Search Documents

By Elisa Comis, David Chastka, Miriam Piemontese, Maria Chastka

The Lower Olentangy Tunnel (LOT) Project involves the construction of a 17,000 ft (5,200 m) long, 12 ft (3.65 m) internal diameter Combined Sewer Overflow (CSO) tunnel. The tunnel is excavated by using an Earth Pressure Balance (EPB) machine designed to cope with soft ground, weak rocks and water pressure. The project is located in the city of Columbus, Ohio and the main geotechnical hazards are related to the heterogenous soils and the low overburden in an urban environment. This paper focuses on the performance of the EPB first drive and the comparison between the design assumptions and the actual TBM performance during construction.

Jun 23, 2024

By Erwin K. Roesner

The difficulties encountered while sinking deep shafts for Potash Mines in southern Saskatchewan have been the subject of several papers in the past. Geological and hydrological conditions of the strata overlying the potash deposits require special techniques for ground and water control during shaft sinking. The easily soluble potash ore requires the lining of these shafts to be virtually watertight to assure long term and safe operation. This paper describes the construction of the most recently completed potash shaft for the Potash Corporation of Saskatchewan. The shaft was designed and constructed by Thyssen Mining Construction of Canada Ltd. and it is located near Lanigan, approximately 110 km east of Saskatoon.

Jan 1, 1980

By H. Schultheis

The European Commission has launched in April 2002 the Thematic Network NESMI with-in the FP5 under Growth. NESMI stands for ?Network on European Sustainable Mining and Processing Industries? and will run until 2005. Within NESMI there are different ways to set up indicators and evaluate them throughout the NESMI Members. First analyses concerning the Demand and Competence within NESMI are developed. New focus points for analyses can be implemented into NESMI.

Jan 1, 2003

By K. Terhaar

The objective was to determine operating protocols for a lead and silver column flotation cleaner, being considered for installation at Sunshine Mining & Refining Co.'s Kellogg mill in Northern Idaho. In this column, tetrahedrite and galena were floated, and pyrite and other gangue minerals, including siderite and silica, were depressed. The procedure was to develop a dynamic simulation using a linear transfer function approach. The transfer function related cause and effect variables such as the influence of collector and depressant dosages on recovery and grades. Bench-scale flotation tests followed by pilot column testing provided the data used to develop a linear transfer function. The transfer function was derived using a spreadsheet. This model was applied to simulate how the flotation column could be made to respond to disturbances in feed grade. The results were that xanthate, zinc sulfate, and sodium cyanide were found to be suitable controls for grade and recovery. Simulations showed the best sequence of manipulations of these reagents, and these sequences were useful for future operator training. The conclusion was that linear transfer functions were able to simulate lead and silver recovery, develop scenarios for operator training, and provide a foundation for future on-line control.

Jan 1, 1999

By Vladimir Adamek

Due to the variability of subsidence characteristics across the U.S. coalfields, it was concluded that it would be practically impossible to develop a universal predictive model for mining-induced subsidence based on theoretical assumptions. Therefore, an effort was made to find a procedure to develop an empirical subsidence predictive model based on a sufficient Mount of field data from one mining area (in this case the Northern Appalachian Coal Region). It was also thought that this procedure, if successful, could be used as the template for developing predictive capabilities for other coalfields with different subsidence characteristics given a reasonable amount of field data. It has been found, in the Northern Appalachian Coal Region, that the variability of subsidence characteristics can be expressed by a polynomial equation developed through regression analysis of the variable subsidence coefficient and derived directly from the field data. In this study, field data were obtained from 11 Bureau longwall panel studies (16 half profiles) for static subsidence and 14 panels for dynamic subsidence. The effects of lithology, expressed in the form of a variable subsidence coefficient, have been separated for each test site by introducing a correlation between hythetically homogeneous overburden and existing ithological conditions. For each longwall panel, the characteristic of the variable subsidence coefficient was defined along individual static profiles. The definition of mean values with acceptable deviations is the substance of the predictive method. The same procedure was used to develop a predictive model for dynamic subsidence, since it war discovered that the rate of longwall face advance is not a necessary functional parameter. This paper presents the theory, development, and application of the static and dynamic subsidence prediction models.

Jan 1, 1986

By Shamim A. Dar, Mohd Shuaib, K. F. Khan, Samsuddin Khan

Petromineralogical studies of late Paleocene–middle Eocene phosphate nodules in the Subathu Basin of Solan District, Himachal Pradesh

By A. V. Glembotsky, N. A. Greshnova, V. P. Seregin, V. A. Glinkin

Based on a new alternative depressant of zinc sulphide - dimethyldithiocarbamate- modern technology has been developed for the treatment of complex polymetallic ores. In addition to its general function (depression of sphalerite and iron sulphides to some extent), this double-acting reagent is a promoter for galena and silver minerals. Laboratory and plant tests, as well as industrial experience have all shown consistently higher silver recovery to the lead concentrate as compared with sodium cyanide, resulting in less pollution and a safer environment

Jan 1, 1995

By Fangyu Liu

In the grand tapestry of scientific inquiry, there are individuals whose contributions resonate far beyond the confines of laboratories and lecture halls. It is with profound admiration and respect that we present this special collection of Mining, Metallurgy & Exploration, dedicated to celebrating the remarkable career of Dr. Patrick Taylor. Dr. Taylor, recently retired from the Colorado School of Mines as the Emeritus Ansell Distinguished Professor of Chemical Engineering, possesses over 45 years of expertise in mineral processing and extractive metallurgy. His remarkable journey has seen him traversing the globe, from Canada to Egypt, contributing to pyrometallurgy, hydrometallurgy, and mineral processing. Dr. Taylor’s portfolio encompasses lab work, pilot-plant projects, research, and process development across various metals, with an impressive array of authored papers, presentations, and nine patents to his name. A soughtafter consultant for over 20 companies and an esteemed expert witness, Dr. Taylor also led the Kroll Institute for Extractive Metallurgy at Colorado School of Mines. Under his guidance, more than 100 graduate students and post-docs have undertaken transformative research, while Dr. Taylor’s 45-year tenure as a university lecturer and the creation of 10 industryfocused short courses underscore his dedication to knowledge dissemination. His contributions extend to crafting professional engineering exam questions for a quarter-century and active participation in esteemed organizations like SME, TMS, ASM, and MMSA.

Sep 16, 2023

By B. Rao Pothini, Julio H. Thaler, W. L. Finlay

The White Pine room-and-pillar mine started in 1955 from a suboutcrop, down gentle dips, and with a competent sandstone roof. As mining depths increased, extraction decreased 1% every 35 feet. Moreover, roofs became shaly and less competent, and regions of high fault and joint densities, sometimes with and some- times without high lateral stresses, increased the tendencies towards roof falls. Instinctive reactions towards narrower openings did not alleviate the problem. Careful consideration of rock mechanics principles culminated in the development of two variants to the conventional room-and-pillar mining system based on the concept of stress relief through load deflection. The two systems-EquiAdvance Cave, and PressureArch Panel Mining-are complementary. The objective of the former system is to provide relief from lateral stresses through advance caving and in the process also to achieve higher extraction at depth. Where surface subsidence cannot be allowed, the alternative PressureArch Panel concept is utilized to provide stress relief and moderately high extraction ratio. Both systems have been under trial for over three years and, together, produced over three million tons of copper ore. These two systems, and their production test results to date, are described.

Jan 1, 1977

By Christopher Haycocks, Randolph Reed, Erik C. Westman

The industrial Source Complex (ISC3) model is the accepted standard used to predict emissions of particulate matter less tan 10µm in diameter (PM10) from industrial operations. This model, however, over-predicts PM10 emissions from surface mining operations, making permits harder to obtain. The over-prediction is likely due to the fact that the model applies emissions from mobile (dynamic) sources to stationary (static) areas. Utilizing a Gaussian dispersion equation, a Dynamic Component Program was created to correct the over-prediction of the model and results in a much more realistic modeling of actual conditions from mobile sources.

Jan 1, 2002

By A. A. Campoli

The U. S Bureau of Mines is conducting research to develop improved guidelines for selecting the type and pattern of roof support in different geologic environments (Mucho, et al., 1995). As a part of this wider research effort, a multifaceted ground control investigation was conducted at the Diamond TB Mine of RoxCoal, Inc. The study included statistical analysis of mine-wide roof bolt performance, instrumented bolt test areas, stress damage mapping, and pillar design analysis. The mine employs state-of-the-art continuous miner technology, including mobile roof supports and continuous haulage, to retreat mine the Lower Kittanning Coalbed. A herringbone section design makes the stability of the center belt entry critical to efficient retreat mining. Roof cutters formed during section development sometimes set up unstable immediate roof conditions in advance of the belt entry mobile roof supports during retreat mining.

Jan 1, 1996

By William Petruk

Lithium bearing lepidolites from three deposits in the province of Goias in Brazil were investigated to determine whether there is a correlation between the lithium content of the mineral and the colour of lepidolite and associated tourmaline. Such a correlation can be a useful guide to field geologists for outlining high grade ore zones. It was found that mauve-pink lepidolite associated with pink tourmaline, and brownish lepidolite associated with black tourmaline have high lithium contents, but the colour of lepidolite is not due to lithium. The pink colour of lepidolite and tourmaline is likely to Mn3+, and the brownish tint of lepidolite and black colour of tourmaline to Fe3+. Lepido lites appear to be lithium-rich when the lepidolite and associated tourmaline contain relatively high amounts of Mn3+ and/or-Fe3+.

Jan 1, 1985

By Christopher J. Pritchard

Federal mine safety regulations prohibit the recirculation of face air In a gassy Class III metal-non metal mine. Tg Soda Ash, Inc, operates a 2.0M ton/yr (2.2 million st/yr) underground gassy Class III trona mine In southwest Wyoming, currently liberating approximately 5,700 m3/day (200,000 ft3/day) of methane. Because of the low methane emissions and the incombustibllity of trona, it was decided that Tg would be an excellent environment to test recirculation at a U. S. gassy mine, for possible future use by Industry. A research program was begun with the cooperation of MSHA, the U.S. Bureau of Mines, the University of Utah, and Tg. Initial testing centered around re-using shop air under¬ground. Next, conduct a continuous miner section recirculation test to see how the face contamination was affected by 305m (1,000 ft) and 610m (2,000 ft) recirculation distances. A district test followed to examine the effects of the critical parameter - respirable dust. Finally, a long-term program to study respirable trona dust transportation and deposition in mine airways to plan for district fan siting and effects on face air dust levels.

Jan 1, 1995

By A. M. Elmherig, M. R. Sunu, R. N. Singh

The presence and orientations of fractures and discontinuities in rock masses exposed in a surface mining excavation are likely to have a great influence on both slope stability and blasting efficiencies. The classification of rock materials requires detailed investigations which are of interest to the design engineer. In designing a safe mining excavation, an engineer must take a number of decisions regarding face support and orientation based on the evalu¬ation of local strength and structural conditions encountered. The description of rock masses requires information additional to the properties of the rock material, discontinuities and other characteristics of engineering importance. Such information involves the acquisition of the following data: The description of the rock mass with reference to major geological structures. The orientation, nature, spacing and persistence of discontinuities. Degree of weathering. A critical review of rock mass classification systems and their application to surface mine excavation design and stability analysis is presented. The field investigation techniques for collecting rock mass data are described together with the techniques of analysis and presentation of data. Laboratory tests are carried out to determine intact rock strengths and deformation parameters of rock. The paper presents two case studies from the British hard rock surface mining industry to illustrate the application of the rock mass classification systems to stability analysis and excavation design.

Jan 1, 1986

By W. Reed

During the 20th century, the increased emphasis on worker health and safety and the advent of new mining equipment and methods led to many changes in mine face ventilation practices. Efforts by government and private industry to improve and modify ventilation practices resulted in better health and safety conditions for workers. This paper examines factors that had a significant influence on mine face ventilation design during the past century. Several “milestone” events are discussed along with the impact they had on worker health and safety. Significant ventilation research efforts by government and private industry are presented. This brief ventilation history highlights innovative ventilation designs and a consistent commitment to mining health and safety.

Jan 1, 2007

By G. D. Mainwaring, Weng L. W, Lam Y. K.

The first power transmission cable tunnel in Singapore was the 2.6km long undersea tunnel between Pulau Seraya and mainland Singapore, constructed in the1980s. Ten years later, similar concepts were used for the Tuas Cable Tunnel. The tunnel, which includes a 2.2km long immersed tube section, was designed to accommodate 10power circuits of 400kV and 230kV capacity. It is fully equipped with sophisticated control and communication equipment, fire suppressant and life safety systems plus a maintenance vehicle which runs on tracks through the length of the tunnel. The paper discusses the planning, design, and construction of the Tuas tunnel, and the development of these concepts for future tunnels.

Jan 1, 2001

By Erie F. Wolstenholme

The purpose of this paper is to describe work undertaken, within the System Dynamics Research Group at Bradford Management Centre, into the development and application of a System Dynamics model of an international mineral industry; aimed at providing a basis for analysis of the interrelationship of supply, consumption and price over time, under different production and stocking policies. A review is presented of some of the major characteristics and problems associated with such industries. This is followed by an outline description of the model and the way it has been applied to examine various supply responses, in the light of changing consumption patterns. Demonstration results deal with model validation and with analysis of international buffer stocks and conflicting supply policies on the historic situation in the copper industry.

Jan 1, 1979

By Hiroshi Himura, Shoichi Tsushima, Hiromi Goshima

This paper reports the construction of an environmentally-friendly tunnel in sedimentary soft rock near a residential area. The main tunnel, which will be used as the Onmawashi-Koen (Park) Regulating Reservoir, is a large-scale tunnel with a cross sectional area of 254.0 m2 and a lengthof 577.3 m, excavated using such support as shotcrete, rockbolts and steel H-sections. Since the large main tunnel is excavated in sedimentary soft rock, it is necessary to keep the stability of the tunnel face and the crown and to prevent surface settlement. A top heading with a length of 50 m is therefore driven as a pilot tunnel to observe the ground behavior during excavation, and to obtain information on the geological conditions based on which type of support structure is determined with consideration given to the results of field measurements and numerical analyses.

Jan 1, 2001

By S. Harteis, D. Dolinar

Many mining operations rely on bulkheads to provide a barrier between impounded water or slurry and active mine workings. However, bulkhead failures could cause and have caused catastrophic flooding that puts the underground workforce at risk. The National Institute for Occupational Safety and Health1 (NIOSH) in collaboration with the Mine Safety and Health Administration (MSHA) is conducting research to evaluate the adequacy of existing design practices for water and slurry bulkheads. A key component of this research effort is documentation of the performance history and design parameters for bulkheads installed in underground coal mines during the last 20+ years. This research is part of a larger effort to develop general design guidelines and procedures for constructing and maintaining bulkheads that will help to ensure their long-term structural integrity, while significantly reducing the inundation risk for miners. This paper presents the results of NIOSH’s research to identify state-of-the-art bulkhead designs, including design criteria, leakage monitoring systems, and emergency warning systems. Underground observations and evaluations of existing bulkheads suggest that the most important design factors influencing their performance are the interface of the bulkhead with the surrounding strata and the potential magnitude of the hydraulic pressure to which they may be subjected. When a bulkhead has failed, leakage has generally been through the surrounding strata or along the bulkhead/strata interface, with the failure potential along the interface increasing with hydraulic head. It was also determined that development of a monitoring program to ensure the long term structural integrity of bulkheads is an important safety consideration. Current monitoring procedures range from weekly visual inspections to constant monitoring via pressure transducers and fluid level indicators. Where possible, these devices are used in conjunction with a computer based mine monitoring system to alert mine personnel when an emergency condition exists at the bulkhead installation.

Jan 1, 2006

By Abdullah Arik

In deposits with highly skewed grade distributions, such as precious metals deposits, proper handling of the outlier high grade data is very crucial to the ore reserve estimation. Although some recent geostatistical techniques are available to handle the estimation problems with these outlier data, ordinary kriging or conventional methods are still widely used to estimate the ore reserves for such deposits. One reason for this is the fact that the alternative methods offered are either too complex or too exhaustive for the mine engineers and geologist who often do not have the expertise or the time to apply these methods. This paper presents a new 2-step kriging algorithm "Outlier Restricted Kriging" (ORK) which can be a simple and a practical tool to use where the ordinary kriging will fail to handle the outlier high grade data properly in block grade estimation. The paper details the methodology and discusses the results of its application to a gold deposit.

Jan 1, 1992