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By V. J. Matta, A. A. Pincheira, I. A. Reghezza, Ch. J. Vergara

The growth of solvent extraction in Chile has been astonishing during the last years and has been established as a very successful technology. However, there are still limitations that must be improved, mainly, the problem of carry over from one phase to the other and the losses of organic reagent associated with the crud formation. These are problems that our company has been taking care, solving them with high efficiency and low costs, allowing important increases in the copper output of our plants and capital savings by means of the optimization of the use of nonproductive units in the SX plants.

Jan 1, 1998

By J. C. Mullen

Today, the coal mining industry is more knowledgeable on the potential negative economic consequences associated with improper management of hazardous substances and various types of solid waste. The practices evaluated during environ-mental audits are discussed and example situations are shared from previous audits of coal mines and analogous situations. The importance of assessing and understanding purchasing, warehousing, safety, maintenance, electrical, operations, and environmental management practices and procedures is highlighted as a key to a successful and practical program. A waste minimization approach is presented including strategies for screening product purchases, product substitutions, and testing and record keeping.

Jan 1, 1992

By C. C. Graham

In this paper, the problems which occurred on introduction of dense medium cyclone coal washing in Australia are reviewed together with the subsequent measures taken to obtain a satisfactory magnetite. Specification and testing of magnetite for exploration, quality control and in-plant check purposes is discussed. The disposition of Australian magnetite deposits in relation to the main coal producing areas is examined, and comments are made on the economics of mining, milling and beneficiating magnetite for coal preparation uses alone. Future trends in the Australian Coal Industry are predicted, and the need for a planned approach for the future is demons traced.

Jan 1, 1982

In this paper, the logic and the capabilities of a long term production planning method for open pit mining are presented. The method is the first attempt in obtaining simultaneous solutions to the four interrelated parameters of open pit mining; 1) the mine life, 2) the specific blocks to be mined each year, 3) the amount of ore and waste to be mined each year, and 4) the ultimate pit limits. An efficient cutoff grade can also be obtained through a sensitivity analysis. None of the existing methods can bring such a comprehensive solution to the problem. A production plan for a real life gold deposit is given to illustrate the logic and the capabilities of the method.

Jan 1, 1993

By Peter Zhang, Daniel Su, Mark Alexander Van Dyke, Heather Dougherty, Bo Hyun Kim

The National Institute for Occupational Safety and Health (NIOSH) has been evaluating longwall mining-induced strata fractures and their impacts on casing stability of Marcellus shale gas wells located in longwall pillars. To understand the extent of overburden fractures after longwall mining, NIOSH researchers drilled a post-mining corehole into the fractured strata above the Pittsburgh coal seam longwall gob. Knowing the extent of the fracture zone height will help gas operators minimize the hazards of drilling into longwall gobs. The core was retrieved from the surface down to the top of the gob void. Various fractures were encountered varying from 35 to 64°, depending on lithologic type and relative closeness to the gob. The longwall panel dimension was 457-m wide and 3657-m long, in which the total fracture zone height was found to be at 141 m and the hydraulic connected fracture zone at 87.7 m above the top of the Pittsburgh seam. In addition to core drilling through the gob, FLAC3D modeling was also used to simulate the formation of fracture zone and the orientations of longwall-induced fractures. This study provides much-needed evidence on the fracture zone of Pittsburgh seam longwall gobs to help gas operators avoid potential hazards associated with drilling through highly fractured zones in longwall gobs.

Jun 9, 2022

By A. Festa

Secondary crushing often gets good press for its increases in energy efficiency and SAG milling rates but for a project considering this option the proposed benefits soon get overshadowed by implementation concerns. Reverse engineering from the published case studies is risky unless the reader understands the drivers impacting stability and operability of the circuit. This paper discusses the features of secondary crushing for Greenfield and Brownfield SAG mill grinding circuits. It is the author?s view that secondary crushing rarely adds value to a Greenfield project and restricts future expansion. Its application is best retro fitted to Brownfield operations where the benefit gained for capital expended is excellent. Two case studies are presented to reaffirm these statements. The first case study shows that the implementation of partial and total secondary crushing increases SAG mill power efficiency and it offers substantial incremental increases in milling throughput with staged capital investments for the crushing and grinding circuits respectively. The paper provides a critical analysis of process conditions for secondary-crushed grinding circuits, with particular emphasis on Brownfield circuit retrofits. Furthermore, the second case study quantifies the economic impact of secondary crushing on circuit design for plant start up and it illustrates the limit imposed on plant expansion.

Feb 23, 2014

By R. Miller

Lowering our globe’s emissions is a major effort as we move toward a future net-zero carbon environment requiring significant investment in a new, low-carbon infrastructure, along with key market incentives to change. Industry will play a key part in this transformation, requiring expertise in both energy and emissions. Key elements of the de-carbonization strategy are: energy data, emissions reporting method, governance, de-carbonization project generation and drivers, the MACC, electrification, and the de-carbonization checklist. For a zero carbon future, it will be key for business leaders to understand decarbonization, anticipate technological changes, and implement new business me

Mar 2, 2022

By P. W. Conrad, C. Todd, N. A. Degerstrom, N. West, R. Kramer

"Surface subsidence caused by underground room-and-pillar mining operations and by solution mining operations have been studied separately but never in combination. In 2008, FMC Minerals began using solution mining at its Westvaco Mine as a secondary extraction method in an area that had been previously mined using the room-and-pillar mining method. Mining regulations require that subsidence associated with underground mining activities be monitored and measured annually. Using Salt_Subsid, a subsidence software package from the Solution Mining Research Institute, and ArcGIS, Esri's mapping platform, researchers at Montana Tech were able to develop a relationship between measured surface mine subsidence and solution mining that can be used at the Westvaco Mine to estimate the production of trona from solution mining operations. Project backgroundFMC Minerals has increased the production of trona from its Westvaco Mine near Green River, WY, using solution mining as a secondary extraction method in an area previously mined using the room-and-pillar method. The area of interest was mined until 2001 with the use of a borer miner at a depth of approximately 488 m (1,600 ft). Currently, FMC determines the amount of trona produced using its solution mining operations by measuring the dissolved solids pumped from the mine. This approach, however, does not account for the location from which the trona was removed.The location from which the trona is removed and the size of the cavern created by the solution mining operations are important to FMC’s mine planning. FMC believed that with proper investigation of the subsidence at the Westvaco test site, a correlation might be found between surface subsidence measurements and the amount and location of trona production from the solution mining activities. The primary goal of this project, conducted by Montana Tech, was to find relationships between the measured subsidence and the solution mining activities. The project attempted to develop an equation that could be used to predict solution trona production based on measured subsidence. The project attempted to model the relationship between the measured surface subsidence and solution mining production using Salt_Subsid, an existing subsidence software package from the Solution Mining Research Institute (SMRI, Clarks Summit, PA) to estimate the location, size and shape of the solution mining cavern. This study would determine the program’s usefulness for locating and developing the cavern created by secondary solution mining activities. The subsidence and production data sets used in this study were collected over a seven-year period from 2008 through 2014."

Jan 4, 2018

By G. Vijaya Kumar, B. Srinivasa Rao, G. V. Krishna Rao

The paper outlines the ventilation practices prevailing in coal mines of Singareni Collieries Company (South India). The high annual average surface temperature and relatively steep geothermic gradient results in virgin strata temperatures in the region of 38- 42°C creating environmental problems in the working places. Expensive methods of air cooling can not be employed as the mines are small, and production and productivity do not justify the costs of artificial cooling of mine air. Controlled recirculation of mine air -- the unconventional technique being tried with success in some coal mines in U.K. has been analysed for improving the environmental conditions. The analysis shows that the method is safe, cost effective and can be applied with very little extra equipment.

Jan 1, 1991

By A. W. Khair

This paper presents an engineering approach to solve a complex ground control problem at reduced cost, allowing the mine to be operated safely and economically. The mine has experienced serious and complicated cutter roof problem in the entries. This cutler roof problem has delayed the advance of the entry development considerably and cost of these entries is very high due to the requirement of very heavy artificial supports. The analysis includes assessment of the cause of cutter roof and step by step action taken to improve the entry condition through appropriate longwall panel entry design and roof support system. The approach for solving the problem was two-fold: 1) to apply yield pillar concept in order to reduce the effects of in-situ horizontal stress in the roof strata and 2) to find an effective way to reinforce the roof strata and to support the fractured roof and avoid caving.

Jan 1, 1990

By Robert R. Munro

Traditional aggregate sources, that is the riverbeds, the alluvial fans, located relatively close to the developing urban centers are being foreclosed to mining. As the sand and gravel reserves are depleted, those production plants are unable to secure additional adjacent reserves and are being forced to close down. The sand and gravel industry, in many respects, is its own worst enemy. We promote development, we promote the paving of streets, the building of houses, and industrial and commercial centers, and because of economics, we tend to favor those developments located close to our operations. Thus, we encourage development by our neighbors who soon become our detractors. In general, urban development is not compatible with sand and gravel mining. The neighbors don't like the view of the pits or the quarries, they complain about the "dust", about noise, about trucking . . . in general, the neighbors are not happy being close to an aggregate source.

Jan 1, 1984

By N. T. Rogers

An accepted statement of fact is that transportation next to agriculture is the second most important industry in the world. The transportation networks of the United States contributed immensely to the growth and prosperity of our nation. My objective is to make each and everyone here aware of the need for communication between geologists, mining engineers, purchasing agents and transportation managers. Only through a cooperative effort is it possible to reap the benefits of transportation in the industrial minerals field. Transportation is often thought of in terms of trucks, rail cars, barges, covered wagons or whatever. If this is your only exposure to the transportation industry then you probably spent most of your life in a cave.

Jan 1, 1989

By J. Diao

In order to understand the flotation kinetic behavior of coal and associated mineral matter, a detailed investigation was conducted in a 2-liter Denver flotation cell using three high sulfur coals at three feed sizes, minus 28. 100 and 200 mesh. Subsequently. the flotation products were sieved into different size fractions and analyzed for their ash and pyritic sulfur content in order to delineate the effect of particle size on the rate at which each constituent floats. The results were tested with several different flotation kinetic models and the best model for coal was then chosen. The flotation rate constant and the ultimate recovery calculated from a kinetic model were used to delineate the effect of particle size, collector (dodecane) and frother (MIBC) dosages on the flotation kinetics of coal, ash and pyrite.

Jan 1, 1992

By W. R. Reed, G. J. Joy, B. Kendall, A. Bailey

"Testing of the NIOSH-designed roof bolter canopy air curtain (CAC) has gone through many iterations demonstrating successful dust control performance under controlled conditions. J.H. Fletcher & Co. (Fletcher), an original equipment manufacturer of mining equipment, has further developed the CAC concept by incorporating it into the design of its roof bolting machines. A new CAC design has been developed incorporating the results of testing of the NIOSH design and the recent Fletcher design. Observations from smoke testing conducted on this new CAC design in a laboratory setting show promise for improved performance. INTRODUCTION Exposure to respirable coal mine dust can cause coal workers’ pneumoconiosis (CWP) otherwise known as black lung. If silica is present in the dust, the miner may develop silicosis in addition to CWP. CWP and silicosis are occupational respiratory diseases that are ultimately fatal and have no cure. The only method of prevention is through elimination of exposure to respirable coal mine dust and crystalline silica (quartz). The current occupational exposure limit (on an MRE basis) for respirable coal mine dust is 2.0 mg/m3 during each shift that a miner is exposed in the active workings of the mine or in mine facilities [30 CFR 70.100 2015]. Recently enacted legislation changes this standard beginning in August 2016 to 1.5 mg/m3 for a full working shift [Federal Register, 2014]. If the respirable coal mine dust contains more than 5% silica, the applicable respirable dust standard is reduced; calculated as 10 divided by the percent quartz present [30 CFR 70.101] so that the effective exposure limit for respirable quartz is 0.1 mg/m3 for a full working shift. Sources of exposure to respirable coal mine dust for the roof bolting occupations include infrequent maintenance and cleaning of the vacuum dust collection system and operating the bolter downwind (in the return air) of the continuous miner [Goodman and Organiscak, 2003]. Recent studies have demonstrated that vacuum dust collection systems are effective in capturing bolter-generated dust, if maintained and operated correctly and if proper face ventilation techniques are used. However, most exposure to respirable coal mine dust for the roof bolter occurs when the roof bolter machine is operated downwind of the continuous miner [Potts et al., 2011; Colinet et al., 2013]. Because of this higher exposure downwind of the continuous miner, the roof bolter is generally limited to working downwind of the miner only once during a production shift"

Jan 1, 2016

By J. M. Wempen

As development in underground coal mines progresses away from the critical components of the ventilation system, including the main fans and ventilation shafts, resistance within the system is markedly increased. This results in higher pressure and flow requirements from the main fan(s) to maintain adequate face ventilation. Upgrades to the primary ventilation system are often required. The use of booster fans underground is a potentially practical alternative to the addition of shafts and surface fans. This study presents simulations of the use of booster fans in two underground ventilation scenarios, one longwall and one room-and-pillar. The booster fan effects on the power requirements of the ventilation systems are evaluated.

Jan 1, 2011

By Donald L. Freed

Design, development, factory test, and in-mine evaluation plans are presented for an Automated Extraction System (AES) that has been designed to fill needs which are present in the Mining Industry. The philosophy of design and proposed operation of the machine, as well as the relationships between these factors, and final machine configuration are reviewed. The AES is designed to overcome production problems resulting from the regulation of roof control, clean-up, ventilation, dust suppression, and operator protection required by the Federal Coal Mine Health and Safety Act of 1969. The design permits more continuous operation and greatly improves operator safety. The machine is a full-face drum-type continuous miner which includes self-advancing, continuous temporary roof support. Onboard self-advancing face ventilation, dust suppression, and air scrubbing equipment are also included in the design. A further improvement over existing equipment is the incorporation of an automatic programmed cutting cycle control system. All mining functions including movements of the roof support system are handled by this automatic system.

Jan 1, 1977

By Richard C. Corson

Modern microprocessor systems make it possible to use several variables to anticipate changes in the process and to react with responses before upsets can be magnified by the process or by control action. Through tighter control, "insurance" can be eliminated from process set points without affecting product quality. In actual operation with a traveling grate furnace this control philosophy has produced savings of up to 20% in fuel consumption and 8% in fan power usage while producing a more consistent quality product.

Jan 1, 1982

Iran possesses very large copper resources, estimated to contain around 4-5% of the world's known copper inventory. There are several small private sector copper mining operating in the country, but Iran's copper industry is dominated by the state-owned National Iranian Copper Industries Company, which operates the world-class Sar-Cheshmeh open-pit Mine. This mine was developed in 1970s before the 1979 Islamic Revelation by the Atlantic Richfield Company (ARCO), the former Anaconda Copper Mining Company. Current Iran?s copper cathode production is about 250,000 mtpa and recently it is targeted to reach to 700.000 t by 2014. The required finance for this target is estimated US $2.25 -b, i.e. US $5000 for each tonne capacity. The copper content of the mineable reserves of the country is estimated about 19 Mt. It is not unlikely this amount increases in close future. Currently, almost 30 projects consist of mine, concentrator, smelter, refinery, acid plant, leaching, bio-leaching are underway. These projects are a golden opportunity for the local and foreign companies, but the recent sanctions are very challenging that all studied in this paper.

Jan 1, 2012

By William M. Clark

In 1988, the Chemical Manufacturers Association (CMA) launched Responsible Care®, a program of guiding principles created to address the publics' concern about the manufacture and use of chemicals. The Product Stewardship Management Practice code is a key component of the program. Along with the other five comple­mentary codes - Community Awareness and Emergency Response (CAER), Pollution Prevention, Employee Health and Safety, Process Safety, and Distribution - it has been initiated to protect the health and safety of member companies employees, neighbors, customers, the public and the environment. Possibly no other Management Code requires greater collec­tive effort or comprehensive commitment to implement than Product Stewardship. With its mandated cradle-to-grave control, every employee is required to consider all of the potential cir­cumstances involving product and processes, from raw material supply to customers final use or consumption of product. Degussa Corporation, a long time CMA member, fully endors­es the Responsible Care initiative and is most active in imple­menting the various codes. In fact, the guiding principles of the program are an integral part of the company's business strategy. Degussa recognizes that its long-term success and the health of each of its products, the company and the chemical industry itself, is contingent on the successful implementation of the program. Furthermore, the company believes its role in society and the economy can only be justified and sustained if it improves the overall quality of peoples' lives. Consequently, it is a dictum that Degussa products must provide a net benefit over their entire life cycle - from inception to final disposal - both in terms of their utility and their impact on health, safety and the environment.

Jan 1, 1998

By Anne Kathrine Kalager

"Stretching from Norway’s capital, Oslo, to the city of Ski, a new railway line is under construction with a 20 km long hard rock tunnel. This is a major project with high demands regarding quality, cost and schedule. In addition, restrictions concerning locations close to sensitive urban infrastructure require execution with the highest level of precision and expertise. The new double track railway line forms an important part of the intercity rail development southwards from the capital and includes the longest railway tunnel to date in the Nordic countries. With its novel methods and solutions, this project offers a model for future railway project developments in the region. This paper provides general pertinent details and facts relating to this current railway project and includes a description of the project with information relating to concept and design of the tunnels, geological conditions, particular challenges, selected tunneling techniques and contracting strategies. THE FOLLO LINE PROJECT The Follo Line is a new 22 km long double track railway line under construction between Oslo Central Station and the city of Ski. The project is divided into four subprojects, as shown in figure 1. The main part of the project consists of a 20 km long hard-rock tunnel, which will be the longest railway tunnel in the Nordic countries to date.The Østfold Line is the existing double-track railway line running between Oslo Central Station and Ski serving 12 local stations. The new Follo Line will offer a direct service, without stops, between Oslo Central Station and Ski and reduce the travel time from 22 minutes to 11 minutes. After completion of the Follo Line, these two railway lines will, in combination, more than double the capacity for train transport in the region south-east of Oslo."

Jan 1, 2016