a formula for computing unsaturated water vapor pressure, and (3) a formula for air density. Because Systeme International (SI) units are used in the formulas, conversions are given from U. S. conventional units to SI units. The intent of this paper is to show by means of six steps the accurate calculation of mine air density for use on modern computers.

Jan 1, 1989

By T. Valentine

The SX-EW operation at Morenci includes three electrowinning tankhouses. Stainless cathode blanks require the use of insulating plastic edge strips, which typically have a service life of 1-2 years, therefore, regular replacement of edge strips is a fact of life in tankhouse operations. The largest tankhouse, Central, converted from starter sheets to stainless steel cathode blanks in 1999. During the first year of stainless blank operation at Central Tankhouse, the initial installation edge strips started failing at accelerated rates and there was a sudden need to replace edge strips and repair between 350 and 400 cathode blanks per day. This paper details the design and building of cathode repair shops at the Morenci tankhouses, including choice of equipment and layout design. The objective was to increase efficiency through the use of cathode handling equipment and flow of material.

Jan 1, 2002

By R. E. Hamilton

Automation is a word whose meaning has been broadened by popular usage to include any labor saving device. We with restrict our usage to the replacement of human judgement by instrumental measurement and mathematical analysis in the control of industrial processes. Mineral concentration is an area which has resisted automation because of the great difficulty in developing measuring instruments which can exist in the rugged environment and can measure useful properties with acceptable accuracy. This is not the only factor limiting progress, but until recently it has been of over-whelming importance. The development of on-stream X-ray analysers, magnetic flowmeters and nuclear density meters for mineral slurries has eliminated this obvious barrier and is enabling us to locate and attack the less obvious problems which still limit our ability to automate concentrators. If we examine the history of automation in industries which are highly automated we find that it has usually gone through three distinct phases. The first phase has been regulation. This is the simplest form of control and involves manipulating some variable whose value is of no importance in order to maintain the value of some other variable which is important at a constant specified value in spite of disturbances which may occur in other variables which affect it. A simple example is the use of a control valve to maintain a constant flow of fluid in a line in spite of changes in pressure in the vessels at the ends of the line. The position of the valve stem is of no consequence, as long as it is within its operating range. Unfortunately we soon run out of variables which can be

Jan 1, 1971

By P. Mousset-Jones

The USBH Mining Systems and Ground Control Generic Research Center funded a project leading to the improved planning of airflow and refrigeration in underground mines experiencing hot working conditions. The project was broken down into approximately five phases: 1. Visiting some of the known hot mines in the U.S. and sending out a questionnaire to determine other mines which might be experiencing hot working conditions in the future. 2. Choosing two mines in which to conduct measurements to determine the insitu rock thermal conductivity and diffusivity, and comparing these values with laboratory determined values. 3. Investigating computer programs available for mine climate simulation, and testing these programs with case study examples from the two mines where the rock thermal properties were measured. 4. Considering improved ways of estimating the wetness factor and experimenting with the use of heat flux meters to more directly measure the rock heat inflow into the airstream. 5. Applying the results of these investigations to simulating the climate for future mine development and production areas at the two- mines. The project is approximately two thirds completed. At the time of writing, the insitu measurements at one of the mines are still being recorded. This paper will be describing the procedures and results of the insitu rock thermal property measurements, and give a brief description of some of the simulated results obtained for a mechanised cut and fill stope case study from the Homestake Gold Hine in South Dakota.

Jan 1, 1985

By Joe M. Bryan, George E. Rodger

The development of small precious metal mines in the western states has been directed at heap leach operations. Crushing plants are an essential adjunct to heap leach operations. They must meet environmental air quality regulations which generally follow a similar pattern from state to state. Prior to mine construction a permit must be obtained and an operating permit granted during or shortly after the start-up period. The typical construction permit application consists primarily of drawings, specifications and an explanation sufficient to indicate that the mass of particulate matter entering the atmosphere is below minimum standards. The operating permit may be granted following demonstrations that air emission control equipment or methods comply with information submitted in the construction permit application.

Jan 1, 1987

By Ashis Bhattacherjee, Rahul Upadhyay, Nearkasen Chau, Aditya Kumar Patra, Dhanjee Kumar Chaudhary

Heavy earth-moving machineries used in open-pit mines intensively expose the drill operators to whole-body vibration and shocks and thus to musculoskeletal disorders. The roles of an individual, machine, and rock-related factors in their exposure remain poorly understood. This cross-sectional study investigated their role among 39 drill operators from Indian iron ore mines. It shows that 70% of the operators were exposed to high levels of vibration, above the limit values recommended by ISO 2631-1. Multiple linear regression models showed that the whole-body vibration and shock exposures were strongly associated with operator’s age, drill machine model, rock’s hardness, uniaxial compressive strength, and density. The role of body mass index was close to significance (p = 0.08). Univariate analyses found that drill’s age, seat pad thickness, and seat backrest height were also strong predictors. These results help in identifying risky operators, materials and occupational situations, and in implementing appropriate prevention and intervention to reduce and monitor the exposures and health risk.