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By T. H. Phillips

The Mission Mine is an open-pit copper mine located 18 miles south of Tucson, Arizona in the eastern foothills of the Sierrita Mountains. Mining is done on 40 foot benches using P & H 2100 shovels and 170-ton Terex trucks. Drilling is accomplished With two (2) Bucyrus-Erie 45R?s, one (1) Bucyrus-Erie 60R and two (2) Ingersoll Rand T-5?s. For secondary drilling. a Joy VCR-ISO truck mounted drill is used. The mine is currently operating 3 shifts/day, 7 days/week at 59,100 tons per day, with the mill receiving 28,500 tons per day. The management of the drilling and blasting program requires extensive record keeping in all phases of the operation. This is essential in order to evaluate different products and procedures.

Jan 1, 1988

By B. K. Mishra

Power draw of the mill has been accepted as an indicator of the performance of the mill, yet the problem of predicting power under a given set of mill operating conditions still remains to be solved. In the literature, this problem of predicting power is attributed to a lack of knowledge with regard to the motion of the charge. Here a DEM based model is used to analyze the motion of the charge. The resulting information is used to predict the power draw of the mill. A 16-ft diameter mill is simulated. A factorial design study of the variables-mill speed, lifter configuration and ball size distribution-as independent variables is taken up. The power draw as a response variable is analyzed to establish the best operating condition of the mill.

Jan 1, 1993

By Edwin A. Harre, John J. Mortvedt

Plants obtain nutrients from both air and soil. They absorb carbon dioxide mainly from the air, although some carbon dioxide may be dissolved in soil water which is absorbed by plant roots. Carbon dioxide, a gaseous form of carbon and oxygen, supplies the carbon which usually makes up 50% or more of plant structure. Growing plants use water more than any other biological substance. Plant nutrients dissolve in soil water and enter the plant via root absorption. Water is then given off into the air as the plant breathes or transpires. Water also supplies hydrogen and oxygen to plants. Plant roots absorb nutrient cations or anions by contact exchange with soil clay particles. Inorganic or mineral nutrients essential to plants are supplied through the soil. Inorganic or mineral composition of plants usually is less than 5% of their weight. In most crop-growing areas, much of this nutrition is inadequately supplied from soil reserves and must be provided by fertilizers. The role of the fertilizer industry is to provide economical, efficient, good quality fertilizers to improve or maintain soil productivity for optimum crop production. The essential plant nutrients other than carbon, hydrogen, and oxygen which often must be added to soils or plants are categorized as primary nutrients (nitrogen, phosphorus, and potassium), secondary nutrients (calcium, magnesium, and sulfur), and micronutrients (boron, chlorine, copper iron, manganese, molybdenum, and zinc). These classifications are based on quantity of nutrients utilized by plants and do not imply their function or degree of necessity. One point of major significance to the fertilizer industry is that not all fertilizer minerals contain the plant nutrients in a chemical form available to the plant. A product which may be considered a fertilizer mineral may require substantial processing or treatment before it becomes useful as a nutrient source or fertilizer.

Jan 1, 1994

Integrated mining information and process control systems can reduce information delays, enhance decision making and improve the responsiveness of mining operations to, for example, variations in market conditions, mineral grades and ground conditions. This paper examines developments in the areas of: monitoring, data analysis and diagnosis,' communications systems; integrated mining support system;, and process and machine control. It concludes that the development of a comprehensive information technology plan is fundamental to the phased implementation of these technologies. In addition, hardware and software standards and concurrent digital design and simulation practices in selected manufacturing industries are examined and concluded to have relevance to the mining industry. Integrated information and process control systems will lead to emergence of the "digital mine". Such advances in mining information infrastructure as well as mining equipment will enable mining operations to shift from mass production methods to leaner production techniques. "Lean mining" aims to enhance and accelerate cash flow over the life of a mine by focusing on reduction of' throughput times; stockpiles for volume and quality control; and wastage and rework.

Jan 1, 1995

By J. Yao

Synthetic indium-bearing zinc ferrite (IBZF) was mechanically activated by a tumbling mill. Subsequently, the behavior and kinetics of leaching zinc and indium from the initial IBZF and activated IBZF in sulfuric acid solution were investigated. The results demonstrate that the tumbling ball milling enhances the leaching reactivity of IBZF and increases the zinc and indium extractions. The reaction temperature and H2SO4 concentration have an important effect on leaching zinc and indium from the initial IBZF and activated IBZF. The kinetic model -ln(1-x) = kt was used to describe the kinetics of leaching zinc and indium from the initial IBZF and activated IBZF and to calculate the kinetic parameters. The tumbling ball milling causes a decrease in activation energy and reaction order, which indicates that the dissolution of IBZF after mechanical activation by a tumbling mill becomes less sensitive to temperature and H2SO4 concentration. For the zinc leaching, the activation energy decreases from 73.9 to 70.3 kJ/mol and the reaction order decreases from 0.72 to 0.70. For indium leaching, the activation energy decreases from 78.1 to 73.5 kJ/mol and the reaction order decreases from 0.82 to 0.69. It is found that the dissolution rates of the initial IBZF and activated IBZF are controlled by surface chemical reactions.

By R. A. Haney

The Mine Safety and Health Administration has developed a model to estimate diesel particulate (dp) exposures in underground mines. The estimate uses either in-mine measured dp concentrations or engine manufacturers' standardized emission data and through a series of calculations estimates full shift dp concentrations by applying standard engineering principles of ventilation, control technology and work cycle. This model, in the form of a computer spreadsheet, provides the mining industry with a method to estimate diesel particulate levels and determine the impact of various diesel particulate controls on occupational exposure to dp in underground mines. A detailed description of the estimator and several examples demonstrating the results are provided.

Jan 1, 1998

By B. A. Wills

Much research effort has been spent in attempting to reduce the high energy costs in grinding, but relatively little in developing methods to enhance the liberation of the minerals from each other. This paper presents some ideas on the nature and role of grain boundaries in mineral assemblies, and their influence on the propagation of cracks through the rock. It is argued that if the mechanisms of fracture are more clearly understood, crack propagation may be controlled in such a way that intergranular fracture dominates breakage, producing less fines and a higher degree of liberation.

Jan 1, 1995

By R. L. Lewis

A simple method for estimating the steady-state water quality of a pit lake is presented. The steady-state concentration of a conservative chemical constituent in a pit lake is shown to be a simple function of inflow rate, evaporation rate, and inflow concentration. An analytical method is presented for estimating the equilibrium ground water inflow rate for use in water quality predictions. The time required to reach chemical steady-state is estimated using an iterative mass balance model. Mine operators should find the methodology useful for planning and screening-level regulatory applications where conservative estimates of pit lake water quality are desirable.

Jan 1, 1998

By K. W. Morris

Of the fossil fuels used for power generation coal is by far the most variable and complex in its properties. A thorough review of the characteristics of the coal to be fired is essential before boiler design can begin. Major parameters such as heating value, moisture content and ash properties will determine not only the boiler size and configuration, but also the performance of the unit with respect to the thermal efficiency, particulate and gaseous emissions, and unit availability and reliability. An example of a review completed on a large low-rank coal deposit for a power plant will be described.

Jan 1, 1983

By Brij M. Moudgil

Flotation was introduced in phosphate rock processing in the late twenties and since then it has been an important part of the concentration process. More than two thirds of the rock produced in Florida is upgraded by the flotation process. Since no crushing or milling steps are involved in the material preparation, the flotation plant feed is coarser than in most other mineral flotation systems. During hydraulic processing of the rock, particles in the size range of -14, +150 mesh constitute the flotation feed. This size fraction is further classified by hydraulic sizers, stationary screens and vibrating screens into a coarse (-14, +35 mesh) and a fine (-35, +150 mesh) flotation feed. The flotation techniques for concentrating the fine feed as practiced by the Florida Phosphate producers have been standardized over the years, however, methods for upgrading the coarse feed differ from plant to plant. In this paper an effort has been made to present relative merits of the techniques employed for concentrating the coarse phosphate rock..

Jan 1, 1977

By A. D. Davis

Environmental impacts from acidic mine drainage are growing national concerns that are particularly acute in the headwaters of the Rocky Mountain region. In the Black Hills of South Dakota, approximately one thousand mines are inactive or abandoned, most of them in the headwaters of major drainages. This paper examines the Bear Butte Creek basin, a heavily mineralized watershed with significant historical mining impacts and a surface gold mine permitted in 1997. The watershed loses its surface discharge to swallow holes in the karstic Madison Limestone. The integrity of the aquatic ecosystem was monitored with a suite of site-specific bio-indicators. Stream surveys covered the entire reach of Bear Butte Creek from near its headwaters to the swallow holes in the Madison aquifer. Data from the stream surveys, water-quality sampling, and bio-indicator surveys clearly showed that water-quality impacts are limited mainly to Strawberry Creek and to the area of Bear Butte Creek near and downstream of the town of Galena.

Jan 1, 1999

By G. Meschke

"This paper reports on computational and experimental research, performed at the Collaborative Research Center “Interaction Models for Mechanized Tunneling” at Ruhr-University Bochum, Germany. Research covers a broad spectrum of topics relevant for mechanized tunneling in soft soil conditions. This includes advances exploration methods and models for the characterization of the in-situ ground conditions, the interaction of the face support and the tail gap grouting with the porous soil, multi-scale models for the design of fiber reinforced segmental linings with enhanced robustness, computational methods for the numerical simulation of the tunnel advancement, the soil excavation and the material transport in the pressure chamber, logistics processes and risk analysis in urban tunneling.INTRODUCTIONMechanized Tunneling has proven itself as an economical and flexible construction method that continues to undergo a dynamic evolution process. Shield diameters continue to increase, and the application range of tunnel boring machines is being extended to an ever-increasing variety of geotechnical conditions. In order to maintain economic viability and to ensure an environmentally friendly construction process, realistic and reliable numerical models are required in order to make informed decisions during planning and construction. To provide a reliable numerical prognosis, it is necessary to accurately assess and understand the interactions between the components involved in mechanized tunneling with the surrounding site, the ground, and any pre-existing structures. Heterogeneous geological conditions and often only approximated ground parameters create, in contrast to other engineering projects, special demands. This necessitates new insights to new problems that can only be effectively solved through truly interdisciplinary research. To address these challenges, the German Research Foundation (DFG) has established the Collaborative Research Center “Interaction Models for Mechanized Tunneling” (SFB 837) at the Ruhr-University in Bochum in 2010. Collaborative Research Centers are interdisciplinary scientific research groups in which cooperative research is conducted under the umbrella of a central research theme. With a research budget of ca. 10 Million Euros for the second 4-year funding period, and a research team composed of 13 project leaders along with approximately 35 scientific assistants the SFB 837 is currently one of the largest research groups conducting fundamental research in tunneling related topics worldwide.RESEARCH TOPICSThe research topics of the SFB 837 encompass a number of relevant planning and construction related aspects in mechanized tunneling (Figure 1). These research themes are each supported by computational models and laboratory investigations and are all included in an SFB overarching Tunnel Information Model (TIM). Interaction groups integrate and combine the results of different submodels through prototypical cause-and-effect relationships, and through the analysis of the Wehrhahn metro line (WHL) project in Düsseldorf, which has been adopted as the reference project for the SFB 837."

Jan 1, 2016

By Patrick Sullivan

Over the past few years, successful operations for processing phosphates employing the Grate-Kiln System have been achieved. Control and instrumentation philosophy followed in these installations are described and analyzed. Concepts utilizing digital techniques and computer systems appropriate for similar installations are also discussed.

Jan 1, 1967

By W. R. Boehme

The test work was done in two parts. In Part I, five 6 x 16 mesh activated coconut shell carbon samples made by four different manufacturers were evaluated as to their gold loading rate and total gold loading. The five carbon samples tested are not identified by manufacturer and are simply designated as Types A through E. Then from the carbons tested, a suitable highly active carbon was selected for subsequent studies on impurity effects upon loading, Part II. Test Procedures The procedures and tests descriptions are given for the ultimate gold carbon loading tests and the dynamic gold carbon loading tests.

Jan 1, 1983

By William C. Ellis

Underground water is part of a continuing hydrologic cycle, which involves all elements of water occurrence. All groundwater of economic importance is in process of movement through a porous rock stratum from a place of intake or recharge to a place of disposal. Groundwater moves and is contained in fractures in the rock and/or in intergranular spaces of porous formations. Where there have been no water developments by man, groundwater is in a state of approximate equilibrium and the forces of replenishment and discharge are in balance. Thus, groundwater, unlike other mineral resources, is constantly being replenished in most areas at a rate which is measurable and which is important in the planning of its utilization. As illustrated by Figure 1, replenishment of groundwater supplies results from the direct penetration of rainfall through the soil to the water table, by seepage from surface streams or ponds, and/or by subsurface movement from an adjacent groundwater body. Under natural discharge conditions, water is commonly consumed by transpiration of trees and other types of vegetation, by flows from springs, by evaporation from shallow depths below the surface, and seepage into streams that traverse the area.

Jan 1, 1964

By T. A. Moss

The installation of equipment and structures at mines often requires the evaluation of unique loading and operating conditions. Consideration of these unusual features is required throughout design and construction and into operation. The necessity for employing sound civil, structural and mechanical engineering techniques to the design of structures and equipment is well understood. However, the influence of geotechnical factors on the overall behavior during construction and operation of these facilities is less appreciated. Mine operators routinely perform exploratory drilling for the purposes of defining ore deposits. These exploration activities can be extensive and often include provisions for assessment of subsurface conditions as they relate to the mining operation, i.e., requirements for ground support. All of these factors are important to the economics of the mine and are well justified. Surface facilities are provided to access and service the mine and they play an important role in the successful development and operation of a project. Headframes, hoist foundations and shaft collars, in particular, are examples of unique installations encountered at underground mine sites. The design and above surface behavior of these facilities can be analyzed with the usual fundamental engineering practices employed throughout the engineering professions. This requirement during the project development is understood and adopted. Unfortunately, near surface exploration for the purposes of assessing soil and rock conditions for foundations are often given a reduced priority and less consideration. This paper is aimed at providing an outline into the benefits and importance of performing such explorations and to provide a brief discussion of the merits of such an approach. References in the paper relate particularly to shaft headframes, hoists and shaft collars but the issues raised apply equally well to other installations of a similar nature, e.g. milling equipment.

Jan 1, 1992

By Aurel Goodwin

I chose the title "Let's Clear the Air" for this afternoon's presentation because it has two meanings, the literal and the figurative. Most of you know what MSHA is. Most of you know what MSHA does. And, for the most part, most of you know why. What I hope to accomplish today is to "clear the air" around our health standards, to clarify for you how MSHA views its congressional mandate under Title I Section 101(a)(6), (7), and (9) of the Mine Safety and Health Act. Asbestos, silica, radiation, noise, welding fumes, carbon monoxide, lead, hydrogen sulfide, nitrogen dioxide - the list of physical and chemical hazards encountered in the metal and nonmetal mining industry is as diversified as the industry itself, possibly even more so. In addition, miners are often exposed to several of these health hazards simultaneously.

Jan 1, 1980

By Larry Cook

During the past year the news media has come in for its share of criticism. Some of it, without doubt, is justified. Much of it, like that which has been leveled against some of the rest of us, is not. We can sympathize with the newspapers and magazines, the radio and television stations. Like the coal industry, which I represent, they are a part of the free enterprise system. They depend upon advertising for their existence, and advertisers patronize those media which reach the most people interested in their product. The various news media are therefore In avid competition for circulation. Although they do have an unquestioned influence on the public, they are primarily a reflection of the public and it is in this context that we will consider them. Granted that this reflection is sometimes a bit distorted, let us admit that any subject which does not strike a responsive chord In the public will soon be dropped by the media.

Jan 1, 1970

By David M. Parkes

Geology is frequently complicated, hence only more regular deposits are mined. Coal is generally thick, often steeply pitching and usually soft or well-cleated. Due to competition from open-pit mines, only two underground mines are operating, McIntyre and B.C. Coal. Several other mines are being planned, the method being evenly divided between hydraulic, longwall, and room and pillar. McIntyre mines in the flat part of their formation (up to 20 degrees) uses continuous miners and shuttle cars in the 3m and 6m seams. This company is considering a retreating longwall face. B.C. Coal operates a hydraulic mine in a 16m thick seam dipping at 10 to 55 degrees with a productivity of about 20 tonnes per manshift.

Jan 1, 1982

By J. McCreedy

The Ontario Division of The International Nickel Company of Canada, Limited, operates five underground mines and one open pit on the rim of the Sudbury Basin located in the Province of Ontario, 230 miles northwest of Toronto. Four of the mines, Frood-Stobie, Creighton, Murray and Garson, lie on the South range of the Basin within a 10-mile radius of the City of Sudbury; the fifth mine, Levack, is on the North range, about 30 miles northwest of the city. The ores are mined primarily for nickel and copper, the principal minerals being pentlandite and chalcopyrite. Other elements recovered from the ores in varying quantities are platinum, palladium, ruthenium, iridium, rhodium, cobalt, selenium, tellurium, iron, sulphur, gold and silver. In 1962, the total underground ore production was over 10,800,000 tons which was mined mainly by blasthole and caving methods with the remainder by cut-and-fill, square set, and undercut-and-fill techniques.

Jan 1, 1964