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By J. G. Groppo

The Andritz Ruthner Inc. hyperbaric filter was evaluated at a pilot scale for dewatering fine coal cleaned by froth flotation. The pilot scale dewatering testing was conducted at a solid feed rate ranging from 100 lbs to 200 lbs/hr-ft2. Effect of hyperbaric operating parameters and addition of various surfactants and flocculants were evaluated on dewatering of fine coal. The tests data indicated that for the minus 100 mesh and minus 28 mesh clean coal product, the Andritz hyperbaric unit provided filter cake containing 23 percent and 14 percent moisture, respectively.

Jan 1, 1996

By Peter C. Badgley

Three tectonic provinces within the Cordilleran System, are analyzed in terms of tectonic framework. (1) Precambrian terrain of North-Central Colorado; (2) The Pacific Northwest; and (3) The San Andreas-Garlock fault system and associated features. In each case a close relation- ship is seen to exist between: (I) Arcuate mountain development; (2) Precambrian basement fabric; (3) Major fault patterns; and (4) Major mineral occurrences. The arcuate trends developed when the basement was still mobile. Later competent deformation rejuvenated pre-existing lines of weakness. Because of the pre-existing arcuate framework, the rejuvenated faults frequently act as conjugate shears (strike-slip faults) flanking the old arcs. The conjugate shears intersect to form wedge- shaped plates. When such plates move forward along boundary strike-slip faults in response to post basement orogenic forces, new secondary fracture systems are generated in the country rock flanking the advancing wedge. The apex regions of the wedges are particularly favorable for detailed exploration.

Jan 1, 1959

By X. Xie

The dissolution behavior of palladium powder in thiourea solutions has been studied. The variables studied included temperature, stirring speed, and concentrations of thiourea, acid and ferric ion. Palladium was found to be soluble in thiourea solutions in the presence of an oxidant such as ferric ion. The dissolution of palladium in thiourea solutions was found to be chemical reaction controlled with an apparent activation energy of about 2S.3 kJ/mol.

Jan 1, 1995

By Michael Markels

The United States Environmental Protection Agency (EPA) is charged under the Federal Water Pollution Control Act Amendments of 1972 with establishing effluent limitations which must be achieved by point sources of discharge into the navigable water of the United States. Section 301 (b) of the Act requires the achievement by not later than July 1, 1977, of effluent limitations for point sources, other than publicly owned treatment works, which are based on the application of the best practicable control technology currently available as defined by the Administrator pursuant to Section 304(b) of the Act. Section 301(b) also requires the achievement by not later than July 1, 1983, of effluent limitations for point sources, other than publicly owned treatment works which are based on the application of the best available technology economically achievable which will result in reasonable further progress toward the national goal of eliminating the discharge of all pollutants, as determined in accordance with regulations issued by the Administrator pursuant to Section 304(b) to the Act. Section 306 of the Act requires the achievement by new sources of a Federal standard of performance providing for the control of the discharge of pollutants which reflects the greatest degree of effluent reduction which the Administrator determines to be achievable through the application of the best available demonstrated control technology, processes, operating methods, or other alternatives, including, where practicable, a standard permitting no discharge of pollutants.

Jan 1, 1975

By Pascal Deschamps

"INTRODUCTION During the last decades, many underground facilities for the storage of hydrocarbons have been excavated worldwide and the technology is fully mature. Similarly to other underground structures, the initial basic design has to be adapted along with the work progress, in order to cope with the actual site conditions and in particular the geology, hydrogeology and associated rockmass quality. In addition, Client’s or underground Contractor’s constraints (such as resources availability, schedule or cost impact) may vary from design to construction and require last minute adjustments. Engineers are required to introduce flexibility and anticipation of unexpected situations (similar to the above-mentioned) while conceiving large underground facilities. Although most of the cases require only minor adaptations, crucial parts of the facility have sometimes to be considerably modified and reviewed. This article will present four cases evidencing how the design of one of these essential structures - the concrete plug – has been adjusted during site implementation without impairing the initial performances. Hydrodynamic containment The product containment of the unlined caverns discussed here is ensured by the principle of hydrodynamic containment. A permanent water flow is naturally or artificially maintained with an orientation toward the storage cavern and then, neither product-tight membrane nor lining are required. The hydraulic gradient (and the associated water flow lines), being directed from the surrounding mass toward the cavern, prevent from outward migration of the product. If the hydraulic gradient is not sufficient or if the water table is evidencing instability, water can be artificially injected into the rockmass through purpose-built boreholes, drilled from dedicated galleries. This water injection system, called the water curtain, is generally located several tens of meters above the level of the cavern. This principle is illustrated here after."

Jan 1, 2016

By R. E. MacDougall

Very few mineral properties spend their entire lifespans from discovery to depletion in the hands of one owner. More likely, properties will have several owners, and partial interests may change quite often. Similarly, mineral companies are bought and sold with frequency, in recent years at what appears to be an accelerating rate. The reasons for selling a property can be manifold -need for additional capital in other parts of the business, need for development capital, realization of a large gain at a perceived high point in the market, pessimistic commodity outlook, retirement of principals, or resolution of estate problems. Regardless of the reasons for a sale, there are specific steps that logically follow. Spruce up the business, package the information, market the property, negotiate the terms, close the sale, and make sure it stays sold. Adherence to certain very basic ground rules in property sales can maximize the profits and minimize the effort.

Jan 1, 1990

By Gy. Deák Deák

The ECOMINING platform aims to develop a scientific and technical organization in order to promote within the natural resources industry a framework for environment-friendly exploitation technologies (on Best Available Technologies principle) and also to develop a solid basis for performing Research and Development projects. The ground of this project is the success of the First International Seminar: ECOMIN-ING - Europe in 21st Century1, organized by the Research and Development National Institute for Metals and Radioactive Resources Bucharest in co-operation with ITASCA Consultants GmbH Germany, the University of Petrosani and supported by the National Society of Salt Bucharest & Praid salt mine branch and the Ministry of Economy and Commerce. The platform provides a complex data base, for partners? selection and researchers? team structure. This can provide the scientific results with a high level of confidence for the projects of interest in the field of exploitation of mineral resources and for the participation on national and international project proposals competitions (i.e., target the 7th Framework Programme or any European / national programme, which can provide funds for the ECOMINING platform field of interest). The next step is the affiliation of the ECOMINING platform to the European ones, and to be compatible with them. The ECOMINING platform represents itself a 7th Framework Programme (FP) project idea.

Jan 1, 2007

By M. R. Shahan, W. R. Reed

A laboratory apparatus (shield dust simulator) was designed and constructed to simulate the dust generated during the advance of longwall hydraulic roof supports, or shields. The objective of the study was to develop a tool that could be used to test the hypothesis that foam applied to a mine roof prior to a shield advance could be used to reduce the respirable dust generated during shield advances. This paper will outline the design parameters for the development of the system, as well as describe baseline testing of coal and limestone dust. Results show the average instantaneous respirable dust concentrations that occurred during simulated shield advance. Confidence intervals were calculated from the instantaneous respirable dust data to determine the repeatability of the data produced by the device. INTRODUCTION During longwall mining, miners can be exposed to respirable dust that is generated during the advance of hydraulic roof supports or shields. National Institute for Occupational Safety and Health (NIOSH) researchers have conducted numerous surveys of longwall mining operations, benchmarking the operating practices and dust control measures in use. It has been determined that the shields are responsible for 27% of the respirable dust that is generated on the longwall face [1]. The dust generated by the shield advances ranks second, next to the longwall shearer which is accountable for 43% of the respirable dust generated on the longwall face. The respirable dust generated during the advance of the shields can be a significant contributor to the respirable dust exposure of the mining personnel operating at the longwall face, especially since some of this dust is generated in the walkway. Control systems designed to reduce the dust levels generated during the shield advance have the potential to greatly reduce the respirable dust exposures of the personnel downwind of these activities. One control technology to decrease the dust generated by the shield advances would be to apply a layer of foam to the forward shield-roof interface prior to the shield advance [2]. The blanketed layer of foam would interact with the material located on the top of the shield during the advance, preventing a portion of that dust from becoming entrained in the mine air. This layer of foam would be applied using a foaming nozzle located on the longwall shearer body that would spray foam on the roof surface as the shearer passed. Substantial laboratory work has been completed to determine the feasibility of this type of foam application. NIOSH engineers have classified the various characteristics of foaming agents, using foam expansion ratio and drainage as important properties, as well as developed the mechanical systems required to apply the foam safely to the mine roof [2, 3]. The construction of an apparatus that could simulate the mechanical interaction between the dust-laden shield top and mine roof was necessary to adequately test the hypothesis that foam could be an appropriate control. A team of engineers designed and constructed a shield dust simulator system allowing for in-house testing prior to a full-scale field investigation.

Jan 1, 2019

By C. Bateman, F. Calizaya

"This study presents the results of three laboratory experiments on pressure balancing carried out at the University of Utah’s coal mine ventilation model. The model includes simulations of two working areas, one longwall mine gob, and a set of stoppings and seals. It also includes a pressure chamber between the longwall face and the gob. The model is ventilated by one main fan and one bleeder fan. A carbon dioxide injection system, equipped with flow control valves operated by a microprocessor, is used to pressurize the chamber and to maintain the pressure in the chamber slightly higher than that of the gob. During each experiment, fan pressures and stopping resistances were changed, the carbon dioxide injection rate was regulated, and the differential pressures across the stoppings were monitored so that the chamber pressure is always kept slightly higher than that the gob pressure. Result of these experiments are reported in this paper. INTRODUCTION Spontaneous combustion (Sponcom) is a safety hazard in underground coal mines. The history of coal mining in the US is replete with mine fires and explosions. Sponcpm accounts for approximately 17% of the total number of fires recorded in the U.S. since 1990. In the U.S., by law, worked out areas in coal mines must be either ventilated by a bleeder system or isolated by explosion proof seals. Experience has shown that seals are not airtight structures and that they allow some leakage of air into or out of the gob. In fact, seals “breathe in and breathe out” with changes in barometric pressure (Francart 1997, and Chalmers 2010). These changes in pressure affect not only the methane emission rate but also the ingress of oxygen to the gob, the lower the pressure behind seals is, the higher the ingress of oxygen. In mines ventilated by a U-tube exhaust system, the gob is often kept under negative pressure. Under these circumstances, an increase in barometric pressure may cause an influx of fresh air into the gob. This quantity may be sufficient to start self-heating of the coal, which can lead to spontaneous combustion. Depending on the coal characteristics and the ventilation conditions, self-heating of coal can start at temperatures as low as 35 ºC. If the heat is not removed it will increase the coal temperature leading to ignition and fire. The risk of Sponcom fires can be reduced by isolating the mine gob using rated seals, and implementing a suitable ventilation system. However, isolation seals are not airtight structures, thus some leakage of air is expected unless the pressure in the gob is neutralized. The alternative is to use a pressure balancing system. This requires a thorough knowledge of the ventilation system, the seal/stopping construction techniques, the airflow behavior in the gob area, and the gas build-up behind the seal line."

Jan 1, 2016

By Charles A. Beasley

Increased technical and legislative analysis by all parties of interest could result in more efficientand better directed regulatory legislation in the mining industry. Efforts to forestall or frustrate legislation through massive lobbying and public relations efforts are seldom effective over time and often lead to more stringent and far reaching legislation than necessary. The Federal Coal Mine Health and Safety Act of 1969 is perhaps an outstanding example of such insufficiences; a future example may well be regulatory surface mine legislation. Although a lack of extensive hard data seldom enables rapid or sophisticated analysis early in the legislative process, even preliminary analysis may be sufficient. Simple statistical analyses of available data, assessment of the legislative rationale, and subjective appraisal of other non-quantifiable constraints to improved mine safety. An average of 115 underground fatalities at an exposure frequency rate of 0.67 can be reasonably expected in the immediate future, under existing levels of technology, degree of regulation, and economic conditions. If gross unrefined estimates of 6 preparation plant, 5 surface, and 30 strip mining fatalities are assumed, the total fatality industry level could be expected to approximate 156 Serious professional, economic, and technical constraints within the the industry probably preclude any major decrease of these accident levels within the near future

Jan 1, 1972

The impact of a methane explosion on mining operations cannot be over-emphasized. The explosion is a result of rapid combustion when a methane/air mixture is ignited by an unexpected energy release, such as a mine fire, electrical arc or sparks caused by frictions or rock falls. In most cases, an ignition of methane/air mixture could result in a deflagration other than detonation. Resulting flames and overpressure induced by a methane deflagration will harm neighboring miners and local ventilation control devices.. ,It is essential that the mechanism of an explosion and associated destructiveness be fully understood. This research seeks to predict an influence region of an incident happened within a representative underground mine geometry. The most common geometric changes in an underground coal mine are bends, regulators/doors, obstacle in airways and changes in sectional area. These geometric changes could result in an attenuation of the flame and pressure wave as a result of a methane deflagration. A study of this phenomenon could enable mine planners to have better understanding of the over-pressure redistribution due to the explosion. Both numerical and experimental work has been done in this study to ascertain a better insight of this potentially devastating event. The experimental data are also used to validate the turbulence and combustion models used in this test.

Feb 23, 2014

By Satoshi Honda, Mitsuru Shimizu, Tatsuji Nagao, Motoaki Kurisu, Hirokazu Izumi, Toshinori Takahashi, Hiroyuki Itoi

"1. INTRODUCTION Grade separation of roads and railway tracks is an effective method for solving traffic-related issues in cities. However, in urban areas where the existing traffic infrastructure is already overcrowded, construction of new roads often faces problems especially in the proximity of existing structures. This paper summarizes the construction plan and results of new road tunnel construction in the proximity of the piers of elevated tracks on the Tokaido Shinkansen railway.2. SUMMARY OF CONSTRUCTION AND ISSUES Auxiliary Route No. 26 as specified in the Tokyo urban plan is a project by the Tokyo Metropolitan Government, covering the construction of a new road with a total length of 22.3 km currently on the way to completion. In Shinagawa Ward, Tokyo, Auxiliary Route No. 26 is designed to cross the railway tracks of the Yokosuka Line and the Tokaido Shinkansen Line, so for this project, the East Japan Railway Company (JR East) was commissioned to design and build a road crossing under the railway tracks (Sumiyoshi Underpass). Figures 1 through 3 show a sketch of the Sumiyoshi Underpass. The Sumiyoshi Underpass was planned as a two-lane tunnel for vehicles, which was to cross under the railway tracks of the Yokosuka Line and the Tokaido Shinkansen Line at an angle of 70 degrees. The structure concerned is a single-story single-span box culvert structure with the following dimensions: 11.5 m wide, 7.7 m high and 31.6 m long. The Tokaido Shinkansen Line tracks were constructed on a girder-type elevated bridge built in the 1960s, and the foundation piles of the piers (P7 and P8) in the proximity of this crossing box culvert of RC structure were constructed using an earth drill method. The crossing structure for this project is located extremely close to the piers of the Tokaido Shinkansen railway tracks, with a minimal separation of 0.4 m, and the most significant issue of this project was construction in a manner that would not obstruct the normal operations of the Tokaido Shinkansen (Figure 4). Initially, we considered installing a temporary earth retaining structure in the proximity of the piers, cutting the ground and building an RC box, but concluded that it would be very difficult to apply this method because of probable excessive displacements in the Shinkansen railway piers. That is why we decided on the use of a non-open cut method in order to minimize the impact on the piers."

Jan 1, 2016

By Ronald J. Roman

A mathematical model was developed for the grinding and flotation section of Union Carbide's Bishop mill and this model was used to indicate how variations in grind, retention time, and calcite and fluorite content effects the mill capacity, tungsten units produced, and the grade and recovery of the scheelite concentrate. A model such as this is a starting point in determining the economic optimum running condition for a mining and milling operation and an example of this is given.

Jan 1, 1969

By R. M. G. S. Berezowsky

An atmospheric ammoniacal thiosulphate leach system was developed to recover gold and silver from residues of the ammoniacal oxidation leaching of sulphidic copper concentrates. Extractions of 88 - 95% Au and 83 - 98% Ag were attained within 2 to 4 hours at 40 - 60°C in thiosulphate leaching of the oxidation leach residues of Manitoba chalcopyrite concentrates analyzing 24.6% Cu, 0.18 oz/ton Au and 4.26 oz/ton Ag and a complex British Columbia chalcopyrite/tetrahedrite concentrate analyzing 18.5% Cu, 0.27 oz/ton Au and 276 oz/ton Ag. Parameters affecting the Au and Ag solubilization included thiosulphate, ammonia, and cupric ion concentrations, temperature, retention time and the degree of Cu extraction and sulphide oxidation in the primary oxidation leach. The precious metals were recovered from the thiosulphate liquors by zinc dust cementation.

Jan 1, 1979

By Clark D. Harrison

This paper compares the ash slagging potential of Illinois No. 6 Seam coal: as raw coal; as commercially cleaned coal processed in a baum-jig plant; and as coal cleaned to a reduced ash specification at the Electric Power Research Institute's Coal Cleaning Test Facility. The comparison is based on: ? ASTM ash fusibility data ? A slagging index ? Gravity fractionation analyses of critical mineral matter compounds ? Comparative pilot combustion tests. The first three grounds of comparison are laboratory data; and the final comparison involves burning approximately 15 tons of each coal at CONOCO's 1.5 MBtu/hr (440 KW) test combustor. The evidence of these .four comparisons indicates that lowering the ash specification of coal before combustion can significantly improve the ash slagging characteristics of Illinois 90. 6 Seam coal.

Jan 1, 1984

By B. Kyslinger

"In underground mining, machine design is predominantly dictated by mine conditions and individual customer desires. In partnership with Foresight Energy, J. H. Fletcher & Company was tasked to design and manufacture a new roof bolting machine with six independent drilling apparatus on board capable of drilling and bolting the roof and ribs with material handling. This is the first Fletcher® six head machine to be designed and built for the mines in the United States. The machine is intended to work in the Illinois Coal Basin. The objective was to produce a machine capable of drilling and installing six bolts simultaneously with a limited number of operators. The goal of the mine is to decrease the time to bolt a cut to improve the safety level of the current roof bolting method, improve efficiency and to improve the bottom line cost of entry development. The customer wanted four mast feed drills at the front of the machine dedicated to installing roof bolts and then another two mast feed drills behind them dedicated to rib bolts. This dictated the requirement of latched controls, which would allow the operator to start drilling one hole and then latch the controls to be able to move on to the next. To accomplish this, we developed a unique hydraulic latch circuit to maintain operator safety and compliance. Guarding was added to prevent an operator from coming into accidental contact with a latched drill. The result of the design is a machine with a single platform and six independent masts with drillheads: four masts strictly for drilling and installing roof bolts on the front of the platform and then two masts on the back of the platform for rib bolts. The feed and rotation controls at each operator’s station include a latch control for drilling. The latch control will allow the operator to lock in the feed and rotation once the hole has been collared, allowing the operator to move on to the next hole. The rear of the machine is equipped with material handling. There are two material pods with winch controls as well as a mesh rack that includes mesh lift, mesh tilt and mesh sump. The six-head roof bolter allows fewer operators to drill and install roof and rib bolts, which in turn lowers the miners’ roof exposure per cut. This design reduces the operator’s exposure from the inherent pinch points and rotary hazards once he has engaged the latch drilling. Therefore the machine will help to decrease the time to bolt a cut, improving productivity while enhancing the ability to operate the machine safely. INTRODUCTION When mining underground it is necessary to support the roof quickly to prevent it from collapsing after an area has been mined. Since the 1950s, the primary method for supporting the roof has been the installation of roof bolts. Roof bolting is one of the most basic functions yet one of the dangerous jobs in the underground mining operation (1). The Mine Safety and Health Administration’s (MSHA) Health and Safety Accident Classification injury database showed an average of 660 roof bolter operator accidents per year over a 5-year period (1999-2003) (2). The numbers show that roof bolting is the most hazardous machine-related job in underground mining. It represents 39 percent of all machine-related accidents in underground coal mines. In 1993, the U.S. Bureau of Mines conducted a study that has shown the activity of drilling as the most hazardous job task performed by a roof bolter operator, accounting for 31 percent of all roof bolting injuries (3). Almost half (46%) of these drilling injuries were due to falling rocks or coal from the roof. All of these injuries occurred under supported roof. The majority of these injuries (about 99%) are not caused by a major roof collapse but from falls of smaller rock from the immediate roof. This type of roof failure has also been termed “skin fall.”"

Jan 1, 2017

By Robert L. Runkel, Kenneth E. Bencala, Briant A. Kimball, Katherine Walton-Day

The solute-transport model OTIS and the reactive solute-transport model OTEQ were used to simulate geochemical conditions in Cement Creek, a tributary to the Anirnas River in Colorado. OTIS was used to depict instream zinc concentrations, and to simulate the effects of two remediation scenarios on zinc concentrations at the mouth of Cement Creek. These simulations do not account for effects of changing stream pH on metal concentrations. Preliminary simulations using OTEQ to account for instream pH changes were unsuccessful due to the spatial nature of mixing processes, and insufficient information about the thermodynamic properties of precipitates forming in mixing zones.

Jan 1, 2000

By Robert L. Major

The expanded role which coal has been assigned in the energy future of the United States has raised numerous policy questions. The very complexity of these questions makes them suitable to analysis by econometric models. However, as the Wall Street Journal indicated in its recent article, business' success with such models have been mixed. I have been asked to present my views as to how coal producers can use such models and in what ways the industry is likely to be impacted by such models. I do not presume to speak for the whole coal industry, but only to share with you the personal observations of one who has worked "both sides of the street", having been employed' both by government and a consulting firm prior to joining the coal industry. In my opinion, the use of econometric models to analyze the coal industry will impact the coal producers in two main ways. First, their use by government will have a profound impact on future government policies related to the mining, transportation and utilization of coal. Second, such models, when properly calibrated and refined, may become useful tools for the coal producers in doing market research and long-range planning. While the former has already begun to impact on the operating environment or the coal industry, the latter is still in the embryo stage.

Jan 1, 1977

By Paul H. Miller

After passage by the Congress, Public Law 95-87, the "Surface Mining Control and Reclamation Act of 1977" was signed by President Carter on August 3, 1977. This law, in its simplest form, was intended to control the environmental effects of surface coal mining and to ensure that mined land is restored to a condition equivalent to that prior to mining. Immediately after the signing, the wheels of government bureaucracy began turning to establish a new federal agency -the Office of Surface Mining Reclamation and Enforcement or OSM -in the Interior Department that would implement the provisions of the Act. Since this took time and because the Congress had not yet provided funding for OSM, a special task force was assembled within the Interior Department to begin the task of writing interim regulations to implement the Act. With respect to the use of explosives, the Act specified that a blasting plan be included in the application for a mining permit. The blasting plan will outline the procedures an operator will use to meet specified environmental protection performance standards. The performance standards established by the Act require explosives to be used only in accordance with existing state and federal laws and regulations and with regulations to be promulgated by the regulatory authority. The regulatory authority was defined as either a state agency operating under an approved state program or the OSM operating under a federal program. As a minimum, it was specified that the regulations should include provisions to require that: 1) a blasting schedule be published in a local newspaper and be mailed to local governments and to all residents living within 1/2 mile of the blasting site . 2) daily notice be given to residents in the area prior to blasting. 3) blast reports be prepared that are maintained for three years and available on request to the public. 4) blasts be designed to prevent injury to persons, damage to property outside the permit area, adverse impacts on underground mines and adverse effects on ground or surface water channels or availability outside the permit area. 5) upon request of residents or property owners within 1/2 mile of the permit area, preblast surveys shall

Jan 1, 1978

By Anna Eleria, Joseph Welna, Jim Herber, Nathan Campeau

Constructed by stonemasons over 120 years ago, a portion of the Trout Brook Storm Sewer Interceptor (TBI) owned and operated by the Capitol Region Watershed District in Saint Paul, Minnesota, needed rehabilitation. A routine inspection of the 10-foot limestone block tunnel revealed degraded and missing mortar between the blocks, allowing significant infiltration and soil migration through the tunnel joints. Conditions, including damaged and missing blocks, were considerably worse in a 250-foot-long segment beneath a busy mainline railroad corridor. Barr’s solution included tuck-pointing to repair the mortar joints, shotcrete overlay, and construction of a hybrid cast-in-place/shotcrete “tunnel within a tunnel” to support the mainline railroad loads.

Jun 13, 2021