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By C. Copeland, S. Kawatra

Airborne particulates can be generated by combustion processes, comminution, or materials handling, and regulation of these particulates by EPA are becoming progressively more stringent. Regulations will soon include “nanoparticulates,” particles finer than 100 nanometers, which are believed to have significant health effects due to their high surface area and reactivity. Although it was argued that nanoparticulate concerns were only important for combustion, studies here have shown that material handling and comminution release significant quantities of nanoparticles into the air. Laboratory studies have shown that sodium metasilicate reduced airborne particles finer than 10 micrometers (PM10) by 86% and particles finer than 2.5 micrometers (PM2.5) by 80% for iron ore. Additional studies were conducted which revealed that nanoparticulate emissions were present in the types of operations conducted at pyrometallurgical facilities.

Jan 1, 2007

By Charles A. Ramsey, Kathleen S. Smith, Philip L. Hageman

We developed a statistically based strategy for sampling the surficial material of mine-waste dumps for use in screening and prioritizing historic dumps on abandoned mine lands. This sampling strategy entails the collection of a representative composite sample from individual dumps and allows for regional or watershed-based assessments. One 30-inment dump-composite sample collected using this sampling strategy contains as much information, relative to average value, as 30 individual grab samples at 1/30 of the analytical cost.

Jan 1, 2000

By K. Terhaar, K. Prisbrey

The objective was to determine operating protocols for a lead and silver column flotation cleaner being considered for installation at Sunshine Precious Metals Inc. 's Kellogg mill in Northern Idaho. In this column, tetrahedrite and galena were floated, and pyrite and other gangue minerals, including siderite and silica, were depressed. The procedure was to develop a dynamic simulation using a linear transfer function approach. The transfer function related cause-and-effect variables such as the influence of collector and depressant dosages on recovery and grades. Bench-scale flotation tests followed by pilot column testing provided the data used to develop a linear transfer function. The transfer function was derived using a spreadsheet. This model was applied to simulate how the flotation column could be made to respond to disturbances in feed grade. The results were that xanthate, zinc sulfate and sodium cyanide were found to be suitable controls for grade and recovery. Simulations showed the best sequence of manipulations of these reagents, and these sequences are useful for future operator training. The conclusion was that linear transfer functions were able to simulate lead and silver recovery, develop scenarios for operator training and provide a foundation for future on-line control.

Jan 1, 2002

By K. Vanbroekhoven

An industrial site near the centre of a historical town in Flanders is characterized by chromium(VI) contamination of the groundwater. Since the potential for natural attenuation was not sufficient to control the groundwater plume as observed from different analyses like pH, Eh, soil oxidation and reduction capacity, the feasibility of site remediation based on in-situ bioprecipitation of chromium was examined in lab microcosm studies. By creating reducing conditions by addition of a carbon source in the groundwater, chromium(VI) can be biologically reduced to chromium(III), which can form an insoluble precipitate of chromium(III) hydroxide. Microcosms contained contaminated groundwater and aquifer samples that were collected and manipulated under anaerobic conditions. Three different carbon sources were screened for their effectiveness: molasses from sugar beet production, molasses form starch production (protamylasses) based on potato juice and lactate. The different concentrations of sugar molasses were used to determine the optimal conditions. A range of parameters was monitored at regular time intervals for a period of six months such as chromium(VI) and chromium(III), DOC, methane, pH, Eh. A rapid conversion of chromium(VI) to chromium(III) was observed for all conditions tested. However, extensive removal of chromium from the groundwater by precipitation was only achieved for a limited number of conditions. In general, lactate was found to be the most effective carbon source, slightly better than the lowest concentration of sugar molasses that was tested, which itself was more effective than molasses based on potato. Higher concentrations of molasses, although causing a steeper decline in redox potential, resulted in less effective Cr removal. Typically, the fermentation of molasses results in acidification and this drop in pH may hinder the formation of insoluble chromium(III)hydroxides. It may also be possible that certain components of the molasses form soluble complexes with chromium(III). For lactate, no significant drop in pH was observed. Following the laboratory microcosm tests, the stability of the chromium precipitates was examined by performing a sequential extraction on the microcosm materials. These were performed under redox conditions which were similar to the ones observed in the field. Since the outcome of these tests was positive, a pilot scale test was implemented in the field in April 2005. Two different substrates, the cheap waste product sugar molasses and lactate are being injected creating two different impact zones and typical parameters are monitored. Frequent re-injections were important to maintain reduced conditions and are carried out three-weekly up to now. To study the stability of precipitates formed, mesocosm socks containing aquifer material were installed in the monitoring wells and harvested at regular intervals. Results of this pilot test will be presented and compared to the laboratory results. Based on the success of this field test, a full scale process will be designed and implemented as remediation strategy.

Jan 1, 2006

By L. M. Klimov

In recent gears in the coal industry a great deal of attention is attached to the questions of elaborating and introducing the problems of planning and management and, first of all, in the sphere of mine production. The basis for planning of mi- ne production is complexes (sets) of problems for planning the development of mining operations based on different time periods, ensuring the follow-up of changes of mine productive capacities. Complexes of problems for planning, the development of mining operations at existing underground and surface mines within the OASUugol system (Coal Industry-wide Automatic System of Management) are aimed at ma- king decisions close to optimum, i.e. general lay-out of panels, blocks and pillars; transport and ventilation networks; schedules for working out parts of mine take; coordinated mining operations with limited labour and material resources; control of mining operations and ultimately maintaining productive capacities of existing mines at the required level.

Jan 1, 1979

By Alan R. Grant

Interpretation of presently available geological information indicates that most of the periods of significant metal deposition in the Washington Cascades Range are, at least in part, genetically related to late Cretaceous -Tertiary intrusive episodes. Chemically, the most favorable environment for base metal deposition is high in potassium. Characterizing the advanced stages of these chemical alteration conditions are the silicate mineral assemblages orthoclase and/or secondary biotite. Wall rock alteration includes both deuteric and hydrothermal processes, the intensity of which primarily depends upon the degree of fracturing in the country rock prior to the introduction of secondary material. Broadly speaking, the primary physical controls for the distribution and concentration of sulfides appear to be a series of structural couples involving both northwest (paralleling regional trends) and northeast--striking systems. Meaningful base metal exploration in the Washington Cascades demands a basic understanding of the various geologic factors related to the distribution of the sulfide deposits. Any geologist contemplating Cascade work should be well grounded in the fundamental concepts of petrology and structure.as these constitute two of his most beneficial aids. The acquisition of the detailed data necessary for this understanding may seem a bit academic, yet it has been demonstrated in numerous instances that a fair economic appraisal of a particular property or mining district depends primarily upon the ability of the geologist to recognize the subtle environmental differences which could lead to the discovery of a major ore deposit.

Jan 1, 1971

By E. K. C. Chanda

The best use of available reserves to give good metal recoveries relies on short term mine production scheduling.-The aim is usually to produce a plan to guide mining in specific areas that will enable mine operations to deliver the budgeted tonnes and grade to the mill and keep within the long range mine plan. Thus, short term production scheduling is an important aspect of the open pit mine planning function. Since the 60's increased attention has been paid to effective production scheduling as a means of improving the economic viability of existing mines. Hence, mine scheduling scheduling systems have been evolving rapidly during the last two decades. These systems include manual techniques, computer based simulation, mathematical programming and more recently Computer Aided Design (CAD). Some general drawbacks of the current scheduling systems are that firstly, the costs of acquiring and using them are not at all insignificant especially for small to medium sized pits. Secondly, there is an inherent trial-and-error aspect in these systems. Thirdly, they tend to be suited for specific orebody geometries, hence lacking the necessary generality. For instance, the use of computer programs for planning open pits to mine stratiform orebodies raises problems which are not usually met when massive orebodies are considered. There for, a need exists to develop simpler but effective short term pit scheduling procedures suitable for stratiform type orebodies, considering their geometry and geology. This paper describes a PC- based model designed to assist the planning engineer in optimizing the short term production schedule in open pit mines with stratiform orebodies. The model is based on a combination of linear goal programming and deterministic mining simulation. The orebody model is made up of ore and waste mining regions where winning and and/or stripping are taking place. These shovel regions form the basic planning elements in the model. This approach does not require the laborious preparation and use of a regular block model. The computer program consists of main modules: (i) Data capture - processes the raw data into the required format for mine planning. (ii) Precedence mining constraints - checks the status of each shovel .region at the beginning of a given scheduling period with regard to geometrical mining constraints such as undercutting. (ii) LP- Optimization - provides an optimal selection of ore shovel regions which do not violet geometrical constraints for mining in the period, the objective, being to maximize the contained metal equivalent in the blended R-O-M ore and at the same time to minimize deviations in grade and tonnage from the call values. (iv) Post LP-Simulation - enables the user to smooth out the LP solution in order to adjust it to a practically executable plan and simulates mining of ore and waste for the period. Shovel allocation to selected ore and waste shovel regions, unit operations and depletion of reserves are executed in this module. Preliminary testing of the model for monthly production scheduling using data from Nchanga OPen Pit on the Zambian Copperbelt indicates that it can be a useful planning tool and gives acceptable results.

Jan 1, 1992

By M. Karmis

The Virginia Center for Coal and Energy Research is leading an interdisciplinary coalition to identify potential carbon sequestration sinks in unmineable coalseams as part of the U.S. Southeast Regional Carbon Sequestration Partnership. The Virginia Center for Coal and Energy Research and the Eastern Coal Council are leading education efforts for the project, as well as specific outreach efforts in Central Appalachia in order to develop a process for stakeholder education and engagement in sustainable energy.

Jan 1, 2007

By Yoshiak Mizuta, Hi Keu Lee

The manuscript of this paper was not available for publication when the Proceedings went to press. Should the authors elect, they may distribute copies at the time of the Symposium

Jan 1, 1986

By William M. PhD. Schafer

The net acid generation (NAG) pH method is an important analytical tool that supplements static and kinetic tests for assessment of the acid generation risk of rock samples. This method is useful because it is simple, rapid and cost-effective; it combines features of the static and kinetic tests; and it can be conducted at mine assay labs. The NAG pH test is particularly effective for operational testing programs used to classify, selectively handle, and route potentially acid-generating waste rock. The NAG pH procedure is based on a 24 hour oxidation of a pulverized rock sample with hydrogen peroxide and subsequent measurement of the sample's pH. If the NAG pH is below a critical value, determined empirically, then the sample has the potential to generate acid in the field. The critical NAG pH value is typically within the range of 3 to 4.5, but the exact relationship between NAG pH and potential acid generation should be determined individually for each mine site, based on comparison with results of acid base accounting, humidity cell tests, and mineralogical analyses. Calibration and use of the NAG test for predicting ARD risk at several mines are described in this paper.

Jan 1, 2000

By Ing. Ludwig Schlebusch

The significant growth of the world population and its demand for an increasing standard of living leaves no other choice than continuously augmenting industrial production and making available steadily greater quantities of raw materials at still better qualities. Therefore, any raw material has to be utilized to the greatest possible extent and processed at optimum economy on large mechanical equipment. The layout of processing facilities of large throughput rates can be based on multiple or single lines. The latter enables the application of large machines of optimum size. Proven equipment for homogenizing, classifying, separating superfine material, sorting and dewatering are-now available in optimum sizes. By the use of these large machines operating cost of pit coal preparation plant can be significantly lowered by reducing the specific requirements regarding space, capital investment, energy, operation and maintenance.

Jan 1, 1980

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 Pieter C. van Aswegen, J. A. Brierley, C. L. Brierley

The bacterial-oxidation (BIOX®) process for the pre-treatment of refractory ores for gold recovery is marketed by BlOMlN Technologies S.A. The process was originally developed by GENMIN who is still providing testwork, design and commissioning assistance to BIOMIN. Since 1986 three BIOX® plants have been commissioned by GENMIN. A further two plants will be commissioned during 1993 and 1994. The commissioning and operational experiences from these plants are described in the paper.

Jan 1, 1993

By J. F. T. Agapito, C. E. Brechtel, M. E. Adam

Full-scale stopping and simulated over- cast structures were constructed in large opening (30 ft high by 55 ft wide) room and pillar excavations in an oil shale mine. The program was undertaken to develop construction techniques and to generate data on structure costs and leakage rates. Leakage rates were measured using both sulfur hexafluoride tracer gas and "brattice window" methods at varying differential pressures. The measurements were conducted before and after a full-scale face blast to characterize the effects of blasting on leakage, and blast air pressures were measured across the stoppings. The operating performance of different combinations of permanent and temporary stoppings was evaluated by developing an operating model for a two-panel oil shale mine. The operating performance for the different stopping combinations was then compared to the system cost to evaluate the overall performance.

Jan 1, 1987

By A. Shtiza

This literature review discusses the role of the Albanian institutions, the natural resources industry, potential investors and stakeholders in order to provide a set of indicators that can help to monitor amelioration within sustainable development principles. A map with the potential prospects of the natural resources will be a first step in identifying the further potential for exploitation. Mineral resource policies and governance, sustainable processing and supply chain as well as environmental management information system are some of the crucial tools identified, that will help to set up the indicators and quantify the achievements in environmental management in Albania. Moreover, the integration of practices that will support institutional capacity building; follow-up practices; the mainstreaming of global environment into planning; and the compliance monitoring process will additionally improve the environmental situation in Albania. Aligning business strategy with environmental policy, socio-economic analysis, environmental auditing are decisive tools in order to provide the Albanian authorities with a clear overview of the economic costs and the social benefits for sustainable development.

Jan 1, 2011

By H. Singh

Principal source of rhenium is molybdenite. Depending on the mineral processing route, rhenium can be recovered by one of the several alternative solvent extraction processes. Extensive experimental work has been carried out on the development of tertiary amine extraction process for treating very dilute highly impure scrub solutions obtained during scrubbing flue-gases of molybdenite oxidative roasting. Equilibrium data has been obtained under various process conditions by tracer analysis using radioactive Re-186. Extraction with 1% solution of a high molecular weight tertiary amine in kerosene, followed by scrubbing of organic extract with a solution of sulphuric acid and stripping with ammoniacal ammonium sulphate yields high recovery, concentration, and purification.

Jan 1, 1982

By Larry DeGraff

With the increase of new mine development in the past several years, many coal mines have decided to self- perform the design and construction for their slope development projects. The development process of determining the proper configuration is challenging, and a major economical consideration. Greenbrier Smokeless Minerals engineering staff and consultants, along with DSI/American Commercial, developed a support configuration that was best suited for their slope. The developmental process took into consideration the length of slope, depth of slope at the high-wall transition, economics of a single or multiple entries, waterproofing, stresses on the steel supports and lagging during the backfilling operation. This paper describes the developmental concept of using a single entry, side by side configuration, using steel ?Banjo String? supports with steel plank lagging, to develop a long term permanent installation in a cut and cover application.

Jan 1, 2009

By J. Simmons, P. Ziemkiewicz

Acid-Base Accounting (ABA) is an analytical procedure that provides values to help assess the acid-producing and acid-neutralizing potential of overburden rocks prior to coal mining and other large-scale excavations. This procedure was developed by West Virginia University scientists during the 1960s. After the passage of laws requiring an assessment of surface mining on water quality, ABA became a preferred method to predict post-mining water quality,and permitting decisions for surface mines are largely based on thevalues determined by ABA. In order to predict the post-mining water quality, the amount of acid-producing rock is compared to the amount of acid-neutralizing rock, and a prediction of the water quality at the site (whether acid or alkaline) is obtained. We gathered geologic and geographic data for 56 mined sites in West Virginia, which allowed us to estimate total overburden amounts, and values for maximum potential acidity (MPA), neutralization potential (NP), net neutralization potential (NNP), and NP/MPA ratios for each site based on ABA. These values were correlated to post-mining water quality from springs or seeps on the mined property. Overburden mass was determined by three methods, with the method used by Pennsylvania researchers showing the most accurate results to actual overburden mass. A poor relationship existed between MPA and post-mining water quality, NP was intermediate, and NNP and the NP/MPA ratio showed the best prediction accuracy. In this study, NNP and the NP/MPA ratio gave identical water quality prediction results. Therefore using NP/MPA ratios, values were separated into categories: <1 should produce acid drainage, between 1 and 2 can produce either acid or alkaline water conditions, and >2 should produce alkaline water. On our 56 surface mined sites, NP/MPA ratios varied from 0.1 to 31, and six sites (11%) did not fit the expected pattern using this category approach. Two of eight sites with ratios <1 did not produce acid drainage as predicted (the drainage was neutral), and four of 40 sites with a ratio >2 produced acid drainage when they should not have. These latter four sites were either mined very slowly, had non-representative ABA data, received water from an adjacent underground mine, or had a surface mining practice that degraded the water. In general, an NP/MPA ratio of <1 produced acid or neutral drainage sites, between 1 and 2 produced mostly alkaline drainage sites, while NP/MPA ratios of >2 produced alkaline drainage with a few exceptions. ABA is a good tool to assess overburden quality before surface mining and to predict post-mining drainage quality after mining. The interpretation from ABA values was correct in 50 out of 52 cases (96%), excluding the four anomalous sites, which had acid water for reasons other than overburden quality.

Jan 1, 2003

By Douglas J. Uhren, Gary W. Gilbert

This paper describes the risk elements associated with difficult glacial geology, including boulders, heavy groundwater inflow, and potential running soils all coupled with a potentially corrosive service environment. The matrix workshop for the 168-inchfinished diameter sanitary sewer interceptor tunnel in Columbus, Ohio is assembled with the Design Team and the Owner’s design, operations, and fiscal staff. Corrosion protection alternatives are compared against cost and non-cost parameters with relative risk and weighting factors assigned. The Owner working in cooperation with the Design Team uses the matrix workshop to se

Jan 1, 2001

By Franklin H. Sharp, R. Woods

The operation of the Magmont Concentrator located on the New Lead Belt of Southeast Missouri is described. Ore characteristics affecting lead-copper-zinc separation are enumerated, and the cur- rent methods of separation are detailed.

Jan 1, 1976