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By Ronald D. Hill

Acid mine drainage is the result of the oxidation of pyrite and similar iron sulfide material and the release of iron and sulfuric acid into the environment. In addition to the acid water flowing from underground and surface mines, spoil materials in surface mines are acidic and will not support good vegetative growth; thus erosion is a major problem. Lime and limestone are the major neutralizing agents used to treat these acidic conditions. Lime is the reagent preferred by industry for treating acid discharges, although a few companies use limestone. Agricultural lime- stone is used to "sweeten" acid spoils.

Jan 1, 1974

By Roy Eric Lurie

Computer based signal processing techniques for obtaining empirical dynamic models from measured mill circuit data are discussed. This modelling is the first step towards designing a particle size control strategy. Experimental data from a computerized acquisition sys tern is examined and analysed, and a number of model identification procedures are applied. The resulting models are compared and a suitable model is selected, illustrating the benefits of computer tools for control system design.

Jan 1, 1992

By Louis W. Cope

The Compañía El Zapote Yacimiento Y Minas, S.A. has an ore body containing 650,000 tons of 0.185 oz/t gold ore in Mexico. Metallurgical testwork has been done to determine the response of this ore to several possible processing schemes. The paper describes the rationale for selecting the Silver State Mining Co. methods in Colorado. Plans for developing the mine and building the treatment plant are described in detail in the paper. Estimates of capital and operating costs are included.

Jan 1, 1984

By S. Siddiqua

Diffusion is known to be the main transport mechanism of contaminants in fine-gained soils. To date, it is still common practice to estimate contaminant migration in the Bangkok Clay by means of pure advection models. A series of experiments with various chemical species was performed to determine transport parameters such as the diffusion coefficients and the distribution coefficients. The soil used was saturated undisturbed Soft Bangkok Clay. Column experiments were utilized in a number of laboratory tests involving advective-diffusive migration. Effective diffusion coefficients of different ions were back calculated from the test results. The distribution coefficients were determined from the results of the column tests and batch test. The results indicate that the evaluated parameters are in the range of values obtained from other researchers on similar kinds of soil. Based on this results contaminant migration by diffusion in the Soft Bangkok Clay can now be performed.

Jan 1, 2005

By P. Maraboutis

Extractive industry (mining and quarrying operations), as other industrial activities, is subject to environment protection laws, regulation and standards such as the Environmental Impact Assessment directive, Natura 2000, Habitats & Birds directive, Water Framework directive etc The European Commission (EC) is aim to strengthen the EU environmental legislation to improve the (environmental and human) safety of mining activities. The mineral processing and the management of the mining waste will be covered by the new amendment of the Seveso II Directive, by a Best Available Techniques reference document (BREF) describing the Best Available Techniques of mining waste management and a new directive on the mining waste management. At the same time initiatives as the environmental liability, the energy taxation for environmental reasons and the natural resources management policy, which will have a positive impact on the protection of the environment, will affect the extractive industry operation procedures.

Jan 1, 2002

By Donald C. Trueblood

Since the Surface Mining Control and Reclamation Act (SMCRA) was passed in 1977, coal mine reclamation has been restricted from utilizing bluff-1ike features in permanent reclamation. This restriction is based on those provisions of SMCRA which require the elimination of all highwalls. In 1987, the Wyoming Mi ni ng Association began an effort to acquire the ability for coal mines to utilize bluffs in permanent reclamation for the purpose of enhancing the post-mining land use. The regulatory reform approach being uti1ized includes formation of a work group with members from industry, government, agriculture, and environmental organizations to prepare a proposal. Advantages of this approach are discussed.

Jan 1, 1989

By Sergey N. Zhurin

At Gubkin Mine (Korobkovo Iron Ore Deposit, Russia) tailings are being pumped into two experimental stopes. Slurry has water content that exceeds 80%. In-situ measurements were conducted to determine pore pressure distribution in the backfilling panels. Numerical FEM modeling has been implemented to infer pore pressure distribution within filled cavities. Field observations reveal that pore pressures within neighboring stopes are slightly interrelated, because of drift connecting stopes at its bottom and single drainage system occurrence within filled caverns. Both extensive field data and numerical analysis demonstrate that water pressure on the bulkhead depends predominantly on filtration rate through bulkhead filters.

Jan 1, 2001

By M. García-Vásquez

In Peru, the third destination in worldwide exploration based on expenditure, mining conflicts have spread dramatically over the last decade. Mining companies need to create new initiatives to avoid social conflicts and strengthen the social capital needed to keep mining in a country with proven mineralogical riches. This document provides information about a research project that explored the opinions and experiences of a resource many times overlooked by companies: the human resource. Over 30 surveys were conducted among professionals working at mines in the Peruvian mining industry, in different departments and from different organizational levels. Mining employees acknowledged that they play an important role in the development of company-community relationships and gave their impressions about initiatives implemented by international mining companies in Peru. Mining employees also provided their recommendations to succeed in a location where cultural differences have not been properly considered.

Jan 1, 2011

By William E. Little, William R. Sharp, Edward R. Kennedy

Cost o f mechanical tunneling requires the knowledge of many machine/rock parameters such as rock types, machine power, penetration rate, cutter life, maintenance schedule, etc. Capital investment, labor requirements, and project scheduling will all play an important role in defining the economics of the overall project. Knowledge of the cost sensitivity of different project parameters will improve the overall success of any particular tunneling project if this information is incorporated into an effective management plan. Through the use of an interactive graphic computer program written for a microcomputer, one has the ability to quickly evaluate relative costs for a variety of parameters for either an existing project or for a proposed site.

Jan 1, 1983

By Robert S. Post

A highly respected coal mining company in West Virginia updated their stacker belt by switching to a new magnetic coupling. The savings they achieved are the subject of this paper. A steep incline and heavy belt loads are powered by a dual drive arrangement. The magnetic couplings were custom designed for complete fluid coupling retrofit and easy installation in the field. Maintenance personnel updated the drives in just a few hours. Over the following several weeks, adjustments were made to the couplings for optimum performance. Cost savings are found in reduced down time, no coupling maintenance, and equipment protection.

Jan 1, 2000

By R. L. Grayson, T. L. Dickinson, C. G. Anderson

Sponsored by the EPA, USGS, DOE, and NSF through the Committee on Earth Resources, the National Research Council’s Committee on Material Flows Accounting of Natural Resources, Products, and Residuals, created in August 2002, studied the value that material flows accounting, which can track the flow of a material from the time it is extracted to its ultimate disposal, may provide for making better integrated economic, social, and environmental policy decisions. This could be a crucial technology for the mining industry to incorporate. This paper will recount the statement of tasks, the study process, and the science-based conclusions and recommendations reached.

Jan 1, 2004

By Jerry L. Hodgson

This paper presents an application case history of the planning methods used for developing, costing and scheduling an underground hydro- electric pumped storage facility in weak rock. This method covers the system configuration, excavation methods and costs, initial support systems and final lining systems. This study was performed by the Omaha District, Corps of Engineers for the proposed Gregory County Hydro- electric Pumped Storage Project, and presents a synopsis and the results of the studies performed.

Jan 1, 1986

By G. Q. Huang, Q. X. Yun, Z. Y. Gui

This paper provides a new approach to deal with control of ore-rock excavation by means of the optimal control theory-an important branch in cybernetics. In the optimal control theory, the elementary functions are state-transition function and objective function. According to the characteristics of mining planning and production, a set of formulation are established to cope with ore- rock excavation. The formulations include basic formula, anti-disturbance formula as well as other special formula. The new approach has been successfully used in several mines of China.

Jan 1, 1996

By J. L. Yordan, T. Hilderbrand, R-H Yoon

High brightness clays are produced from Georgia kaolin by flotation. Fatty acids are used commonly as collectors for anatase, which represents the major colored impurity in the crude. This process requires activation of the minerals with divalent cations such as Ca2+, in which case proper control of the activation step is crucial to the success of the flotation process. In the present work, laboratory tests have been conducted using alkyl hydroxamates as the collector for anatase. A major advantage of using hydroxamate is that this new collector requires no activator. The laboratory tests show also that the hydroxamate collectors produce consistently better products with higher yields from a variety of kaolin clays.

Jan 1, 1994

By Jan K. Wolski

This paper presents a simple method for determining air temperature gradients along a tunnel with time-dependent intake air properties. The variable intake air properties may be the flow direction and rate, air temperature and humidity, and the carbon dioxide content. The transient intake air properties are simulated by a series of steady intake air conditions, using a superposition method. The mathematical model was verified by reduced-scale experiments in the Waldo mine. The method may be usefull in conditions where the computation speed is more important than the precision of the results.

Jan 1, 1995

By M. W. Chanda

This paper presents the development of a rock-creep measuring apparatus using air as the initial pressure source. Servo-controlled machines can and have been used for time-dependent property tests. However, the long-term nature of some tests makes essential the complete independence of stress-maintaining equipment from main power sources or continuously running hydraulic pumps. The main objective of this paper is the development of a creep testing machine that is free from interference arising through power supply interruptions or mechanical maintenance normally associated with many compression testing machines. To achieve this, a compressed-air power source was used to drive a compression ram. A few trial results obtained and analyzed using the transient creep law are in reasonable agreement with the general creep law.

Jan 1, 1993

By Q. Xu, P. Somasundaran

Adsorption of nonionic/anionic surfactant mixtures on kaolinite has been studied, with •Sodium dodecylsulfate as the anionic surfactant, and •Octaethyleneglycol mono-n-dodecylether as the nonionic surfactant. Synergistic interaction between these surfactants was found to cause adsorption of the nonionic surfactant with its hydrophilic chains protruding into the bulk, leading to substantial changes in wettability and dispersion characteristics of kaolinite. Similarly, hydrophobicity changes are observed also for silica particles upon adsorption of nonionic ethoxylated alcohols owing to possible changes in the orientation of the adsorbed surfactant molecules at the interface.

Jan 1, 1993

By J. Partyka

Fumes produced during blasting operations in underground mines are defined in this paper by an equivalent contaminant source. The primary goal is to establish a method which would allow all those parameters not measured directly to be determined reliably from field data. The parameters to be identified are the diffusion coefficient , and the position and size of an equivalent source. The diffusion-value is computed from the peak concentrations taken by two monitors located in the drift. The first monitor is placed close to where blasting pollutants join the main stream, while a second monitors is moved downstream a some distance from the first point. The position and size of the dust source and the total amount of dust produced during blasting are determined from the data recorded by only one monitor.

Jan 1, 1991

By Richard E. Gertsch

The recent upswing in mining coincided with increased environmental concern. These trends have significantly increased regulation, but have not always provided sound environmental protection. Throughout, mining has remained passive, reacting to initiatives from outside. The high road to environmental protection must be an active strategy. The mining industry must take the lead and develop an environmental program effective in price and protection. It must involve all levels of mining. The mining industry should be the real environmental activist. We have the most to gain by sound environmental protection and the most to lose if the environment decays.

Jan 1, 1991

By James A. Brierley, Rong Yu Wan

Bacterial pretreatment was evaluated as a process for enhancing gold recovery from a refractory ore from Newmont Cold's Cold Quarry deposit. This ore is refractory due to sulfide locking of the gold and preg-robbing carbon. The microbe Thiobacillus ferrooxidans effectively oxidized the sulfide component of the ore, but the preg-robbing carbon continued to be active. Thiourea was examined as an alternative to cyanide for extraction of the gold from the biooxidized ore. The thiourea, coupled with CIL, was effective for gold extraction resulting in up to 89% gold recovery for the sulfidic-carbonaceous refractory ore. The thiourea gold complex appears not to be bound by the preg- robbing carbon of the ore when in the presence of recovery carbon (CIL)

Jan 1, 1990