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By J. Castaneda, J. Schmidt

"INTRODUCTION Chino is an open-pit copper mining complex faced with intricate material routing requirements. Historically, this was challenging at the mine, in part because the shovel dig plan, haul plan, and dump plan were prepared completely separately. The mine now uses an integrated workflow for faster evaluation of schedules, which facilitates preparing balanced cutoff grade-to-equipment requirements, supports better mineral production, and improves schedule viability, while considering operational implications. Located in the state of New Mexico, Chino is one of nine Freeport-McMoRan mining operations in North America. This presentation discusses the benefits of implementing an integrated approach to tactical mine planning, and shares practical examples that were learned as Chino implemented an integrated tactical planning method. This includes improvements in completion time for preparing a schedule, minimal risk from manipulating Excel macros, data integration required to make short-term planning decisions, and better understanding of the mine plan’s effect in relation to the business’s key performance indicators. Ultimately, the integrated approach to tactical mine planning at Chino has led to production forecasts which are more achievable and reduced planning and execution variance. PROJECT OVERVIEW Chino mine is a porphyry copper deposit wholly owned by Freeport-McMoRan, the largest publicly traded copper producer in the world. Chino mine is located in Grant County, New Mexico, a short distance east of Silver City. Ore material mined from the pit today includes oxides, primary sulfides, and secondary sulfides. The mineralized material is sent to a mill, with a rated throughput of 42,000 tons per day, or to ROM leach pads with variable dumping capacities. At Chino, the short-range objective is to maximize total copper pounds sent to the mill, but no fixed cutoff grade accomplishes this for all periods. Instead, 12 different material classifications, including four sulfide classes that can feed either the mill or other destinations, and 38 cutoff bins, are aligned with the needs from operations, leaching, and the concentrator to create a schedule. Cutoffs vary from one week to another to cope with a highly intermittent ore body."

Jan 1, 2018

By K. S. Eric Forssberg, T. V. Subrahmanyam

The present paper deals with the important technological developments in gold processing and where possible, the data is presented in the form of tables. Gold processing methods have evolved to such an extent that low grade and complex ores once considered uneconomic are now becoming viable. Constant efforts are underway to innovate technologies in order to improve the efficiencies and cut down the capital and operating costs. The methods are discussed.

Jan 1, 1988

By L. P. Meade

The need to feed an established talc mill from a crude ore source located closer to the mill prompted the 1986 drilling of a previously mapped, talc-carbonate deposit. This talc-bearing rock had never been considered a potential source of crude talc ore because of the high carbonate content and other deleterious minerals observed in outcrops. Selective mining, in-pit grade control and creative processing have allowed this deposit to be developed into an ore body. By definition, an ore body has to be a source of positive cash flow. With industrial minerals, this is determined as much by market acceptance as by ore tenor.

Jan 1, 1994

By A. F. Klebanov, K. N. Trubetskoy, M. Yu Khoudine, V. L. Postnikov

The information system of monitoring of mine receive layouts is being created In the "ROSUGOL" Company for the prompt analysis of the state-of-the-art of mining operations at under- ground and open cast mines of the Company, rapid and effective decision-making and elaboration of recommendations on the basic directions of enterprise development. The data bank storing the digital mapping and attributive information describing the actual background of mining operations at the enterprises of the Company is the core of the system. The Oracle database management system and the ARC1 INFO geographic information system have been chosen as basic software packages for the Project realisation. The updating of the information will be performed on a regular basis via the transmission of actual digital data on under- ground and open cast mine layouts In ARCIINFO conversion to the central office of the "ROSUGOL" in Moscow. Centralised storage of digital mapping and attributive data, database administration and navigation is effected with the Oracle software package. Access to the data in the operation mode with an interactive display map will be effected with the use of the local computer net of the "ROSUGOL."

Jan 1, 1996

By Jonathan J. Owen

We will describe modifications to air-sparged hydrocyclones (ASH) that enhance collisions and reaction of wastewater contaminants with sparged gas. These new ASH-based reaction chambers are combined with flotation tanks that are designed to optimize separation of bubbles and particles from water. In combination, these systems have achieved unprecedented removal of contaminants from industrial wastewater and process water while requiring smaller footprints with lower capital and operating costs. Real-world examples of chemical and nonchemical water treatments that demonstrate the outstanding flexibility and applicability of these systems are shown. Design enhancements that resolve the operational problems of traditional ASH are discussed.

Jan 1, 1999

By G. J. Grott

Direct Production Costs for Solar Sa 1t approximate the trucking cost for 160 Km. Operations near markets appear unusually attractive at first look. However, many desert operations have been plagued by dust storms yielding salt too high in insolubles for most uses. This paper relates the history of a successful operation in a dust storm area. Saturated brine from the solution mining of LPG storage caverns is evaporated in solar ponds yielding 99.95% sodium chloride (dry basis). Purchased energy is one-eighth that of vacuum pan operations. Production scale tests have proved it works at another desert location using a more complex brine. A new approach for refining soluble salts at ambient temperatures is demonstrated by bench scale and pilot work. Again, savings in purchased energy exceed 80%, even when temperatures are raised to reduce refining time.

Jan 1, 1988

By H. T. Mulryan

Talc is used as an essential ingredient in a variety of plastics applications ranging from polyester body patch compounds through polypropylene automotive, appliance and household furniture components to high performance parts made from liquid crystal engineering resins. This paper focuses on polyolefin applications, the three-tier market for talc in polypropylene, the effects of various tales in typical compounds and trends in each market segment. Emphasis is given to emerging markets, examples of which are polypropylene compounds that mimic higher cost resins, and polyethylene films. Customer requirements for tales for these purposes are discussed.

Jan 1, 1994

By Robert J. Watters, Peter C. Kelsall, Joseph G. Franzone

Two separate studies investigated the compressive strength of basic igneous rocks and its relation to index properties such as porosity, density and soundrave velocity. The rocks tested were weathered dolerite from S. W. England and vesicular lavas from California. In both cases strength was affected considerably by porosity. In the dolerite, strength was also affected by fissures (microcracks) which were formed in the parent rock by shearing and later accentuated by weathering. While test results show that porosity, density and sound velocity are not reliable indices of rock strength, these properties are useful in interpretation of strength test results. Index testing can be used to classify samples according to similar behavior and to recognize the influence of fissures.

Jan 1, 1986

By R. Karl Zipf, Z. T. Bieniawski

Based on the premise that understanding the fundamental mechanics of fine fragment formation in coal will lead to reducing coal dust problems in mines, a thorough study of the mechanics of crack propagation in coal was undertaken. Two approaches were considered in an attempt to understand and quantify the fracture process as it relates to fine fragment formation. In one approach, theoretical models are used which describe the size of the fracture process zone which may relate to the amount of structural damage and fine fragment formation on the new crack surface. The other approach is based on the relationship between crack tip stress intensity and new surface appearance for mixed mode crack propagation. Preliminary observations with a scanning electron microscope support the premise that fine fragment formation is related to fracture surface appearance and fracture initiation conditions. An experimental program designed to supply the input parameters for these approaches is presently underway. The experimentation features mixed mode fracture toughness testing, using a special mixed mode testing rig, and fracture velocity measurements with a crack propagation gage. The interpretation of this data via the approaches discussed will provide further under- standing of the mechanics of fine fragment formation in coal.

Jan 1, 1986

By Y. M. Jiang, D. W. Park, S. M. Lee

A vast majority of longwall operations in the US use shield-type hydraulic supports to provide ground control along the longwall face. The three-dimensional, finite-element technique combined with a progressive failure approach was utilized to simulate interaction between shields and surrounding strata and determine various loading conditions. In addition, a separate finite-element model of the shield structure was made to study responses of each longwall shield to the different loading conditions. Shield responses under various loading conditions and the shield characteristics, such as shield stiffness, the ability of resisting horizontal forces, and the effect of shield height, were studied based on the results from finite-element analyses. The results can provide the basis of effective shield design and be used for evaluation of the shield performance. It is suggested that a technique incorporating the finite-element method be developed to evaluate real-time shield performance for the purpose of effective ground control.

Jan 1, 1993

By R. A. Hodge, J. W. Murray

By an order of the Executive Council of the Provincial Government dated January 18, 1979, a Royal Commission was established under the Public Inquiries Act to: 1) Examine the adequacy of existing Federal and Provincial requirements for the protection of the health and safety of workers associated with exploration, mining and milling of uranium in B.C. and for the protection of the environment and of the public. 2) Receive public input on these matters. 3) Make recommendations for setting and maintaining standards for worker and public safety and for the protection of the environment as a result of the exploration for the mining and milling of uranium ores. At that time,and at the present time in British Columbia, no uranium mines were, or are, in operation. Exploration at a number of sites was under way and one deposit, the Blizzard deposit, with estimated reserves of 1.92 million tonnes containing approximately 4.74 million kilograms of U308 was at an advanced stage of exploration. With our Terms of Reference, and because of the diverse geology of the western Cordillera which could potentially host a broad variety of uranium, deposit types, the Commission was faced with the task of considering environmental and health protection necessary for the potential development of [any] kind of uranium mineralogy situated in [any] of the environments found in British Columbia. Over the past 17 months since that time, much has transpired, culminating in the February 27, 1980 Provincial Government announcement of a seven year moratorium on exploration, mining and processing of uranium coupled with the termination of our Inquiry before completion of the hearings. The Government sebsequently modified its decision to terminate the Commission completely, deciding instead to stop the hearing but allow time for the Commission to gather in the work that had been initiated

Jan 1, 1980

By G. B. Misra

Though installations of main mine fans vary widely, the commonest installation is of a surface exhaust fan connected to an upcast shaft some distance below its collar by a horizontal fan drift bending sharply. downwards near its junction with the shaft. The junction of the fan drift with the shaft often causes considerable shock pressure loss if not properly designed. In one of the major coal mines in India circulating 180 m3/s of air through the mine a pressure drop of 229 Pa out of the total fan pressure of 568 Pa occurred at this junction while in a smaller gold mine circulating 9.4 m3/s it was 147 Pa out of a fan-drift pressure of 382 Pa. With larger mines circulating larger volumes of air, ill designed fan drifts can lead to considerable wastage of the power of ventilation. Shock loss at the junction of fan drifts with exhaust shafts depends on (1) the angle of deflection of the bend, (2) sharpness of the corners (both inner and outer) at the junction, (3) the degree of contraction of the flow-stream which depends on the cross- sectional area ratio of the shaft and the fan drift as well as the amount of leakage through the shaft collar. It must be noted here that the friction pressure loss in the bend is negligible compared to the shock pressure loss.

Jan 1, 1980

By Alfred Jr. Petrick

Modelling of cash flows and calculation of net present value of rate of return over the expected life of a mine/processing unit continues to be the accepted basis for mineral investment decision-making. The computer and spreadsheet programs have greatly improved ability to perform sensitivity and risk analysis, hence our ability to deal with key analytical problems. These problems of cash flow analysis result from the necessity of forecasting an uncertain and risky future. Cash flow models begin with the critical assumption of a "design basis", then integrate all of the variables relevant to the investment decision including forecasts of price, cost, taxation, financial conditions, and company strategy. Alternate "scenarios" portray possible future outcome of the investment decision. The potential for straying from reality is enormous. The computer has eliminated the time consuming hand calculations from the cash flow analysis, but the analyst still struggles with the risk of trying to predict "how the project will really turn out".

Jan 1, 1991

By Y. C. Kim, I. S. Roditis, P. K. Medhi

The strongly skewed grade distributions and the need to estimate the local recoverable reserves in a selective mining environment are the two problems that ordinary kriging (OK) cannot easily handle. With the recent introduction of the non- parametric, distribution-free technique of indicator kriging (IK), the above problems can be solved. This paper describes the result of performance evaluation of IK in an open-pit gold-silver deposit. For performance evaluation, the predictions of local recoverable reserves using IK were compared with the actual reserves based on blasthole information. The IK estimator, although a bit optimistic (or overestimating), performed very well in predicting the total recoverable ounces of gold from each panel on a test bench. The OK estimator was also used to try to predict local recoverable reserves, by treating each panel as either waste or ore, depending on the panel's average grade. Under this criterion, OK was found to be quite biased and pessimistic (or underestimating).

Jan 1, 1988

By Hill McDonald

Sand and gravel deposits may be explored by many different methods. The methods used by The Standard Slag Company are primarily two in nature. One is using an auger which is limited in depth by various soil conditions. The other is a heavy wall dry sampler and a heavy wall wet sampler. The heavy wall dry sampler takes continuous uncontaminated samples up to seven inches in diameter. The heavy wall wet sampler takes continuous uncontaminated samples up to six inches in diameter. For us, the maximum depth of the heavy wall samplers has been two hundred fifty feet of which one hundred feet was above the water table and one hundred fifty feet was below the water table.

Jan 1, 1972

The problems of toxic, noxious, and explo¬sive atmospheres caused by gases and dusts are certain special environmental considerations in underground mining. Some other problems unique to underground mining are design of stable structures in the strata and their support, lighting the workings, and control of noise in confined spaces. These affect the health and safety of the workmen and deserve critical analyses. Some of the most important environmental parameters of underground mining are summarized in Table 1. The list is not exhaustive but illustrates the scope of environmental planning in underground mining. This chapter will discuss the use of computers and computer models in mine atmospheric environmental planning.

Jan 1, 1979

By T. H. Udayashankara

Soil pollution, a very serious environmental problem, has been attracting considerable attention in recent years. It is now generally recognized that land as a component of the environment deserves the same attention and protection as water and air. This recognition has arisen perhaps because of increased incidents of land pollution, the scarcity of land, and increased awareness and concern about long-term effects of land pollution on terrestrial and aquatic eco-systems and on ground water quality. Contamination of land results from a wide range of human activities, including industrial discharge process, disposal of wastewater and agriculture. The environmental impact of exploration, production and refining of crude oil is a major concern in developed and developing countries. Because of the known adverse effects of petroleum hydrocarbons on soil ecology and fertility there has been growing interest in the development of efficient technologies for the remediation of contaminated land, with a view toward making it available for further use. Crude oil is a natural product and as such is susceptible to degradation by naturally occurring micro flora. Bioremediation has become an important method for the restoration of oil-polluted environments. A bench scale study was conducted to evaluate the bioremediation technique in treating soil contaminated with transformer oil. The steps involved in this study are: (1) Preparation of contaminated soil, (2) Extraction of PAHs and PCBs from contaminated soil, (3) Treatment of contaminated soil in slurry batch reactor, and (4) Analysis of PAHs and PCBs by gas chromatography technique. The performance of reactor was assessed by measuring parameters like COD, PAHs and PCBs. The study was con-ducted for six different pulp densities ranging from 20% to 40%. The maximum removal of PAHs and PCBs was observed for 20% pulp density.

Jan 1, 2008

By R. Hogg

The factors which control the dewatering of fine coal by gravity/centrifugal drainage and by gas displacement (vacuum/hyperbaric filtration) are evaluated. A generalized model is presented and used to describe dewatering kinetics and to establish dewatering limits. Applications to the design of dewatering systems for fine coal dewatering are discussed.

Jan 1, 1995

By Patzen Wu

The Hai-Shan No. 1 Coal Mine, located in northern Taiwan, is one of the typical coal mines on the island which, limited by natural condition, are mostly small in scale. With the advancing longwall method, the mine is now winning a seam, 80 cm thick, at a 32° dip, with a working depth of 824 m below surface. The annual output is about 50,000 mt of clean coal. At the working gallery, the virgin rock temperature may go up to 46°C, difficult to be brought dam to n acceptable level: because .of the tropical climate with high intake temperature and high humidity. Besides, at this depth, the intake air that goes down the long inclined shaft generates considerable heat due to autocompression. The mine is ventilated by a set of axial-flow fan with 38 m3/S of intake air at 2.2 KPA WG. With this volume of air, the temperature at the working-face is usually above 30°C WB. Appreciable lowering of the temperature is not expected even with an increased volume of ventilated air. For this reason, decision has. been made to try the installation of a pilot underground refrigeration unit near. the lowest gate road to cool the intake. air. from 32°C WB to 28°C WB which seems acceptable to on-the-spot workers exerting heavy physical labor. The experimental unit is designed for carrying away a total heat load of 90 Kw. The capacity of the unit is 200 Kw. The unit consists of a compressor, an evaporator, a condensor and a motor. The heat rejection is done in a cooling tower. Chilled water is circulated from the evaporator to the cooler by insulated pipes. The cooler consists of 90 Kw-coils with two fans and forces air by flexible ducting onto the working face. This paper examines mainly the effect of this additional reduction of working temperature, on working efficiency of the workers. Another aspect of this experiment is to evaluate the overall economy of underground refrigeration in small-sized coal mines under tropical condition. The success of such an experiment may lead to wider application of refrigeration to render many of the deeper mines economically workable.

Jan 1, 1980

By Jasna Jurjovec, David W. Blowes, Carol J. Ptacek

At the Kidd Creek site, natrojarosite residue, derived from the zinc refinery circuit, is mixed with mill tailings before final disposal in the tailings impoundment. Column experiments were conducted with fresh unoxidized mill tailings and a mixture of tailings containing the natrojarosite residue. Acidic water, simulating mine drainage water, was pumped through the columns. The effluent water geochemistry was interpreted with the assistance of MINTEQA2. The experimental results suggest that the effluent water pH was buffered by a series of acid neutralization reactions. The release of metals, including Cu, Pb and Zn, was affected by pore water pH, Eh and mineralogy of the tailings material.

Jan 1, 2000