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By Leslie M. Burnside, Gene E. McClelland, Roy R. Cellan

Revegetation of neutralized heap leach material in the arid environment of the Great Basin represents a challenge of avail­able technology. The chemical and physical environment of spent and neutralized ore is inhospitable for germination and establishment of desirable long term vegetation. Common soil amendments were tested to dete1mine if the heap material could be made more conducive to plant growth. Decommissioned heap material profile samples were collected and reconstructed in columns at bench scale. The column profiles were amended and subjected to three leaching regimes, and representative meteoric conditions. The soil amendments provided positive results for ameliorating the heap material limitations and providing a medi­um conducive to plant growth. The bench scale study also pro­vided insight for the future of heap leach planning and design with successful reclamation in mind at the forefront.

Jan 1, 1998

By Deepak Malhotra

The economic viability of mineral companies not only depends on maximizing mineral recoveries but also on their ability to do so at minimum cost. Increasing pressure to cut costs has resulted In reduced staff, thereby decreasing the capabilities of routine metallurgical audits. This paper reviews a systematic approach to plant auditing which has been used successfully at several operations. Several case studies illustrating the potential benefits that can be attained from flowsheet auditing of mineral processing plants are discussed.

Jan 1, 1991

By M. Nichols

Where am I? Where are they? Where is it? These are the fundamental questions that need to be answered in managing people and resources. This paper explains how GPS positioning technologies answer those fundamental questions and provide better information management from initial exploration work through daily mine operations to reclamation work and environmental monitoring.

Jan 1, 1998

When longwall equipment is being specified, a nominal capacity is generally given on which to base the design of the various face and out-bye systems and components. This capacity generally comes from a nominal annual capacity requirement based on realistic utilization rates. From illustrative examples of simple system simulation, this paper sets out to show that a single nominal capacity is not sufficient to size the different systems. The manner in which the Longwall is operated and the overall system configuration and availability can have a significant impact on overall productivity.

Jan 1, 2008

By R. M. Guymon, D. D. Lauriski

Safety management can best be described as how each company deals with the control of hazards (human or mechanical) to reduce costly accidents and employee injury caused by accidents. Properly used, effective safety management can mean the difference between being a highly productive, cost-efficient operation or one that "walks the fence," that is less productive with higher product costs. At Utah Power & Light Co's mining division, effective safety management has been used as tool to achieve this difference and remains as the number one priority to maintaining that difference.

Jan 1, 1990

By R. W. Smith, D. L. Taylor, K. A. Altman

The importance of metallurgical information in reaching appropriate decisions during the development of mining projects is demonstrated. A financial analysis is calculated using discrete system simulation. The results are compared to the results of a traditional sensitivity analysis. The traditional analysis is shown to have the potential to overestimate the value of mining projects. The type of statistical distribution used in a random number generator affects the results significantly. The statistical method of analysis provides insight into the amount of metallurgical testing needed and provides verification of how representative the samples are.

Jan 1, 2002

By Kenneth Savidge

With the recent demand for increased coal production there has been a corresponding increase in the horsepower of the shearing machines. The resultant increase in the machine haulage pull has heightened the incident of haulage chain breakage resulting in machine downtime, but more seriously the danger to face personnel. This paper discusses the application of chainless haulage to longwall mining and describes the systems currently available.

Jan 1, 1978

By J. J. Bean

The development drilling program of the Copper Cities mine indicated that the molybdenum content of the ore would be about 0.011% MoS2' The molybdenum content of the Miami mine at the same time was about 0.025% MOS2' The Miami mill had a very successful molybdenum operation which used bleeder turbine steam from the Miami power plant for the steaming operation. The much lower grade of the Copper Cities ore, the absence of a source of low cost steam and the use of sodium aerofloat as the copper collector which Miami experience indicated did not respono readily to the steaming technique made very doubtful the success of a similar operation at Copper Cities. However, the relatively few pounds of copper that could be recovered from the low grade Copper Cities heads made very desirable the recovery of the molybdenwa,as a source of additional revenue. Accordingly, shortly after the Copper Cities mill began operation, a research program was instituted to develop a suitable method of molybdenum recovery. This program explored first, the successful steaming process then in use at Miami and as expected, found it unable to decompose the sodium aerofloat copper collector. The known chemical depressants were then tried without much encouragement. Finally the copper concentrate was dried, not roasted, to 2-3% mOisture and this along with sodium ferro-cyanide and cyanide resulted in sufficient copper depression that a final molybdenum concentrate containing 1.0% CU could be made. The bench scale testing was followed by pilot plant testing. Sixteen

Jan 1, 1972

By J. P. Sieverson

The Comprehensive Environmental Response, compensation, and Liability Act (CERCLA -commonly referred to as Superfund) was passed into law in December 1980 in the wake of such incidents as Love Canal and the Valley of the Drums. Superfund was originally perceived as a way of cleaning up spills of hazardous substances and/or cleaning up abandoned hazardous waste dumpsites. In February 1981, Michael Cook, EPA deputy assistant administrator for hazardous emergency response, called Superfund "a tremendously powerful law. It could revolutionize the way the environment is protected, but we certainly don't intend to realize the full potential of the law for some time." These words have proven prophetic for Asarco's East Helena Smelter.

Jan 1, 1988

By Jack S. Watson, Rasika Nimkar, Robert M. Counce, BRADLEY BENNETT, Patrick Zhang

The purpose of this work is to develop a conceptual recovery process for thorium dioxide (ThO2) from its primary source, monazite. The study-level design presented in this paper represents an economically viable method for conducting ThO2 extraction from monazite ore while also recovering byproducts that include P2O5 and other rare earth element oxides rather than producing unnecessary waste streams. Three key points to note in the development of this process design are: (1) the process economics relied heavily on recovery of rare earth byproducts, (2) the thorium handling portions of the process could effectively be segregated from the rare earth and phosphate handling portions of the process, and (3) the thorium and uranium content in waste streams should be carefully managed and eliminated where possible.

By L. Hales

Neural networks are a generalized, multivariable non-linear modeling technique that can be used to model mineral processing operations. Neural networks will be described as will their use in modeling column flotation. Optimization of column flotation will be explored and discussed by using the neural network column models.

Jan 1, 1996

By Betty L. Gibbs

Mine planning and scheduling done with computer programs is possible only after extensive work has been completed to define the geologic extent of an ore body and an overall mine design. Mine planning methodology on computer can vary from computerized engineering tasks through systems which completely optimize a plan with little input from an engineer during the actual scheduling process. However, a strong emphasis is placed on producing practical mining sequences which may be "best" rather than "optimum". This section offers several viewpoints on the planning process using computers. Interactive planning and scheduling systems are attractive for many companies because they are easy for engineers to understand, and the results are acceptable. The engineer develops an open pit mine sequence by trial and error using interactive graphics. The results of this approach can usually be improved. A computer program can help an engineer make many trials in a short time period and provide a higher level of confidence that a "best" plan has been generated.

Jan 1, 1989

By William J. Bryson

Just picture, if you will, the hot, lonely and desolate Ochre Mountains west of Salt Lake City. There works a grizzled old miner, his boots worn down, his clothes hang on a body stooped by years of hard labor. His skin is wrinkled and leather toughened by many years in the hot desert sun. His ever faithful burro stands patiently in the shade of a large rock as the tired old miner examines ore samples just acquired that very morning. Suddenly the old man's eyes widen, his breathing becomes rapid. 'Leaping to his feet, with a gleam in his eye, he cries, "Eureka, I'm rich, I've found the mother lode. This is where I will start my digging. " Without warning, the silent wilderness is alive with wild, shouting, charging figures! Frightened the old miner glances about him wide-eyed and pan- icky. His heart sinks, dismayed he now knows all is lost, this is the end. For there leaping from behind rocks and brush papers in hand, are the men from the Department of Interior, Bureau of Land Management, State Mine Inspectors, OSHA, MESA, EPA, OEO, and the never ending list of regulatory bodies related to todays mining industry.

Jan 1, 1975

By Paul L. Russell

Numbers, arithmetic, mathematics. Where did it all come from? Who needs it? We all do, but many school children would not agree. Engineers, physicists, accountants, tax collectors, and most of the general public are well aware that modern society in large part is founded on mathematics and could not exist without it. Mathematics developed over thousands of years as part of the everyday life of man. No one area, tribe, or race can claim discovery. In fact, from the records that do exist, it is evident that many facets of mathematics were discovered independently of others who made similar discoveries. While proof may be lacking, the earliest concepts of mathematics may be some 250,000 to 300,000 years old. The first use of numbers as written records is unknown. However, a bone of a young wolf deeply cut with 55 notches-arranged in two rows, one of 25 notches, the other of 30-was found in Czechoslovakia. Dated to be about 30,000 years old, it is perhaps an early record of some kind of counting system. It is assumed that mathematics was developed as an answer to man's practical needs, but anthropological studies suggest that the art of counting may have developed in connection with the needs of primitive religious ceremonial rites. Fingers probably were first used to designate sets of from one to five objects. Using both hands, up to 10 items could be indicated. As civilization developed, so did the need for more flexible systems to record items of trade, measure land, and figure taxes. Aristotle noted that the development of the decimal system comes from the fact that most people are born with 10 fingers and 10 toes. In spite of this obvious fact many early civilizations used binary, ternary, and quinary systems while vigesimal systems (with 20 as a base) and even sexagesimal systems (with 60 as a base) were used by others. A form of writing was in use in both the Mesopotamian and Nile valleys as early as 3000 to 4500 B.C. In Mesopotamia, wedge-shaped marks were impressed upon soft clay tablets that were hardened in ovens or by the sun. Many thousands of such tablets have survived. When the tablets were finally deciphered, some were found to be records of items shipped in trade, inventories, tax accounts, and mathematics exercises for teaching. Mesopotamia is also the source of an interesting board game dating back to about 2500 B.C. Its buttonlike men and triangular dice were apparently used with squares of shell, inlaid with lapis lazuli and red sandstone. Unfortunately, rules of play were not found. In Egypt, record preservation was somewhat better. Discovery of the Rosetta Stone in 1799 eventually led to deciphering the Egyptian hieroglyphics that included a numbering system at least 5,000 years old. These records show a competence in counting and numbering. A calendar of good accuracy may have been in existence as early as 4,200 years ago. Mathematics, as practiced today, developed when the Greeks added logic and proof to arithme-

Jan 12, 1982

By Annan Cook

J.R. Atkinson, office engineer to Kennecott Copper Corp., summarized data on the Mineral Park area [Wallapai (Chloride) Mining District, Mohave County, Arizona, Fig. 1] and submitted it to the New York office in 1950. He recommended an examination. Weston Bourret, a Kennecott geologist, accompanied by B.S. Butler, the well known former US Geological Survey geologist, examined the larger of two hydrothermally altered areas in Mineral Park that same year. Bourret recommended that the property be optioned and mapped. Georges Ordonez, Kennecott's chief geologist, after a field examination, agreed with Bourret's conclusions At the end of the summer of 1951, Annan Cook (another Kennecott geologist) accompanied Ordonez to the property prior to starting a mapping program. At Ithaca Peak, the structure, alteration, and reddish-brown coloring in leached cavities-hematite, jarosite, and goethite with minor copper staining - made an interesting target. The Peak, which has since been mined, was a Laramide quartz monzonite porphyry grading into quartz porphyry, penetrating Precambrian rocks. Turquoise had been mined from several workings on the Peak. Surrounding the central area of alteration, but mainly to the northwest, there were many long-abandoned underground workings mined for zinc, lead, gold, silver, and copper. To the west of Ithaca Peak within the main area of alteration, surface evidence of a chum drill hole suggested interest in the disseminated mineralization probably prior to World War II. A topographic and geologic survey of the altered Ithaca Peak area was initiated by Cook in September 1951. He was assisted by Richard Vosburgh, field engineer, and by four geologists: Charles Goddard, III, Donlon LoBionda, Keith Martin, and A.T. Stone. When Cook returned to New York, Vosburgh was left in charge. Mapping continued and diamond drilling took place during the winter of 1951-1952. Drill sites were selected entirely on the basis of surface geology. Five drill holes, including a flat hole, located around the flanks of Ithaca Peak, averaged about 183 m (600 ft) in length. A sixth hole caved at less than 60 m (200 ft). The best values obtained were in the first hole (-45°): 90 m (300 ft) averaged 0.62% copper and 103 m (337 ft) averaged 0.041% molybdenum. In another hole, 43 m (142 ft) averaged 1.09% copper and 0:023% molybdenum. The values of copper and molybdenum in these two holes were generally higher than in the remaining holes, although molybdenum values were always around 0.024% or better. The New York office decided, however, to abandon the project even though the remaining field crew of three had recommended more drilling.

Jan 1, 1991

By Elza F. Burch

Feeding 600 pm X 0 raw coal to heavy media cyclones, along with the +600 pm size coal, produces an efficient separation of both the +600 pm and 600 pm X 150 pm sizes. Major advantages of the process include the elimination of desliming screens and secondary fines circuitry for cleaning the 600 pm X 150 pm size coal, and result in a very simple circuit. Incorporating four 660 mm diameter heavy media cyclones, the Providence Plant of Island Creek Corporation has operated efficiently for ten years with a magnetite consumption rate of less than 0.45 kg per ton of raw feed at a feed rate of 454 tph.

Jan 1, 1988

By John A. Herbst

At the last Comminution Symposium a challenge (Meloy and Williams, 1992) was issued to "predict the typical straight-line, self similar" tumbling mill product size distributions using a population balance model (PBM). Implicit in this challenge is the assumption that the PBM is inadequate for predicting real world grinding performance. This response is presented in three parts: I. Theoretical analysis of the general PBM and its appropriateness for comminution system modeling. II. Examination of the accuracy of prediction of real world milling behavior using linear and nonlinear PBMs. III. Evidence from recent microscale comminution research. This paper concludes with recommendations concerning future research which will: 1. further elucidate mechanisms of particle destruction and creation as well as attrition and 2. increase the accuracy of model predictions in highly nonlinear situations

Jan 1, 1997

By Darrell M. Hladun, Linda M. Dufour

The benefits of computer simulation in the design of a refracto­ry gold autoclave facility is discussed. Three computer simula­tion programs used for autoclave design are briefly described in this paper. 1) METS IM® - A Process Simulation Software Package Developed by Proware: Mass and energy balances are conducted around the auto­clave and its ancillary processes. Results from the process simulation define process equipment requirements and are used for establishing operating costs. The p_rocess model integrates various unit operations including grinding, acidu­lation, pressure oxidation, counter-current-decantation, neutralization, cyanide leaching, and carbon-in-pulp or car­bon-in-leach. 2) ALGOR® - Finite Element Analysis (FEA): A computer software program is used in the design and analysis of brick lined pressure vessels, such as autoclave, heater, and flash vessels. This software creates a steady state thermal model, and accurately predicts temperature distribution throughout the entire vessel, including nozzles, which represent regions of high thermal intensity. 3) Compress©: A software package developed by Codeware used for the sizing of pressure vessel components, includ­ing shells, heads and nozzles, according to ASME Boiler and Pressure Vessel Code, Section VIII, Division 1.

Jan 1, 1996

By L. K. Holder

"The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), commonly known as Superfund, mandates evaluation of remediation alternative using nine criteria: (1) overall protection of human health and the environment, (2) compliance with ARARs (applicable or relevant and appropriate standards), (3) long-term effectiveness and permanence, (4) reduction of toxicity, mobility or volume, (5) short-term effectiveness, (6) implementability, (7) cost, (8) state acceptance, and (9) community acceptance. Many states have adopted these or similar criteria for remedy selection under state laws. Although not explicitly addressed in the CERCLA criteria, consideration of sustainability can be incorporated into these criteria. This paper explores how sustainability can be evaluated for remedy selection using the CERCLA criteria. INTRODUCTION Sustainability considerations can be incorporated into all phases of site remediation: • Site investigation (remedial investigation). • Remedy selection. • Remedial design. • Remediation construction. • Operations, maintenance, and monitoring. This paper focuses on remedy selection. Many have looked at remedy selection using sustainability criteria. However, CERCLA and corresponding State programs require remedy selection using mandatory criteria. This paper shows how sustainability can be explicitly considered using the mandatory criteria. REVIEW OF CERCLA CRITERIA First, we review the definitions of the CERCLA criteria. We then explore how sustainability criteria can be fit into the CERCLA criteria. Overall Protection of Human Health and the Environment This criterion addresses the degree to which each alternative is protective of human health and the environment, considering both long-term and short-term risks. Overall protectiveness is a ""threshold"" criterion, in that alternatives that do not achieve adequate protection of human health or the environment are eliminated from further consideration. Evaluation of this criterion is derived from the evaluation of the other criteria (e.g., long-term effectiveness and permanence, and short-term effectiveness). It is not an independent criterion, but more a summary of the overall evaluation."

Jan 1, 2015

By Prakash M. . P. E. Donde

1. INTRODUCTION The Washington Metropolitan Area Transit Authority (WMATA) has often taken a leading role in introducing innovative construction technologies to build its transit system. Most recently, Contract Section E-5a, which included Fort Totten Station and Tunnels was constructed utilizing the New Austrian Tunneling Method (NATM) in soft ground. Along with the station and tunnels, two permanent shafts were also constructed in soft ground employing the NATM technique. This project is located within the District of Columbia on the Greenbelt Route. The subject of this paper is to discuss the unique method of construction of these two shafts, and explore the benefits of applying the NATM technique to the construction of deep shafts. The design of the shafts was performed jointly by Jenny Engineering Corporation of Springfield, New Jersey, and Mayreder Consult of Linz, Austria. The designers also provided construction support services and a resident NATM expert at the site during construction. The construction of the project started in April 1988 by a joint venture of Mergentime Corporation and H. T. Construction, a subsidiary of Hochtief Company from Germany. This $48.7 million construction project has been completed. 2. SUBSURFACE CONDITIONS The two NATM shafts are located primarily in Cretaceous-age deposits that are over 100 million years old. These deposits are intermixed and lenticular in nature

Jan 1, 1993