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By Ian McFeat-Smith, Odd G. Askilsrud

Introduction Given the mountainous nature of the local igneous terrain, hard rock tunnelling plays an important role in the development of Hong Kong's infrastructure. In 1990, tenderers for two tunnel projects were encouraged to consider using hard rock TBMs, the territories' first. As a result the 7.5km long, 3.56m diameter Tolo Effluent Tunnel and the 5.3km long, 4.8m diameter Hong Kong Electric Cable Tunnel were excavated by hard rock TBMs. The successful completion of both projects in 1992 should make the TBM method an attractive construction alternative for planned, upcoming projects in Hong Kong. Tunnelling Conditions Tunnelling solutions are frequently adopted in Hong Kong due to the intensity of development, lack of flat landscape and proximity of mountainous terrain to the main centers of population. This is carried out primarily in granites or granitic-type rocks which surround Victoria harbour, and to a lesser extent in the outlying volcanic rocks which include extremely hard tuffs and lavas. Tunnelling will generally take place in granitic rocks, normally about 100-250 MPa in strength, and with an average joint spacing of 0.3m and a quartz content of 30-

Jan 1, 1993

By A. W. Randall

Geological Aspects of Ore Reserve Estimates of Pine Point District Zinc- Lead Deposits, N.W.T. Zinc-lead ores of the Pine Point District, Northwest Territories, Canada are hosted in paleokarst cavities within a Middle Devonian carbonate barrier complex. Of the nearly 100 deposits found, most are irregularly distributed along two main regional stratigraphically controlled trends. The ores, which occur predominantly as open space filling, form deposits most of which average one million tonnes in size with an average grade of 10% combined zinc plus lead. Geological features related to karsting control not only distribution of deposits but also their shape, size and grade. The higher grade ore in these deposits generally occurs in a relatively small core area. Consequently, accuracy of reserve estimation is dependent on drill hole density and understanding of karst geometry. Several case examples will be reviewed to demonstrate the relationship between shape, size and grade of deposit, geological reserves and drill hole density, along with a discussion of geological ore reserve estimation methods.

Jan 1, 1985

By D. Scott Barr

Whole ore roasting using oxygen fluid bed systems was selected for two roasting facilities constructed for Independence Mining Company Inc. in 1989. Independence Mining Company Inc. (formerly Freeport-McMoRan Gold Company) processes refractory gold ores at two facilities located 60 miles north of Elko, Nevada. The Jerritt Canyon project, a joint venture with FMC Gold Inc, processes 2.8 million tons per year of carbonaceous refractory ore by oxygen fluid bed roasting and aqueous chlorination. The fluid bed roasters have been in operation since July, 1989. The Big Springs project has processed 400,000 tons per year of sulfide refractory ore since May 1989 from the Big Springs Joint Venture between Independence and Bull Run Gold Mines, Ltd.. Freeport Research and Engineering of New Orleans, Louisiana was the developer of the innovative technology used in the oxygen fluid bed roasting systems and have been granted a patent on its use. Environmentally, the roasters have exceeded expectations with lower emissions than designed as measured in compliance testing for the State of Nevada.

Jan 1, 1990

By D. H. Stonehouse

There is no such thing as an industrial minerals industry. There are, however, many industries operating in the general field of industrial minerals. And although we use the phrase "industrial minerals industry" out of sheer convenience, the only common denominator among, say, the potash mining and processing industry, the sulphur-sulphuric acid industry and the granite industry is, in fact, that they each are exploiting an industrial mineral resource. May I quote the person whom I consider to be the reigning Mr. Industrial Minerals, Robert L. Bates, who in the 4th edition, 1975, of Industrial Minerals and Rocks states: "An industry is considered to belong to the industrial minerals field if its operations consist of extraction and processing, but not manufacturing. Thus the mining and beneficiation of feldspar is a mineral industry, but the manufacture of ceramic products is not. In the cement and lime industries, processing merges into manufacture, and the line is less distinct. It disappears altogether in a plant that extracts salt as artificial brines, and makes sodium and chlorine chemicals, all under the same roof."

Jan 1, 1981

By T. Wisdom, D. Romo, G. Seale, R. Jansen

Thickening remains relatively misunderstood since it is typically near the end of the process and not directly involved in metal recovery. When operating well, thickeners are ignored and left to run independently, the ‘out of sight, out of mind’ phenomena. However, when operating poorly, there is a lack of basic understanding and remedial actions to solve issues are reactionary rather than proactively addressing shortcomings. This series of papers breaks down in sequential order the stepped phases required to gain an appreciation and thorough understanding of the science behind thickeners, and key thickener components, and basic troubleshooting skills. This second paper starts with identifying the different approaches to thickener test work including static and dynamic settling tests followed by high-rate versus paste thickening. Complimentary to test work, the mechanisms surrounding coagulation and flocculation are presented and explained. The basic mechanisms for coagulation and flocculation are discussed to support the different test work approaches and provide the reader with the basic background.

Mar 2, 2022

By G. H. Schnakenberg

In 1986, the US Bureau of Mines (USBM) embarked on a major research effort to develop technology that could substantially reduce worker exposure to face hazards by simply relocating the equipment operators to an area of relative safety. This reduced-exposure mining system (REMS) research effort enhances the USBM's ongoing health and safety efforts aimed at reducing and controlling dust and noise and reducing accidents through training and better mining practices. This paper reports on the progress made on the developing research and demonstrates the technologies required for the computer-assisted teleremote operation of continuous mining machines, haulage systems and roof bolting machines.

Jan 1, 1997

By K. K. Bhattacharyya

In the Gulf Coast area lignite deposits occur in Texas, Louisiana, Arkansas, Mississippi and Alabama. Lignite has been mined in Texas since the early 1800's reaching a production of over 900,000 metric tons (1 million short tons) in 1910. With the availability of inexpensive oil and gas, production fall to as low as 16,000 metric tons (18,000 short tons) by 1950 (Henry, 1976). With the advent of the oil and gas shortage in early 1970, lignite production began to increase again. The purpose of this paper is to discuss the geotechnical considerations of mining lignite in the Gulf Coast area, particularly Texas and Louisiana. Lignite deposition occurs in unconsolidated sand, silt and clay environments. Extensive sand units saturated with water may be present within the potential mining depths. This paper describes the geotechnical considerations for designing a surface mine in this geographical area. These factors include geology, hydrology, mining method, and equipment utilization.

Jan 1, 1982

By David A. Greenhut

The Kubota surface melting system has been under development since 1975. It has found commercial application on the melting of municipal sludge, and ash from solid waste. The melted product has physical properties allowing its use as a substitute for aggregate in cement and asphaltic construction. This paper describes the surface melting system, its current use and anticipated future use.

Jan 1, 1991

By W. Wan

Diesel particulate matter (DPM) emitted from diesel engines is currently considered to be a health problem in underground mines. As a result, attempts have been made to control DPM both by reducing emission rates and by managing the DPM that gets into the mine atmosphere. This paper presents a method for modeling the generation, transfer and distribution of DPM in the mining sections through the use of a convection-based computer model so that controls for emitted DPM can be evaluated. A variety of ventilation strategies and diesel deployment schemes for room-and-pillar development sections were simulated to compare their effects on average DPM concentrations at several fixed and mobile personnel locations in the section. Input data for the model was gathered from actual diesel development sections and derived from experimental study results provided by other researchers. Studied using the model were ventilation schemes using vent tubing and brattice, exhaust location strategies on the vehicles, and the direction of ventilation at the feeder-breaker location. A summary of results from this study will be presented.

Jan 1, 1994

By R. L. Garrett

The quality of mineral additives used 1n a drilling fluid (mud) can dramatically affect the fluid's properties and the overall cost of drilling an oil or gas well. The principally used minerals are bentonite, barite, barite/hematite blends and hematite alone. The high specific gravity minerals, barite and hematite, are used to increase drilling fluid density. Bentonite clay is used to increase drilling fluid viscosity, gel strength and to provide a low permeability filter cake. A multi-million dollar investment in a well and the safety of the personnel on the drilling rig can depend on how effectively these mud additives perform with other constituents in the mud. This paper points out effects caused by small amounts of certain carbonate and sulfide mineral impurities in barite or hematite and how polymeric extender additives in bentonites contribute to unpredictable behavior of a mud. Effects like these are the reason why oil companies who use these materials sometimes set their own quality standards beyond those already specified in API Spec. 13A. Also discussed in this paper are the current standardization activities in API Committee 13 on these minerals.

Jan 1, 1986

By W. T. Reid

Analysis of the energy resources available in the United States confirms that coal will be needed to satisfy the future energy needs. The trends in the market place, particularly economic and political, suggest that the bulk of the coal will be consumed for generation of electricity. The utilization of coal to produce electricity will require technical solutions to the variable characteristics of coal and ash, development of methods to improve coal quality, and public acceptance of the cost of compliance with environmental standards.

Jan 1, 1983

By John P. Weir

The planning of an underground mine for successful extraction of a bedded deposit in sedimentary rocks requires the integrated evaluation of many interdependent problems. The development and coordination of feasible solutions are the responsibility of the mining engineer. One of these problems will be discussed herein; this is the design and .layout of mine workings to secure effective control of the strata above and below the deposit. The objective is the simplest possible repetitive system permitting safe maximum recovery at optimum cost. Mining conditions to be encountered must be predictable. The best mining equipment is ineffective unless strata are controlled. Conversely, a mining layout is only of academic interest, if equipment can not be adapted to work it with adequate provision for ventilation, compliance with mining laws, proper ingress and egress and other practical requirements. Strata control, then, is but one of the mining engineer's problems, and the solutions must be worked out concurrently with solutions to other problems. Dr. Karl F. Fetters in his introductory remarks before the Fourth International Conference on Strata Control and Rock Mechanics at Columbia University said that mining engineering ?has come from the stage of empiricism backed by intuitive reasoning, to where it is based on fundamental scientific and engineering principles?. The standard curriculum in mining engineering now reflects such a change. In common with other branches of engineering education, less and less emphasis is placed on practical skills and more and more on broad scientific education. Science, research and the quest for basic truth are stressed, while descriptive courses and the teaching of specific skills are limited.

Jan 1, 1966

By William E. Mead

The process of selecting a building site for a major structure is a complex procedure involving the consideration of a multitude of factors. The approximate geographic location for a structure is usually fixed by its intended function, though often there may be several site alternatives. Socio-economic, logistic, marketing and political factors are the primary site determinants. Also critical in site planning, however, are the environmental factors, both natural and man-made. These factors will influence the precise siting location within the limits allowed by the primary determinants and will dictate some of the basic design criteria. This paper discusses environmental factors, principally those which are natural conditions, that must be analyzed for five different groups of structures. The importance of thorough site environmental analysis based upon the principles of applied earth science is described. Significant elements to be considered in an appraisal of the geology, hydrology, seismology and meteorology are outlined.

Jan 1, 1968

By R. E. J. Putman

Rising demand, artificial market conditions, increased overseas competition, and a fluctuating international situation have brought ever increasing pressures to bear on the nonferrous metals industries, and particularly in the United States, Although capacity is being expanded by the construction of new plants and the development of new ore deposits, increasing attention is being focused on the possibilities of improving the performance of the existing installations and of getting the most out of the new equipment now installed. At first sight the task appears formidable. Based on raw materials which are nonhomogeneous, and possessing characteristics which are hard to quantify, even the processes by which the values in the ores are concentrated and extracted are in many cases not fully understood. The necessary analytical equipment and transducers demanded by these industries have also been slow in development and their earlier absence has hampered the application of modern control technology, This is reflected in plants which have been designed for ease of manual rather than automatic control, and in which the application of control techniques at first sight appears economically prohibitive. However, in any industry progress often comes only in small steps, It may be that by the wise choice of limited objectives and perhaps only partial solutions, substantial improvements in plant performance can be implemented now, and with only a modest investment. If modern control equipment is chosen of the type which can be reprogrammed, advantage can be taken later of more sophisticated solutions as the technology of the industry advances. This task of improving plant performance can and must be commenced even though our knowledge is incomplete. The experience of a related mineral consuming industry, with similar problems in the past, can be encouraging.

Jan 1, 1967

By Justin Carl, Aliuddin Mohammad, Gordon Evans, Steven Bealby, Carlton Ray

"The District of Columbia Water and Sewer Authority (DC Water) is implementing the $2.2-billion DC Clean Rivers Project (DCCR) to control combined sewer overflows (CSO) to the Anacostia and Potomac rivers and Rock Creek, and to provide flood relief to the Bloomingdale and LeDroit Park neighborhoods in the District of Columbia. The long-term control plan complies with the requirements of a Federal Consent Decree entered into by DC Water, the District of Columbia and the United States, as represented by the U.S. Environmental Protection Agency and the Department of Justice. The Northeast Boundary Tunnel, a design-build project, will store combined sewage and deliver it to a system of downstream tunnels and ultimately to the Blue Plains Advanced Wastewater Treatment Plant (Blue Plains), where it will be treated. In addition, the Northeast Boundary Tunnel (NEBT) is a major project associated with the mayor’s task force to alleviate extreme flood events in Bloomingdale and LeDroit Park. The Northeast Boundary Tunnel Utility Relocations (NEBTUR) design-bid-build (DBB) project is an accelerated component of the Anacostia River System, as shown in Fig. 1. During dry weather conditions, the entirety of the sewage in the combined system is conveyed to Blue Plains.During storm events, when sewer pipe capacity is exceeded, the flow, which is a mixture of sewage and stormwater runoff, overflows into receiving waters through outfalls. There are a total of 47 active CSO outfalls along district waterways.The influx of storm runoff into the combined sewer has an additional impact on the communities of Bloomingdale and LeDroit Park. The sewer system is outdated and undersized. In these neighborhoods, when the capacity of the sewer is exceeded, localized flooding occurs and backups into adjacent residences are prevalent. In any given year, there is a 50-percent chance that flooding will occur in these neighborhoods."

Jan 9, 2017

By C. Milne, T. M. Dyhr, T. E. Wilson

As time progresses, new concerns regarding long-term post-mining effects are identified, increasing mine closure costs. Regulators responding to public interest must take a “worst case” view and require post-closure monitoring or remediation processes. Although closure costs depend on the size and type of operation, general cost categories are defined, and median values (per acre, or per unit of production) are identified. Closure cost categories, as well as amounts, have increased with time. Except for increased efficiency in earth-moving and water management (surface or subsurface), there are no apparent offsets to a steady rise in closure costs. When the historical trend of closure costs is considered, it is probable that additional cost categories will come into being. For mine operators, the challenge will be to anticipate them and devise cost-effective remedies.

Jan 1, 2003

By P. Zhu

The leaching behavior of copper powders recovered from waste printed circuit boards (WPCBs) was investigated using electrogenerated chlorine and aeration in a sulfuric acid solution with added NaCl and CuSO4. Various parameters were studied to understand the mechanism of the copper leaching. When the current density increased from 0 to 0.1 A/cm2, the temperature from 30 to 60° C, agitation speed from 100 to 400 rpm, and the size ranged from below 75 to 150 µm, the leaching ratios of copper powders increased. The leaching kinetics were analyzed using a shrinking core model: 1-(1-X)1/3 = kt, and the leaching process was chemically controlled with an activation energy of 14.7 kJ/mol due to Cl- ion catalysis. The ratios of [Cu+]/[Cu2+] at various temperatures (30, 40, 50, 60 and 70° C) showed a periodic variation with the increasing of the leaching time. The redox potentials of the leaching solution and copper leaching ratios in different conditions were measured. The result indicates that dissolved oxygen achieved the dissolution of coppers and electrogenerated chlorine can promote the dissolution of copper powders and improve the reaction rate of kinetics in the presence of oxygen.

By T. J. Fenner

Research conducted in South African mines has demonstrated the benefit of ground penetrating radar for the detection of geologic features and hazards. This is crucial for safety and production considerations in underground mines that are as much as 4 kilometers deep. This paper describes a new ground penetrating radar system designed specifically for high quality data acquisition, in the harsh conditions of deep underground environments, for use by operators with minimal geophysical experience. Design criteria included automated functions, intrinsic safety, light weight and minimal power requirements. Data is processed on the ground surface by geoscientists using a PC.

Jan 1, 1994

By Donald D. Haas

This presentation will discuss a mine owner's evaluation to utilize a contract miner in the development and production of gold properties. I will address both the quantitative and subjective aspects of the evaluation process. The quantitative aspects include cost evaluation, capital preservation, acquisition and disposal of new and used equipment, administrative costs, recruiting and training, and organizing a staff and craft labor force. The subjective areas of this discussion include corporate philosophy, administrative concerns, contractor competence, loss of owner control, operating flexibility, financing assistance, recruiting and training program utilization and risk reduction. The evaluation of alternatives provides a system for comparing, on a cost basis, an owner/operator system vs. a system using a contract miner. The supplement provides a concept on how a contract miner may be the cost effective system to be utilized.

Jan 1, 1989

By T. F. Torries

Identifying high value areas of unmined coal when large quantities of coal are available relative to annual markets is difficult because of the uncertainty of when the coal is to be mined. A GIS based methodology developed to value reserve coal in a producing coal region for the purpose of ad valorem taxation also identifies high value areas for mining investment. The methodology is unique in that it accounts for most mining, environmental, and market factors to determine when specific properties are to be mined. The methodology and data base are useful for directing regional exploration and acquisition activities toward most favorable areas.

Jan 1, 1999