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By Hooman Askari-Nasab, AHLAM MAREMI, EUGENE BEN-AWUAH

In oil sands mining, tailings are voluminous unwanted byproducts generated from extracting the desired mineral from the mined ore. Dyke construction and backfilling activities require well-managed techniques to facilitate progressive reclamation at the earliest opportunity. This directly affects the sustainability and profitability of the mining operation. This research introduces a goal programming framework that simultaneously optimizes the (1) production schedule with limited duration stockpiling and directional mining, (2) dyke construction schedule, (3) size, shape and location of tailing cells and (4) mining and processing production targets. The results show that in creating in-pit tailing-cell designs, decreasing the mining-cell volume and increasing the number of mining cells improves the net present value (NPV) of the operation due to increased operational flexibility.

By James R. Yancik

Economical and environmental pressures necessitates the recovery of the minus 0.6 mm x 0 coal generated by todays mining machines. This size fraction, dependent on the type of production unit, maintenance of the production unit, and the Hardgrove Grindability Index, can be a substantial portion of the Preparation Plant feed. Historically, dewatering of the collected 0.6 mm x 0 product has often been rather expensive and marginal with respect to surface moisture reduction. The Freeman United Crown II Preparation Plant more than adequately demonstrates that the continuous scroll type centrifuge can dewater 0.6 mm x 0 coal to acceptable surface moisture levels.

Jan 1, 1981

By G. Gaidajis

In this paper, a semi-qualitative methodology is presented and then applied to an aluminium extrusion industrial facility in order to perform an initial environmental assessment. The results of the assessment enable an improved understanding of the environmental performance of the facility and more importantly identify the areas of significant environmental concern. Following, the application of case-specific sustainability indicators related with the areas of significant environmental concern, leads to a more comprehensive sustainability assessment. The applied two-step approach offers a quick and reliable environmental assessment and help focusing on the most environmentally problematic areas. Moreover, the follow-up of the specific indicators seems to be appropriate for the improvement of the environmental performance of the examined industrial facility.

Jan 1, 2008

By Alan Dahlstrand

The Jamestown Mine is a 6.3-kt/d (7000-stpd) open-pit gold mining operation located in the central portion of California's historic Mother Lode district. Most early production from the Jamestown area occurred in underground operations from 1906 through 1916. Pit production began at Jamestown in early 1987 and continued until July 1994. Although additional mineral resources existed, they were deemed to be uneconomic. About 23.3 t (750,000 oz) of gold were produced from pit operations, compared to 31 t (100,000 oz) from early underground mining. Recent operations at Jamestown included two open pits, a flotation mill and a flotation tailings facility. Flotation concentrates were produced in Jamestown and shipped to Yerington, NV for cyanide leaching in a carbon-in-pulp (CIP) circuit.

Jan 1, 1995

By Ken A. Pfaff, Ray Daigh

This paper will discuss state-of-the-art applications of GPS automation in mobile conveying systems. Robotic mobile conveying systems increase profitability, optimize stacking and reclaiming operations, and control complex interfaces more accurately than other systems. We will also discuss the application process in machine-to-machine coordination, selection of the appropriate GPS system, and Ethernet considerations. As the leading supplier of GPS-controlled mobile conveying systems, we'll draw on our experience at Morenci, Radomiro Tomic, Zaldivar, El Abra (Figure 1), and El Tesoro mines in the US and South America to demonstrate system reliability and the lessons we've learned through analysis of these projects.

Jan 1, 2002

By Thomas A. Boyce

Introduction Although innovative coal extraction technology can be approached from many angles, this paper focuses on three: innovation in response to rising costs, to changing mining conditions, and to regulatory issues. Before exploring these three subjects, however, a basic question needs to be raised. Why Innovation? Coal is widely heralded, and quite correctly so, as the United States' "ace in the hole." It has been said that the U.S. is to coal what the Arabs are to oil. The implication is that we have nearly inexhaustible reserves - that coal is cheap, plentiful, and easy to extract. Indeed, because our current productive capacity is estimated to be 15-20% greater than demand, we have been given a false sense of security about the ease of future coal extraction. Therefore, innovative measures are being concentrated on developing technologies for the demand side of coal, including power generation, synthetic fuels, and industrial applications. What is often forgotten is that the unit cost of producing energy from these new technologies depends critically on the cost of the coal feedstock -in some cases the coal consumed accounts for more than one-third the total cost. Thus, while the developers of the end-use technologies struggle to improve the overall thermal efficiency of their process by one or two per¬centage points to make the energy produced competitive in the marketplace, they often are unaware of the risk of a 3 to 6% increase in coal costs wiping out the expensive, hard-earned results of their research. Energy planners are just beginning to realize that coal is not a uniform commodity available at low cost in infinite quantities. Coal is a heterogeneous material whose cost and quality vary widely with local conditions. To produce the massive amounts of projected coal-based energy at reasonable costs, we urgently need devel¬opments in extraction technology, as well as in end-use technology. Thus, coal extraction, coal conversion and utilization, and end -use energy consumption must be viewed as highly interdependent parts of an energy supply network (Fig. 1). And current emphasis on conversion and utilization must be balanced by more emphasis on upstream technologies, including coal extraction. Even more important, the impacts of innovation (or the lack thereof) in any one technology area in the energy supply network need to be discussed and understood by those working in each of the other areas. Why innovation in coal ex¬traction technology? Figuratively, we are all in the "coal boat" together - geologists, miners, transporters, processors, power producers, distributors, and consumers. Innovation is required from each of these sectors to overcome the obstacles that prevent greater use of our most abundant national energy resource. All other links in the coal energy supply network depend on large volumes of coal produced at reasonable costs. Declines in productivity, therefore, must be reversed; the more difficult mining conditions that will be encountered call for new methods and equipment, and regulatory issues must be resolved if the coal ex¬traction link is to be a strength rather than a weakness in the planned U.S. transition to an economy based more on coal and less on imported petroleum. Innovation Tailored to Regional Conditions Once the importance and urgency of innovative coal extraction technology has been grasped, the next step - implementing a research program - becomes quite

Jan 1, 1980

By G. Heiken

On the Earth's Moon, obvious hazards to humans and machines are created by extreme temperature fluctuations, low gravity, and the virtual absence of any atmosphere. The most important other environmental factor is ionizing radiation. Less obvious environmental hazards that must be considered before establishing a manned presence on the lunar surface are the hazards from micrometeoroid bombardment, the nuisance of electro-statically-charged lunar dust, and an alien visual environment without familiar clues. Before man can establish lunar bases and lunar mining operations, and continue the exploration of that planet, we must develop a means of mitigating these hazards.

Jan 1, 1991

By John Zeni

In Australia during the 1990s, Zeni Drilling took on several demanding shaft boring contracts. This paper describes the safety, operational, technical and environmental advantages derived through the implementation of mechanized boring methods for two of these projects. The paper first describes a 3-meter (10 ft) diameter access shaft blind bored from an underground location to 440 meters (1,444 ft) deep for a gold mine in Tasmania. The construction of a 5.8-meter (19 ft) diameter, 515-meter (1,690 ft)deep ventilation shaft for a longwall coal mine in New South Wales is also described.

Jan 1, 2001

By R. J. Wesely

It is obvious from recent events in The Peoples Republic of China that a major effort is underway to increase trade with the Western World. The production of Gold contributes to China's ability to participate in international trade and consequently they place a high priority on increasing gold production. Many of the operating gold mines in China contain refractory ores which to date have not been efficiently treated. Figure 1 illustrates the description and location of some of the major gold mines in China. Recognizing that the technology necessary for the economic treatment of this ore has been developed in the United States and other Western Countries, China has begun to seek assistance in evaluating several potential projects. This paper will examine the recent history and current trends in developing a refractory gold treatment project in China.

Jan 1, 1993

By M. Ericsson

The extractive industries consist of five major sectors: - Mining equipment and services - Dimensional stone - Industrial minerals - Aggregates - Metal mining These industries produce some finished goods but mostly semi-finished products as they feed into other industrial sectors: Basic metals, fabricated metals, construction, chemicals, dyes and pigments, inorganic chemicals, fertilizers, rubber and plastics and non-metallic mineral products. These are the major down-stream industries in this study. Taken together with the extractive industries they form the mineral resource based cluster. The mineral resource based cluster is a substantial part of the Finnish economy: It employs 211 000 persons, 39% of the number of employees in industry. The cluster?s exports account for 20% of industry exports. Value added is 34% of total value added in industry. Investments reach 35% of total industry investments.

Jan 1, 2003

By H. Suharyono, R. Hogg, P. Bunnaul

The flocculation of fine-particle suspensions by polymers is a nonequilibrium process whose performance is strongly influenced by physical as well as chemical variables. A standardized test procedure has been developed that provides quantitatively reproducible measurements of process performance in terms of the floc settling rate, supernatant turbidity and sediment compressibility. The procedure provides information on the development of flocs in response to polymer addition and on their degradation behavior during subsequent handling. Extensive experimental observations using a variety of solids and flocculant types have been used to develop criteria for reagent selection and process design. It is shown that the appropriate choice of reagent(s) is determined primarily by chemical factors (solid type, solution chemistry, etc.). However, actual performance depends more on physical variables, such as agitation intensity and the rate of flocculant addition. Some general guidelines for flocculant selection and process design in industrial applications are suggested.

Jan 1, 1994

By A. C. T. Bigg, Y. Kocak, N. K. Bodur

The Gumuskoy silver mine, owned by the Etibank, in the province of Kutahya, Turkey, has been operating since 1987 with primary, secondary and tertiary crushers, and two parallel single stage ball mill circuits. Continuing problems with crushing and feeding of the ore to the ball mills, because of the moisture retaining and sticky nature of the ore, prompted an investigation into the possibility of converting the grinding circuit to an autogenous or semiautogenous grinding circuit. This would remove the bottleneck associated with the secondary and tertiary crushing. At the same time the target feedrate is to be raised from 140 t/h to 175 t/h. This paper demonstrates the response of five ore types, and blends of ore types in an onsite pilot plant test program, and also suggests how the variations can be handled in a SAG mill/ball mill circuit incorporating just one of the present ball mills.

Jan 1, 2000

By Drupad B. Desai, Alexander Rosenbaum

In recent years, there has been an increasing use of two-pass tunnel lining system consisting of segmental unbolted expandable precast concrete initial lining and cast-in¬place concrete final lining in the United States. Used so far in soft ground tunneling performed under free air, it often includes a waterproofing or gasproofing membrane placed between the initial and final linings. This paper describes the utilization of this two-pass system for an extension of the Baltimore Metro, constructed in part under compressed air. It offers a description of the extension project, known as Section C; addresses the tunnel lining selection process and the design of the lining elements; examines the effect of the adopted lining system and tunneling technique on the design of the project's major structural components; and describes design modification instructions in order to accommodate constantly changing field conditions.

Jan 1, 1993

By Jorma Miettunen, Reijo Kalapudas, Pertti Koivistoinen

A new method for measuring the mill filling was developed by Outokumpu’s Pyhäsalmi concentrator during 1989-90. The method utilizes the power draw oscillation which is caused by the mill lifters. Each lifter bar causes a peak in the power draw and thus a continuous oscillation results. In a fixed time scale, the oscillation peaks will shift as the lifter bare hit the mill charge sooner or later depending on the volumetric filling of the mill. Thus the measuring method is based on the phase shift of the power oscillation. So far the measurement is utilized for maximizing throughput of the primary mills at Pyhäsalmi and Enonkoski concentrators and at Harjavalta slag concentrator. The paper describes the new method and the results achieved.

Jan 1, 1992

By Thomas D. Kelly

In 1900, the average U.S. citizen’s average life span was 47 years. He traveled about 1,900 km (1,200miles) in a lifetime and resided in a home with an ice-box for food storage and oil or gas for lighting. He communicated by mail, telegraph and crude telephones with limited availability and range. By 2000, the average citizen’s life span was 77 years. He traveled an average of 19,000 km/a (12,000 miles/year) by automobile alone. He resided in a home with many electrical appliances, including refrigerators and electric lights. And he communicated almost instantaneously with any other part of the globe by several widely available means, including portable phones and e-mail.

Jan 1, 2002

By J. M. Mutmansky, Y. J. Wang

The method usually used to predict the direction of flow in a connecting airway is to conduct a survey of the two existing nodes to be connected by the new pressure airway. It is then assumed that the air will flow from the node with the measured higher pressure to the node with measured lower pressure. This paper examines this direction-of-flow problem using properties of the system characteristic curve for a two-terminal network and specifies some conditions that will ensure that the air will flow in the direction anticipated. It was concluded that the only requirement is that all characteristic curves of the fans in the network should be strictly decreasing. Five numerical examples illustrate some important proper- ties of the direction-of-flow problem.

Jan 1, 2000

By Michael F. Roach, Joseph K. Cavey, Gary E. Taylor

A rigorous horizontal drilling and chemical grouting program was specified beneath the Hollywood Freeway (U.S. Route 101) section of Los Angeles Metrorail Contract C-311.Twin 6.67-m (22-ft.) diameter starter tunnels were to be conventionally mined through amixed alluvial and bedrock face consisting of silty sand, gravel, and weathered sandstone and siltstone of the Topanga Group. The contact between the alluvium and bedrock dipped toward the Crossover Excavation where the horizontal drilling and grouting operations were performed. The intent of this grouting program was to stabilize the mixed face to minimize ground loss and surface settlement, and to reduce groundwater inflow into the tunnel headings. Given the highly variable mixed face conditions, horizontal drilling up to 86 m (284 ft.) resulted in upward trending trajectories which likely followed the bedrock contact. Chemical grouting was performed in a primary, secondary and tertiary, three dimensional sequence. Evaluation of the primary and secondary grouting parameters indicated where tertiary grouting was required. Grouting pressures induced a small rock failure at the tunnel heading as well as increased stresses on the tiebacks of the excavation.

Jan 1, 1997

By A. Shtiza

This literature review discusses the role of the Albanian institutions, the natural resources industry, potential investors and stakeholders in order to provide a set of indicators that can help to monitor amelioration within sustainable development principles. A map with the potential prospects of the natural resources will be a first step in identifying the further potential for exploitation. Mineral resource policies and governance, sustainable processing and supply chain as well as environmental management information system are some of the crucial tools identified, that will help to set up the indicators and quantify the achievements in environmental management in Albania. Moreover, the integration of practices that will support institutional capacity building; follow-up practices; the mainstreaming of global environment into planning; and the compliance monitoring process will additionally improve the environmental situation in Albania. Aligning business strategy with environmental policy, socio-economic analysis, environmental auditing are decisive tools in order to provide the Albanian authorities with a clear overview of the economic costs and the social benefits for sustainable development.

Jan 1, 2011

By Eugene F. Casey, William H. Hansmire, J. Ghaboussi, Randall L. Lentell, Harvey W. Parker

INTRODUCTION Construction of a major intercepting sewer in Brooklyn, New York involved tunneling in soil over several subway lines. In two instances the clearance between the subway and sewer was sufficiently close that concern was raised about the influence of the new construction. Prior to each critical crossing, analytical studies were performed which characterized the tunneling influence. It was demonstrated that with adjustments in construction procedures the crossings could be made without affecting the integrity of the subway linings. A comprehensive program of instrumentation and full-time monitoring was undertaken to ensure that any unforeseen adverse developments during crossing would be recognized. The successful crossings were subsequently made with minimal influence. Reported herein are the special construction conditions for the two crossings, the analytical simulation of behavior, and the results of monitoring on the subway linings. SEWER TUNNEL CONSTRUCTION AND EXISTING SUBWAYS The Red Hook Intercepting Sewer is a 2600 m (8600 ft) long tunnel which is part of a major water pollution control project in New York City. For clarity of nomenclature, the sewer is termed a 'tunnel' while the rapid transit structures are termed 'subways'. For routine construction, the tunnel was mined by hand with a 3.2 m (10 ft-5 in.)

Jan 1, 1981

By R. J. McGregor

The Internet has revolutionized worldwide communications. Any real or perceived mining incident or environmental spill, no matter how small or remote, can become a disaster of "biblical proportions" through the judicious use of the Internet by environmental and anti-mining groups. In addition, mining companies' own Web sites and unofficial message boards can provide plenty of additional ammunition to the anti-mining forces. This paper explores how the Internet and readily available information are used by anti-mining groups active on the Web.

Jan 1, 2001