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By C. Patrick, T. Combs

The purpose of this paper is to provide a method for analyzing the sequencing of mining production processes and predicting the effects of any planned changes. Included is a description of the development and utilization of a project-scheduling simulation that combines analytical scheduling with stochastic-activity durations. The simulation is demonstrated in two realistic examples: a longwall face-to-face transfer sequence and the effect of varying advance rates on longwall development sections. Statistical data that can provide a basis for more informed production decisions are generated in the form of project activity/path criticality and project-duration distributions. In both examples, a quantitative risk assessment, regarding subjective decisions in underground production sequencing, is presented.

Jan 1, 1996

By S. D. Thompson, L. Adler

This study reviews and analyzes the empirical methods available for designing the capacities of coal mine gathering belts. The analyses lead to recommendations concerning the application and implementation of each empirical method. Operations research techniques, mainly simulation models, are also briefly mentioned, and a few recommendations are made concerning their selection and application. The objective of the study is to provide a reliable basis for the practicing engineer to properly select, apply, and implement a capacity design method.

Jan 1, 1988

By K. A. Natarajan, M. K. Yelloji Rao

Significance of grinding media wear and its effect on chalcopyrite flotation are discussed. Laboratory marked ball wear tests were conducted grinding chalcopyrite ore and quartzite dry, wet, and with collector added during grinding. The effects of oxygen and nitrogen on ball wear were evaluated by the addition of chalcopyrite mineral while grinding quartzite. The effect of dry and wet grinding on chalcopyrite flotation was also studied. Results show abrasive wear is greater in quartzite grinding than in grinding chalcopyrite. Oxygen increases the corrosive wear of high carbon low alloy steel balls in the presence of chalcopyrite ore. Chalcopyrite flotation was retarded due to wet grinding in the presence of oxygen. Though collector reagent increased the media wear, it improved the flotation of chalcopyrite. Probable electrochemical reactions encountered in a grinding mill are outlined.

Jan 1, 1991

By J. Davitt McAteer

Improvements in the control of coal mine dust have occurred over the past 25 years. Simultaneously, dramatic improvements in coal mine production technology have occurred, particularly at mines where longwall systems are in use. Production rates of longwall systems have quadrupled since 1978, and dust generation on these systems has significantly increased. However, technology to address control of the resulting increased levels of respirable dust has not kept pace, and many high-production longwall sections continue to experience problems with respirable dust control. This paper seeks to enlist the entire mining community in the effort to resolve the health problems presented by excessive levels of respirable coal mine dust, particularly on longwall systems. These systems are expected to increase in number and length, and to generate increasingly higher levels of dust as production rates of these systems continue to rise.

Jan 1, 1995

By Kotaro Ohga, Kiyoshi Higuchi

In our laboratory, a new detection system using smell detectors was developed to detect the spontaneous combustion of coal and the combustion of other materials used underground. Laboratory experiments were carried out on several kinds of coals, including South African coals, and machine oil, wood and rubber used in belt conveyers. The following results were obtained: 1) Spontaneous combustion of coal can be detected earlier by smell detectors than by conventional CO detection methods. 2) There were no differences in the results using different kinds of coal. 3) Combustion of other materials can also be detected earlier by this system than by conventional detectors for gas and smoke. 4) Use of this detection system enables one to discern the source of the combustion gases, whether it be coal, wood, oil or rubber.

Jan 1, 1995

By C. J. Johnson, C. J. Bise

Abstract - As the US coal industry moves into the next century, it is becoming more apparent that the effective application of new technology is the only way it can remain competitive in the energy marketplace. Examples of this emphasis are with us today in such diverse areas as face- ventilation and excavation-equipment applications. The focus of this new technology is directed toward improvements in health and safety, cost control, and productivity. Room-and-pillar mining accounts for approximately 68% of the nation's underground coal production; this percentage is not expected to decrease markedly in the near future. As such, this paper analyzes the impacts of the changing techno- logical climate on future room-and-pillar operations by comparing a base-case section (current) to three scenarios incorporating new or emerging technology. A microcomputer-based comparative analysis will reflect the changes in section production and costs.

Jan 1, 1990

By R. Haecker, S. Gupta, P. Somasundaran

Rock disintegration processes are usually inefficient and costly operations in mineral beneficiation, mine development and oil well preparations. Thus, there is a strong need for improving the energy efficiency of unit operations such as drilling and comminution. The effects of selected cations and anions on drilling efficiency in a hard rock formation (Dakota Sandstone) were studied. The zeta potentials and the tensile strengths of the drilled samples were measured under similar chemical conditions. The chemicals tested included MgCl2, Na2CO3, AlCl3, NaCl and Dodecylammonium chloride. The results indicated that drilling rates can be enhanced or retarded depending on chemical conditions such as the solution pH and the type and concentration of reagents. Drilling data are correlated with mechanical (tensile strength) and interfacial (zeta potential) properties of the rock formation. The mechanisms involved are discussed in light of Rehbinder's and Westwood's theories.

Jan 1, 2000

By M. J. Virnig, B. D. Boley, G. A. Wolfe, J. M. W. Mackenzie

A flowsheet for the recovery of nickel and cobalt from laterite ores was developed. The flowsheet involves acid leaching followed by hydroxide precipitation of the metal values and then releaching of the hydroxide cake with ammonia. Investigations of the chemistry of extraction of nickel by LIX® 84-I and a developmental reagent, XI-84-IT, along with the physical properties of the organic phases are described. Based on these investigations, suggestions with regard to design of a solvent-extraction plant and operating conditions were made.

Jan 1, 2002

By Philip L. LeHoux

In recent years, much work has been done to explain the nature of the gold-carbon adsorption mechanism. The benefits of a sound theoretical basis has the obvious application to gold adsorption and elution industrial processes. Unfortunately, the lack of a clear agreement on the mechanism has provided no clear direction towards process innovation and optimization. Jones' (1989) work has gone a long way towards clarifying the specie of gold adsorbed (and thus the chemistry required to remove it). Since the development of hot caustic and cyanide elution, the kinetics have been accelerated by the application of pressure to increase elution temperatures beyond the boiling point at atmospheric pressure. However, the traditional reagent content of 15 g/L NaOH and 5-10g/L NaCN has remained largely unchanged. This is in spite of work that has shown that the presence of cyanide is not required for the elution process to take place (Adams, 1986; Adams; 1989; Jones, 1989). Adams (1989) has also compared NaOH elution rates with and without cyanide. He found improvement with the use of cyanide and a synergistic effect with the use of both. Others have found no difference in overall extraction (Jones, 1989

Jan 1, 1990

By Eric K. Albert

Computer oriented simulation techniques can be effective in the design and analysis of complex mining systems. In fact, a number of computer software products are available for mine systems simulation. However, previous models have tended toward being either data-intensive and deterministic, or data-limited and highly stochastic. The need for a fully integrated package with a simplified user interface has never been more apparent. In this paper, the design of a surface mining simulation model documented in Albert (1986) is described. The basic features of the surface mining system and their counterparts in the simulation model are discussed. The methods and algorithms used to implement these subsystems are presented. Considerations of information management and software design are illustrated, especially as they apply to the application of the package by a mining engineer. An example is provided to demonstrate the concepts embodied in the model and to show how a surface mine is simulated from mine parameters.

Jan 1, 1989

By I. Yaniv

The magneto-hydrostatic method can be used today to separate slightly magnetic or non-magnetic particles according to differences in their specific gravities and magnetic susceptibilities. The classical approach is to effect stratification prior to separation. This paper discusses some of the significant parameters which bear on the design and pattern of the expected stratification in the separation cell. As the characteristics of the magnetic field, and consequently those of the magnetic forces, are determined by the geometry of the poles, this subject is treated first. In this context a new approach, whereby the range of stratification is extended, using positive as well as negative gradients, is presented. Finally, the effect of the relative size and shape of the particles on stratification is discussed.

Jan 1, 1978

By David G. Hammond

INTRODUCTION Previous papers and discussions at this conference have already covered the subjects of identification and nature of risks, allocation of risks and contractual arrangements. In this portion of the conference, in the light of topics already covered, we will consider how to minimize risks and how to mitigate losses. Webster defines mitigate as "to make less severe or painful", an apt definition for our purpose! RISK MANAGEMENT POLICY The first thing that must be said about risks, especially in construction, is that they exist and that they don't necessarily fall alike on the just and the unjust. Some risks, i.e., some kinds of risks, must be recognized as inevitable in engineering and construction and therefore must philosophically and realistically be accepted as part of situations to be dealt with. Dealing with means minimizing, covering, and sharing of risks and doesn't mean merely passing off the risks to someone else. While some risks can be avoided, for example, whether the structure will fall down or the excavation will cave in, risks management primarily deals with: A. minimizing risks---whomever risk it may be B. equitable sharing of those risks among the participants.

Jan 1, 1979

By Jerry Grott

Southwest Salt Company is solution mining the Luke Salt Body of probable late Miocene age. The discovery hole, from which the first core was recovered, was drilled in 1968. The deposit was encountered at a depth of 880 feet, and the bit was still in salt at the bottom-hole depth of 4,500 feet. The solar ponds, developed on land formerly dedicated to agriculture, have an annual capacity of about 90,000 tons. Because land values are very high, mining rates and procedures are governed by the need for near-saturated brine to minimize land requirements. Because of the frequency of dust storms, the salt operation uses a unique wet-harvesting method. Most inventory is kept in the ponds under brine and harvested only a few days before shipment. Studies of the nature of crystal growth and the distribution of windblown and brine impurities led to the development of procedures for processing salt of high chemical purity and low insolubles content. Chemical purity exceeds that of most salt produced in fuel-fired evaporators. Salt is shipped from Phoenix as tar east as west Texas and as far west as central California. Occasional shipments have been made to Hawaii and Alaska.

Jan 1, 1987

By T. J. Harvey, W. van der Merwe, J. Joubert

GeoBiotics, LLC and Kumba Resources (Pty) Ltd are jointly developing the GEOCOAT® heap bioleaching technology and downstream processing technology for recovery of zinc from tailings at the Rosh Pinah Mine in Namibia. This paper outlines the development of a computer simulation for the bioleaching of sphalerite and the downstream processing. Computer modeling has shortened the product development cycle by allowing many flowsheet scenarios to be analyzed negating much of the expensive and time consuming laboratory testing. A model was developed using the Limn® system which is an Excel® Add-In flowsheet drawing and solution engine. Given that most engineers are familiar with Excel® this software is extremely easy to use and has less hidden calculations making model verification much easier.

Jan 1, 2003

By Gerrit V. R. Goodman, Edward F. Divers, Charles D. Taylor

Future mining systems will possess the ability to cut from crosscut to crosscut where advances could exceed 30.5 m (100ft). However, limitations arise when ventilating such mining systems. In deep advance mining, there will be no workers at the face to manually advance ventilation tubing or curtain. Additionally, traditional methods provide no means for maintaining face ventilation after the miner backs out. Problems such as these have suggested the need for innovative ventilation methods compatible with deep advance mining systems. The Bureau of Mines is currently considering a number of innovative ventilation schemes. One such method is the use of a jet fan to ventilate a deep cut. A jet fan is simply a freestanding fan using little or no ducting to direct the ventilation flow. Previous testing in large metal-nonmetal mine entries showed that jet fans provided adequate face ventilation for deep advances in large headings. Current testing will determine the application of jet fans in ventilating smaller coal mine entries. Another approach considered compatible with deep advance mining will use either exhausting or blowing tubing that can be remotely extended from crosscut to crosscut. During the mining cycle, such a device would extend automatically as the miner sumps into the face. The Bureau of Mines is considering several different operating designs using this tubing.

Jan 1, 1991

By Alexander N. Winchell

"The wash ore area on the Mesabi iron range covers a regionof the iron bearing formation extending from Grand Rapids on the west to the Hibbing district, about forty miles eastward. Not all of the developed ore bodies are of wash structure; some are of such grades that they can be shipped direct as merchants able ore. It is safe to say, however, that 65 per cent of the ore is of a possible wash structure and of too high a silica content to be classified as merchantable ore. The increase in the number of washing plants completed each year on the western Mesabi shows that ,the product must be of a structure desirable for furnace operation. The following is a list of plants which were . in operation, under construction, or with plans completed, at the end of 1918:"

Jan 1, 1920

By O. Porterfield, M. O’Kane, M. Endersby

BHP Iron Ore initiated research programs in January 1995 to develop long-term plans for decommissioning waste rock material at its Mt. Whaleback operation. More than 2 Gt (2.2 billion st) of waste rock were deposited during the past 30 years. Ultimately, a total of 4 Gt (4.4 billion st) will be deposited in waste rock dumps constructed near the open pit. The Mt. Whaleback operation is located in a semiarid climate adjacent to Newman, Western Australia. The primary research program includes the development of technology for the long-term performance of the waste rock dumps with respect to vegetation, slope stability, surface runoff, erosion and water infiltration. This paper focuses on the design and implementation of a cover system to prevent water infiltration to the underlying waste rock. Data obtained from a laboratory program and from soil-atmosphere modeling was used to design horizontal field test plots. The construction of the horizontal surface field test plots is discussed together with the field instruments installed to monitor performance. The cover system is designed to maximize infiltration during wet periods for subsequent evapotranspiration while minimizing surface runoff. The result is a near-zero net infiltration to the underlying waste material. An important feature of the design is the use of run-of-mine waste material as the cover material. Monitoring is in progress and will continue for at least two annual wet/dry cycles. The optimum cover system should minimize the net infiltration of water to the underlying waste rock while maintaining physical and ecological integrity for long-term performance.

Jan 1, 2000

By Robert D. Brown

The purpose of this paper is to tell a story - and it is a story with a moral. My topic is Present Trends in the Tax Environment Affecting Mineral Development in Canada, and the first thing to recognize is that, with depressed metal prices and weakening western economies, taxes, in and of themselves, are not really the cause of the Canadian mining industry's present doldrums. But the character and level of mining taxes in Canada has had a profound influence on the development of the industry over the past decade, and the expectations of what taxes the industry will face in future years will influence the industry's further growth. My theme today is that, in Canada, our tax system has, in the past, served as a negative and destabilizing influence in the mining industry: it has contributed to a major short-fall in investment commitments and hence in the contribution which the mining industry can make to the Canadian economy, and the adverse effect on the industry of previous high tax rates was made far worse by the confusing, contradictory and perverse nature of the tax system itself. This is a story with some happy parts in it, and, in fact, governments in Canada did learn, haltingly and grudgingly, that there are limits on the amounts that governments could safely extract from the industry, and that some assurances of long term fiscal stability were necessary if investors were to be induced to make massive commitments which could only be recovered over very lengthy periods.

Jan 1, 1982

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 Paul F. Ziemkiewicz, Aaron Noble, Christopher R. Vass

Many modern industries rely on rare earth elements (REEs) to produce products that are essential to both civil and defense applications. In a prior study (Vass et al., 2019), we showed that REE grades in acid mine drainage (AMD) and associated byproduct precipitates from AMD treatment (AMDp) warrant evaluation as a feedstock for REE production. The current work extends that effort through a broad survey of 141 AMD treatment sites in Northern and Central Appalachia. In this study, 185 raw AMD and 623 AMDp field samples were obtained and analyzed to assess the REE and major metal concentrations. Results show that an average of 282 μg/L and 724 g/t of REEs occur in AMD and AMDp, respectively. Additionally, both basins contained similar distributions of REEs, and these distributions tended to favor heavy and critical REEs when compared with traditional REE ore deposits.