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By L. J. Nicks

The current U.S. Bureau of Mines research program is addressing the recovery of flake graphite from kish, a steelmaking waste product, and the use of zeolites from abundant domestic natural deposits for efficiently cleaning up mining industry wastewater. The United States is almost totally dependent on imports for its graphite needs, but this may change depending upon the results from a pilot plant being constructed by industry using Bureau technology. Standard mineral processing techniques were applied by the Bureau to recover high-quality flake graphite from kish. It was considered innovative enough to receive an R&D 100 Award in 1992, and its commercialization has the potential to supply the total U.S. demands for graphite many times over. Zeolites have ion exchange properties similar to ion exchange resins, but are less expensive and available in large quantities. Samples of naturally occurring zeolites were tested for their efficiency in removing metal ions from synthetic and industrial waste solutions. The tests focused on defining their selecting, loading, eluting, and regenerating characteristics, and on developing a method for recovering the metal ions as added value products. The results showed that the removal of metal ions with zeolites from acid rock drainage (ARD) solutions is technically feasible and that this technique has the potential for being used in an integrated chemical treatment systems approach either as a primary or secondary cleaning step.

Jan 1, 1995

By D. W. Fohlen, B. A. Filas

The International Finance Corporation (IFC), the private investment arm of the World Bank Group (WBG), requires all IFC-financed projects to comply with its environmental and social policies and guidelines. IFC's review process involves an environmental and social assessment and the implementation of an Environmental Action Plan (EAP) that will set forth the necessary actions to bring the operation into compliance. This paper provides an overview of the environmental and social policies and guidelines that apply to mining projects and examines how WBG/IFC policies and guidelines are applied to mining projects in developing countries. In addition, it includes a review of the increased emphasis IFC is giving to social issues over the past several years based on the existing WBG policies. IFC’s process for the environmental and social review of proposed investments is briefly discussed. The paper focuses on how IFC emphasis has shifted from the traditional environmental and impact mitigation analyses of a few years ago to the integrated social and environmental awareness, action (EAP), and implementation programs (social plans) required today. Today, IFC's focus is to promote sustainable development by investing in projects that directly benefit local communities and the environment. Examples of these changes will be highlighted by a review of recent investments located in West Africa. The goalposts have not moved, but the rules of the game have become tougher.

Jan 1, 2001

By Rex C. Bryan

An accurate and dependable ore reserve estimate is important to any mining company. It is also essential for development drilling and production planning to know about the distribution of the ore within the area to be mined. This paper will show that in the case of more variable deposits such as uranium, the use of geostatistics is superior to conventional techniques. Unlike conventional methods, geostatistics includes the importance of spatial orientation of measured variables. With the use of variograms in conjunction with kriging, a point or a block may be estimated along with its error of estimation. The existence of disequilibrium can create a severe problem in uranium 'ore reserve estimation, and mine and production planning. Disequilibrium can be simply defined as the ratio of chemical or assay values to gamma equivalent values calculated from the downhole geophysical gamma-ray logs. Various methods for adjusting for disequilibrium have been proposed. Most, however, have side stepped the consideration of disequilibrium itself being a regionalized phenomena; or its, relation to surrounding geology. This paper presents methods of incorporating both aspects. The East Dilts Pit at the Bear Creek Uranium Mine in Wyoming, has been used as a case study. Polygonal, triangular, and lognormal kriging and various disequilibrium adjusted methods, including multi-factor cokriging have been com- pared with the mining experience.

Jan 1, 1982

By Archie W. Fletcher, R. J. Wesely, Nathaniel Arbiter, A. D. Zunkel

In contrast to pyrometallurgy's six thousand year history in the production of metals, that of hydrometallurgy is of relatively recent origin. The earliest reference to it at all was in the 16th century, with the first applications to copper in the 17th and 18th. In the 19th century, increased demands for pure metal resulted in development of electrolytic refining, and early in this century electrowinning. The rapid growth in wpper production in the present century, paricularly in the United States and Chile, stimulated the development of new technology for leaching, and for the recovery of copper from leach solutions. Solvent extraction has become a major factor during the past quarter century by permitting novel leaching technology which produces dilute or complex solutions. In addition, solvents other than sulphuric acid, and chemical methods for precipitating copper metal are now of increasing interest. These are trends which should grow in importance in the future with the need to process lower grade and more complex materials. The evolution of copper hydrometallurgy is reviewed briefly and key factors in recent major developments are presented with details of specific operations and with trends for the future indicated. The relative importance of copper hydrometallurgy is compared to that of pyrometallurgy in the light of probable changes in ore supplies and character.

Jan 1, 1993

By Klaus Böde

Within the national and international strategy of the German based construction company HOCHTIEF, the majority of its business units is equipped with the comprehensive software package ARISTOTELES. This software is a powerful business information system for all accounting and controlling related processes in medium-sized and large construction and other related companies. Due to the complexity of the software, time constraints, and limited financial resources an implementation of this software package requires thorough project management. In this paper the relevant elements of project management are outlined based on practical experiences gained during this international IT - implementation project. Special emphasis is directed to the identification and management of potential risks. In this case particular acknowledgement was given to the multinational nature of the project and modernization of the business. This includes thorough reorganization of the company, significant changes of job requirements, and substantial trainings for its employees. At the same time key success factors like knowledge transfer, adoption of Czech legal requirements, commitment of management, networked thinking, and integrated project planning come into play. The costs for implementation had to be carefully evaluated because the software was implemented in a country with a considerably low cost I price level. All these impacts to the business had to be managed within the scope of transformation of business and political environment from socialist to market driven economy.

Jan 1, 2002

By Harold A. Taylor

The first use of graphite is lost in the mists of time. It was used by primitive man to make drawings on the walls of caves and by the Egyptians to decorate pottery. As early as 1400 AD graphite crucibles were being made in the Haffnerzell District of Bavaria. Through the Middle Ages graphite was confused with other minerals, especially galena and molybdenite. Two common names that are still being used for the mineral are plumbago, meaning lead-silver, and black lead. The latter name implied that graphite is either composed of lead or at least contains a large percentage of it. Gessner is credited with having recognized it as a separate mineral in 1565, but its composition was not determined until 1779, when Scheele demonstrated that graphite oxidized to carbon dioxide, thus proving its carbon constitution. In 1789, Werner named it graphite from the Greek word graphein, meaning to write. The United States has long relied on foreign countries for its graphite supplies. This reliance has been due more to the lack of suitable domestic graphites than to any particular preference for buying minerals overseas. Sri Lankan graphites were imported as early as 1820, and Madagascar graphites have been imported since the properties on that island were opened up about a hundred years later. Mexico has long supplied the United States with most of its requirements for amorphous graphite.

Jan 1, 1994

By M. Karmis

According to international projections and future energy scenarios, coal will continue to be a prominent fuel for the next 25 years. In fact, in many regions around the world, coal is expected to dominate the electricity sector until the year 2030. At the same time, with instability and volatility of oil prices, coal is also positioned as an alternative feed stock for conversion into liquid fuels. Energy economists maintain that coal liquefaction is viable at crude oil prices of $35 or more per barrel. Depending on technology and coal composition, 1 ton of coal can produce 1 to 4 barrels of oil. Increased coal production and the expanded utilization of coal also raise environmental concerns regarding greenhouse gases and the problem of handling CO2. Carbon sequestration research, currently conducted in many parts of the world, has demonstrated considerable potential for C-storage in unminable coal seams. Such geologic storage, when possible, can also be integrated into an enhanced coal bed methane recovery process Can coal fuel power plants and industrial facilities, provide diesel and other liquids and, at the same, also be used as a medium for permanently storing CO2? This presentation will provide a global perspective on these questions and stress on the need to reconsider, or even redefine, coal as the fuel for the future.

Jan 1, 2006

By William Hodder, Ehsan Alavi, Muhib Hussain

Disc Cutter Wear is influenced by several geological and technical factors and excessive wear can have a major impact on the excavation efficiency of Tunnel Boring Machines (TBM). Disc cutter replacement events cause a disruption to the construction schedule and costs, and should be minimized throughout the project to the extent possible. A well-executed cutterhead inspection and maintenance plan can help mitigate abrupt cutterhead interventions and reduce its effect on project schedule and cost. This paper examines cutterhead inspection and disc cutter replacement events as well as subsequent wear data recorded in the first 7km of the 10.3 km long, 6.3 m diameter Coxwell Sanitary Bypass Tunnel (CBT) project in Toronto, Ontario. The CBT alignment is mainly through Georgian Bay Formation shale.

Dec 1, 2022

By Roy C. Fedotoff, Jon Hurt, Gregg Sherry, Gilbert Tang

The 1,380 m (4,200 ft) long New Crystal Springs Bypass (Polhemus)Tunnel (NCSBT) will replace the existing Crystal Springs Bypass Pipeline. This tunnel project is part of the SFPUC’s $4.3 billion capital improvement program to repair and seismically upgrade their aging pipelines, tunnels, reservoirs and dams that provide drinking water to more than 2.4 million customers in the San Francisco Bay Area. This paper describes the development of the tunnel alignment and design, and the complex ground conditions of the Franciscan Mélange. Of particular interest is the challenge of tunneling with a possible downhill grade of 3%, a rigorous environmental process and incorporating the lessons learned from 1960s construction of the adjoining Crystal Springs Bypass Tunnel.

Jan 1, 2007

By M. J. Miller, N. Ripepi, M. Karmis, J. M. Conrad

Unmineable coal seams present an opportunity to sequester carbon dioxide emissions from power plants, while enhancing the recovery of coalbed methane. Injected carbon dioxide is adsorbed and stored on the coal surface while releasing methane that can be commercially recovered. Carbon sequestration, therefore, allows the utilization of unexploited mineral resources while reducing “greenhouse” gas emissions. This paper presents the feasibility, efficiency and enhanced recovery potential of coalbed methane production using carbon dioxide sequestration in the Central Appalachian Basin. The focus of research is on geological characterization of unmineable coal seams in Central Appalachia and the corresponding carbon dioxide storage capacity. Virginia Tech and Marshall Miller & Associates, Inc. conducted this research under the Department of Energy’s Southeast Regional Carbon Sequestration Partnership program.

Jan 1, 2006

By M. A. Trevits

The National Institute for Occupational Safety and Health (NIOSH), in partnership with the Mine Safety and Health Administration (MSHA), is conducting research to test, evaluate, improve or modify coal mine fire-fighting strategies and methodologies through large-scale tests. Since wood is the second most abundant fuel available during a coal mine fire, it was decided that series of large-scale wood crib fire tests were needed to measure the products of combustion and to observe the capability of commonly available direct application fire suppression equipment, namely, fire extinguishers, water and gas-enhanced foam. This paper discusses the wood crib fire tests, provides insight into the products of combustion and describes observations made during the application of the fire suppression agents.

Jan 1, 2009

By K. N. Han, N. S. Kim, H. Yoon, J. S. Sohn

The leaching behavior of silver and silver oxides in ammonical solutions has been studied. The current study is concerned with an effective recovery of silver from secondary sources such as spent silver batteries. Silver associated with these batteries appears in various forms including metallic silver, argentous oxide, Ag2O and argentic oxide, AgO. The leaching behavior of metallic silver in ammoniacal solution has been studied using an electrochemical mehtod. Oxidants used in this study include hyperchlorite, hydrogen peroxide, bromine and iodine. Results on cyclic polarization and Tafel plots on the silver anode in ammoniacal solutions are presented and the results are discussed. The dissolution rate of metallic silver in ammoniacal solutions is also compared with those of silver oxides.

Jan 1, 2002

By Fernando Humberto Muge

One of the problems that arises in the early stages of the mine planning before the determination of the mining exploitation method is to predict what will be the recoverable ore reserves in tonnage, grade and metal quantity, if the select ion is based upon block grades. The estimation of these recuperation or recoverable functions can act as an important planning tool in what concerns the appraisal of the consequences of ore-waste discrimination of individual blocks in a selective mining operation. Estimation methods of all these functions are discussed together with cross validation tests using the available information concerning a preliminary drilling campaign accomplished during the exploration stage of an iron orebody located in the North of Portugal (Moncorvo Orebody).

Jan 1, 1982

By J. Um, B. Morin, P. H. S. W. Kulatilake

Development of a three-dimensional mine visualization model for a section of the mine is addressed first. Discontinuity orientation and location information was taken from this visualization model for use in slope stability analyses. Estimated shear strength properties of discontinuities and mechanical properties of intact rock from the rock mass samples obtained from the mine are discussed next. The paper is then focused on the calculated maximum safe slope angles based on the performed kinematic and block theory analyses using the mapped discontinuities at the mine. Finally, the effects of water that exist in the rock mass, tension cracks, slope face inclination, overall wedge height and double benching on factor of safety of wedge stability are illustrated through limit equilibrium slope stability analyses.

Jan 1, 2002

By M. Akser, M. Tomas

Six Sigma is a methodology that uses a structured and disciplined approach to improve process performance (higher throughput, better recovery, lower cost, shorter cycle time, etc.). Specially trained people called “black belts” lead and manage Six Sigma projects. Black belts, with assistance from their team, ensure that projects follow the DMAIC (define, measure, analyze, implement and control) process phases. Timely completion of each project, with measurable deliverables, is key to Six Sigma’s significant financial success. Implementation of Six Sigma has been growing in recent years in a wide range of industries. The heavy mineral industry, like many other industries, could benefit from what Six Sigma has to offer. Specific Six Sigma project examples are included from DuPont’s Heavy Mineral Production Plant in Florida.

Jan 1, 2005

By I. J. Duckworth

During the last twenty years computers have be-come widely used to assist with the simulation and design of large scale, primary ventilation systems. However, to date there are few computer programs available to help with the modeling of auxiliary ventilation in dead-end headings or tunnels. This paper presents the results of the first year of a research and programming study dedicated to the development of a user-friendly duct simulation tool. Included is a literature review that summarises publications on duct leakage and resistance, on previous programs developed for the simulation of airflow in ducts, and case studies on extended ductlines in mines and tunnels. The methodology behind the development of Ductsim, a Windows based simulation program is presented.

Jan 1, 2000

By T. A. Rundle, K. Kim, W. M. McCabe, E. C. Gregory

Overcoring tests were conducted at the Near-Surface Test Facility(NSTF) to assess the suitability of five techniques (U.S. Bureau of Mines borehole deformation gauge (BDG), Commonwealth Scientific and Industrial Research Organization (CSIRO) hollow inclusion stress cell, Luleå triaxial gauge (LuH gauge), and Council for Scientific and Industrial Research (CSIR) doorstopper) for in situ stress determination in a closely jointed basalt. This effort is in support of the Basalt Waste Isolation Project, which is studying the feasibility of locating a nuclear waste repository in the basalts of the Hanford Site in southeastern Washington. This paper presents the results from the overcoring study that formed the basis for selection of two techniques to be used during the further exploration of the basalt formations at depth.

Jan 1, 1983

By Y. Wang, E. Forssberg, A. Johansson, B. Chan

A super-conducting high gradient magnetic separator with matrix vibration in dry separation mode is a powder purification device, which has been used to remove weakly magnetic impure particles from fine calcite powders below 53 µm in this study. A fundamental question concerned is the evolution of the matrix clogging under gas-solids loads. This paper presents the improvement of the separation selectivity using a method of mechanically based vibration on the matrix in the separator. The functions of the matrix vibration are discussed. The results indicated that the mechanically based vibration on the matrix within a high intensity magnetic field while a feed was introduced in an air stream, was found to be effective for the dry purification of fine powder materials.

Jan 1, 2001

By G. J. Koons, J. L. Uhrie

Field density studies carried out at the Phelps Dodge Chino Mine have found that truck-induced compaction is limited to the upper 2.4 meters (8 feet) of an individual lift. Hydraulic properties of material compacted to field densities were determined in a laboratory setting and saturated flow models were then run, simulating the effect of compacted zones within a stockpile. Modeling shows that compaction can effectively prevent solution flow through large portions of the stockpile, implying that great care must be taken to ensure that ripping is carried out to a full depth of at least 2.4 meters (8 feet) across the entire stockpile to achieve uniform solution flow. Uniform solution flow will result in maximum leach recovery.

Jan 1, 2000

By Stephen H. E. Phillips, Michael J. Beus

A pneumatic impact breaker is used to fragment the rock at the shaft bottom, replacing the drill and blast cycle. A backhoe-type mucker removes the broken rock. The operators are in protective cabs below the bottom work deck in the shaft. Preliminary testing has been accomplished at underground and surface test sites in Arizona. Seven, approximately 6.4 m deep by 7.3 m-diameter (21 ft by 24 ft) test holes, (a total of 45 m (148 ft)), were recently excavated in various rock types, including jointed and massive quartz monzonite and rhyolite. An average advance rate of .4 m/hr (1.24 ft/hr) has been achieved. This includes breaking and mucking the rock. Further data is being sought from an in-shaft demonstration.

Jan 1, 1981