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The advantages of quantitative environmental risk assessment techniques over the more commonly used qualitative approach is widely accepted. One important parameter related to the level of risk is the extent and geographic spread of pollutants. Geographic Information Systems (GIS) provide a powerful and highly flexible tool that increases the sophistication of the risk assessment methodology. Through spatial representation, the estimated risk becomes more comprehensive, thus facilitating the decision making process. In addition, valuable qualitative information can be incorporated into the risk assessment procedure with the help of GIS. This paper illustrates a methodology for quantifying risks posed to human health, by exposure to contaminated land, in a manner, which gives a measure of the uncertainty in the assessment and preserves the spatial distribution of the risks. The case study utilised to illustrate the methodology is a large industrial area around a number of decommissioned minerals production and processing sites with known high heavy metal loads at Lavrio, Greece. The spatial distribution of Pb concentration in soils was derived from 425 soil samples collected over a total area of 120 km2. Indicator kriging was used to quantify the spatial distribution of the risk and related uncertainty and the results displayed in map form using GIS.

Jan 1, 2003

By Steve Kral

Borates are minerals that contain boron. Trace amounts exist in rocks, soil, water and people. Boron-containing ores are rare and U.S. Borax, a subsidiary of Rio Tinto Borax, controls one of the world’s two world-class borate deposits. Through its global systems of mines, refineries, ports, sales offices and distribution centers, the company supplies nearly 45 percent of the world’s demand for borates. Borax has been mining borates in California for more than a century. This year the company celebrated 131 years of continuous business in the Golden State and 76 years at its operations in Boron, the site of California’s largest openpit mine. It also has mines and refineries in Argentina, refineries and ship-ping facilities in Europe and technical staff in the United States, North and South America, Europe and Asia Pacific. So, with the 130±years of borate mining and processing experience behind it as well as its global marketing and distribution centers, there is very little that Borax does not know about borates.

Jan 1, 2003

By Robert E. Jones

The barite industry shares with its associates in the minerals industry the impediments of excessive federal and state regulations. We have learned to exist with the Organic Act of 1976, the Mine Safety and Health Act of 1966, and the Multiple Use Act of 1955. I do not mean to imply by the above that all aspects of mining legislation have been detrimental, however, each of you has been subjected to interpretative restrictions by federal or state bureaucrats. As frustrating and costly as this is to the barite industry, it is not the primary problem facing our segment of the industry at the present time. Our major difficulty today deals not with too much government regulation, but with the lack of a cohesive and consistent government energy program. This administration and those that have preceded it have dealt with intermittent energy crises on an emergency basis. If we remove the political rhetoric which has surrounded each of the more recent major crises, we can liken the action of our federal government to that of a rural volunteer fire department which devotes its entire efforts toward extinguishing existing fires rather than the developing of programs designed to prevent future fires. The lack of a comprehensive energy program has created an environment in which long range planning is extremely difficult, if not impossible.

Jan 1, 1983

By Reynold Q. Shotts

Underground mines, penetrating well below the water table, quickly fill with water when abandoned. Ordinarily, these natural cisterns are not thought of as sources of industrial water. Under special circumstance, if chemically treatable, they might become valuable industrial water reservoirs. An example of a group of about 20 mines in a geological and structural setting insuring water entrapment, rapid recharge and a possible minimum of contamination, are the small, compact Belle Ellen and Piper basins in Alabama's small but second most productive coalfield, the Cahaba. The mines have been abandoned from more than 50 to less than three years. The county now produces about a million tons of coal annually, all from strip mining. Figure 1 shows an idealized cross section of the strata in the Belle Ellen syncline near West Blocton, Bibb County, Alabama. Figure 2, 3 and 4 are maps showing the location of the syncline, other structural features, the outcrop lines of the three principal coalbeds underlying the basin, and the mined-out areas on the three beds (1).

Jan 1, 1973

By Allan M. Hale

Taconite tailings reclamation, especially the stabilization of tailings ponds, .dams, and slopes, can be effectively accomplished through the use of appropriate vegetation. Utilizing vegetation provides both aesthetic and ecological enhancement of a site while at the same time protecting tailings structures against wind and water erosion. Generally, the methods and techniques for establishing vegetation are well known; however, there are many site-specific factors that can alter a particular reclamation approach. Those factors include slope gradient, tailings material size, solar exposure, and physical and chemical properties of tailings. In addition to the site-specific factors, variations in climate, geography, and physiography of a region can have a pervasive influence on the success or failure of a revegetation program. Both the site-specific and regional factors control reclamation planning in such areas as plant variety selection, methods and times of plants establishment, maintenance techniques, and subsequent monitoring methods. As a result of this multifactor relationship, it is important to establish a data base that identifies both the site-specific and location conditions in order to tailor the reclamation plan to the specific area. When an appropriate data base has been collected, detailing the various site-specific and regional factors that will influence a revegetation program (in the absence of previous testing), it is very beneficial to apply experimental techniques to develop the reclamation plan for a specific site. The reclamation plan for a specific site may include several techniques adapted for the differences found within the specific site as the result of topographic or other influences. Considering this, the Reserve Mining Company and Dames & Moore undertook to develop a successful reclamation plan based on a detailed test plot program conducted at the Mile Post 7 location.

Jan 1, 1980

By H. M. Breza

Utilization of Bucket Wheel Excavators and Overland Conveyor Systems to remove overburden provides increased productivity and flexibility to a surface mining operation. The utilization of such a system at the Texasgulf Inc. Aurora, North Carolina Mine has significantly improved the overall productivity of the mining operation. System flexibility is evidenced by adaptation to operation requirements such as mining area moves, movement of excavated overburden to designated sites, selective handling of overburden, spoil placement contouring, and providing an environmentally sound and safe operation. System productivity is evidenced by actual case studies relating to overall production, excavation rates, and cost effectiveness.

Jan 1, 1993

By Karen L. Menna

At Digital Equipment Corporation, increasing demands on executive secretaries to share, track, and retrieve information prompted development of ALL-IN-1 System for Executive Services. Executive secretaries asked engineers to combine word processing and electronic mail with utilities for managing time; logging and tracking telephone calls, letters, and inquires; creating presentations; compiling directories; and archiving. The system, two years in development, now automates the president's and senior vice presidents? offices at Digital. It allows secretaries to interrupt any task with two keystrokes, and return later to the original task. The system has speeded customer response, enabled online information sharing, and increased professionalism and customer satisfaction.

Jan 1, 1989

By R. E. Vivas, J. A. Villa

"Located in the state of Colima, Peña Colorada is one of the largest iron ore operations in Mexico. The project is owned in equal parts by ArcelorMittal and Ternium. Though boasting a production capacity of 4.1 Mt/a (4.5 million stpy) of concentrate per year, Peña Colorada is faced with declining ore grades. In order to respond to this situation, Peña Colorada had to expand production even further. This expansion created various challenges that were overcome by the adoption and application of new technology. Examples of these technological innovations are discussed in detail in this article and include improvements in geo-modeling, mine planning, and mine operations. The successful implementation of these technologies paid for itself many times over, and has led to significant improvements in production and performance, while lowering the operating costs and reducing the variance between planning and execution.Project overviewPeña Colorada is a mining company that produces about 30 percent of the iron ore in Mexico. This project generates about 1,200 direct jobs and 3,000 indirect jobs, making a significant contribution to the local economy. Similarly, Peña Colorada invests in its local communities through numerous educational programs, scholarships, university agreements, social development, environmental agreements, etc. Peña Colorada’s operations consist of an open pit mine located in Minatitlán and a pellet plant located in the port city of Manzanillo, as shown in Fig. 1. Technological innovationsMost mining projects around the world typically follow the logic of “mining the next best ore.” Consequently, head grades tend to decline over the life of the mine. In the case of Peña Colorada, a decline in head grade combined with a decline in iron ore prices forced the operation to adapt to a new business environment and adopt new technologies to face these challenges. However, the first step along this process was to increase the confidence and reliability of the resource model. This task involved additional drillhole campaigns coupled with more detailed modeling techniques. Once the block model was completed, new optimization studies and production schedules were evaluated with new optimization tools that improved many aspects of the mine plan. The Peña Colorada block model has undergone 3 expansions to reflect additional information not available in the past. The model has expanded to the East and Southwest. The latest model expansion increased the total number of benches to 98 as a result of positive exploration results. Similarly, new geotechnical studies were prepared, which provided new guidelines for pit slope design, and new technology was implemented to monitor ground movement and slope stability. Two sectional block model views in Hexagon Mining’s MineSight 3D, along with the pit designs and geologic solids are shown in Fig. 2."

Feb 1, 2017

By R. D. Cook, J. L. Johnson

"Measuring mud bed level in a sedimentation device is an important control variable. Methods used to date for this purpose have had limited success providing continuous, consistent measurements at a reasonable price. This paper describes a new instrument for detecting the mud bed / liquor interface as well as bed density profiles. The state of the bed is measured directly with sensors located in the thickener. Data from bench-scale and full-scale tests show that the bed level is well defined and easily detected. In addition, full-scale testing revealed unprecedented information about thickener beds. Variation in bed density gave new insight into thickener bed dynamics, providing design and control opportunities never before possible. This novel instrument can significantly improve thickener control by providing reliable and consistent bed level measurements. It is also capable of measuring bed density profiles that can potentially identify significant operating problems early enough to take corrective action before experiencing costly shut downs. INTRODUCTION Numerous studies and papers have been devoted to the subject of thickener design and operation to achieve specified throughput and discharge densities. Mathematical models have been developed that present methods for sizing thickeners and predicting performance under varying process conditions. The compression effect of deeper beds on dewatering performance is a recognized phenomenon (Wilhelm and Naide 1981). This is one variable of many that are inter-related and influence thickener performance. For example in the steady-state, continuous operation of a thickener, if the solids feed rate increases and the bed level remains the same, the underflow discharge rate must increase with the result of solids concentration being lower. The interactions of these parameters are at the heart of thickener models. One such model (Burger and Narvaez 2007), predicts solids concentration profiles increasing downward and discontinuities between settling zones. This model uses sediment height (bed level) as a parameter that influences capacity calculations to achieve the specified solids concentration of the underflow. Knowing the bed depth is critical to maintaining stable thickener operation. Implicit in these modeling strategies are some basic assumptions such as homogeneous distribution of solids in the different settling zones, plug flow of solids through the settling zones and steady state operation of the thickener. The accuracy of these assumptions has not been verified because there has been little visibility inside the bed of full size operating thickeners. Testing of the instrument presented in this paper demonstrates that it provides a degree of visibility of the dynamics in a thickener not previously possible and indicates that the basic assumptions of the modeling strategies may not be completely accurate."

Jan 1, 2015

By Kevin D. Lofftus

This paper presents a dynamic model for column flotation. The model equations are normalized and the dimensionless groups that are directly responsible in determining the column flotation behavior are identified. The resulting model equations are incorporated for computer simulation. Numerical results from computer simulations are analyzed to gather information about design and operation of column flotation devices.

Jan 1, 1988

By Robert P. Kennedy, Andrew H. Merritt, Edward J. Cording, Thomas R. Kipp

INTRODUCTION Measurement of certain data associated with nuclear testing necessitates the reception of waves at the instrument location which are unaffected by reflection off internal structures or tunnel surfaces. Therefore, in order to provide necessary facilities for the fielding of experiments in support of the underground nuclear testing program, the Defense Nuclear Agency (DNA) commissioned a cost and feasibility evaluation pertaining to the design and construction of large underground cavities in Rainier Mesa. The effort included research into past experience pertaining to the excavation and support of large underground caverns, assessment of the geological conditions which exist in Rainier Mesa, preliminary design of the chambers and their rock support systems based upon the geological setting, development of mining plans for the excavation of the caverns, and estimation of the cost and manpower schedule to complete construction. This paper summarizes the results of the feasibility evaluation. The investigation was limited to modified hemispherical configurations ranging in size from 24.4 to 91.4 m (80 to 300 ft) in diameter. Two cavity support systems were considered. The first employs internally installed rockbolts as the means of primary rock support while the second involves the use of annular tendon galleries located above the chambers from which primary support members are introduced prior to general excavation. The internal support configuration was considered for cavities with spans of 24.4, 36.6, 48.8, and 54.9 m (80, 120, 160, and 180 ft) while the external support configuration was considered for cavities with spans of 54.9, 73.2, and 91.4 m (180, 240 and 300 ft).

Jan 1, 1979

By E. J. Beckman, R. M. Enick, C. Shi

A novel liquid-liquid separation for the recovery of free or liberated gold from mixtures of fine particles was evaluated. Two inexpensive and environmentally benign fluids were selected for the study, water and carbon dioxide. The separation, which is conducted at 295 K and at the vapor pressure of carbon dioxide (6.0 MPa), is based on differences in wettability between the precious metals and other minerals. Contact-angle results indicated that, in the presence of water and liquid CO2, gold is slightly hydrophobic. The addition of CO2-soluble fluoroalkyl thiols or f uoroetherthiols increased the hydrophobicity of gold exposed to water and CO2 to a greater extent than alkylthiols. Minerals, including quartz, pyrite and magnetite, were hydrophilic. During the separation, an aqueous slurry of fine mineral and gold particles was mixed with liquid carbon dioxide. Pure gold particles (-325 mesh) were found to agglomerate at the H2O-CO2 interface. The minerals tended to remain in the aqueous phase. Despite these promising preliminary results, very poor gold recoveries were obtained when applying the procedure to an Australian gravity concentrate. This was attributed to the native gold particles in the concentrate being either too large, agglomerated in slimes or coated with minerals. Although this particular application was unsuccessful, this water-CO2 biphase technique may be applicable for other separations that require the removal of very fine, hydrophobic particles from an aqueous slurry.

Jan 1, 2000

By J. Herhold, S. Plaum

"Increasing worldwide energy demands, coupled with desires for cleaner energy, have led to greater research of renewable energies. Strongly weather-dependent energy sources, e.g. solar and wind energy, are unable to provide a constant control energy to withstand the fluctuation of the extensive power systems during peak hours. The pump storage plant Nant de Drance in Switzerland will not only have the capacity of a nuclear power plant, producing 900 MW, but will also combine the environmental aspect and the demand for controlled energy. Nant de Drance is one of the pioneer projects for upcoming energy challenges and serves as a model for future pump storage plants. This paper focuses on the planning process and the project execution of interdisciplinary large-scale projects such as Nant de Drance, including project related data handling, communication systems and project handling skills. Furthermore, the paper discusses mining excavation in the context of large scale projects and their regional environmental challenges, e.g. high alpine rock mass on the site of Nant de Drance. PROJECT BACKGROUND Project Overview Nant de Drance is a 900 MW pump storage plant located in the Swiss Alps. To provide such a high energy storage, six turbines (reversible Francis type), each with a capacity of 150 MW, were installed. Due to the efficiency factor of 80% the pump storage plant is able to provide an energy production of 2500 GWh per annum. Construction of the pump storage plant, which has been selected as “Major Tunneling Project of the Year” in 2014 by NCE and ITA-AITES, will be completed over 10 years. Therefore, the project has been divided in six major phases outlined below: - Launch: 2008 - Access Gallery: 2010 – 2012 - Excavation KMA, KTR: 2011 – 2014 - Concreting KMA, KTR: 2014 – 2016 - Installation of HEM equipment: 2014 – 2018 - Tests & entry into service: 2017 – 2018 Figure 1 outlines the single process phases of the project. For the construction of the shafts, galleries and caverns, 1.7 million m³ of metamorphic rock with sedimentary origin (mica schist & paragneiss of the massif „Aiguilles Rouges“) were excavated. A tunnel network with a total length of 15 km was created. The machine cavern measures 194 m long, 32 m wide and 52 m tall."

Jan 1, 2016

By J. P. McDonald

Exposure to particulates containing metals and metal fumes (PCMMF) is a potential concern in ore refining and smelting. Some metals of primary interest are arsenic, cadmium, copper and lead, which have been linked to various adverse health effects. The current National Institute for Occupational Safety and Health (NIOSH) sampling method for metals in particulates requires the use of a filter, precision airflow pump and laboratory analysis. A major concern with this method is the one-to-two weeks? wait before laboratory results are available for use in determining if additional controls are needed to assure adequate exposure protection for workers. Particulates containing these metals were sampled during sixteen sampling events at a copper smelter using the traditional NIOSH methods. Monitoring of particulates was simultaneously conducted using a TSI 8520 Dust-Trak real-time aerosol monitor with a 10-µm-cutpoint sampling inlet. NIOSH analytical methods related to particulates and metals (methods 0500, 0600 and 7300) were used to determine particulate mass and individual mass contributions of metals on sample filters. Linear regressions with y-intercepts forced to zero were developed to determine the relationship between the PM10 measurements recorded by the DustTrak and laboratory-reported total particulate mass, PM10 and respirable arsenic, cadmium, copper and lead concentrations. These linear regressions yielded correction factors that can be applied to DustTrak readings to obtain total particulate mass, PM10 and respirable concentration estimates for each of the four metals. The R2 (coefficient of determination) values from the linear regressions ranged from 0.65 for total lead to 0.91 for total copper. These results suggest that the DustTrak may produce real-time data useful in providing estimates for airborne concentrations of arsenic, cadmium, copper and lead in copper smelter particulates.

Jan 1, 2011

By J. Espí

The mineral price assigned in mining project design is critical to determining the economic feasibility of a project. Nevertheless, although it is not difficult to find literature about market metal prices, it is much more complicated to achieve a specific methodology for calculating the value or which justifications are appropriate to include. This study presents an analysis of various methods for selecting metal prices and investigates the mechanisms and motives underlying price selections. The results describe various attitudes adopted by the designers of mining investment projects, and how the price can be determined not just by means of forecasting but also by consideration of other relevant parameters.

Aug 1, 2013

By James R. Taylor

24.1-BASIC PRINCIPLES JAMES R. TAYLOR The basic principle involved in maintenance is protection of a company's investment through the care and upkeep of machinery and equipment, buildings and properties. Maintenance is justified through making available to the maximum extent possible the facilities, machines and services required by the operating and production departments in their function of insuring optimum return on investment. As the size, cost and complexity of the equipment used in modern mining and related industries increase, operating and production personnel become proportionately more dependent upon maintenance engineering for its contribution to the overall profit picture. A greater part of the total cost now is charged to maintenance and the maintenance group becomes a major company unit. Basic maintenance concepts have changed very little over the years, but the advances in methods and technique have brought about tremendous challenge and have in consequence assumed a greater influence and importance. The older "sledge- hammer" methods have given way to engineered and scientific systems, while the accelerating development of intricate equipment and machinery, and the instrumentation essential for control, demand an ever-increasing upgrading of maintenance personnel. Regardless of this growth in importance, cost and complexity of the maintenance function, it is important to remember that it is not an independent and self-sufficient unit, but is a necessary facet of the entire plant operation and is subject to the company's total production effort. As one part of a team, maintenance is successful only when functioning cooperatively wit11 the other departments it serves Close collaboration in all areas served by n maintenance group is essential if it is to function fully to protect the company's investment, whether the assets are in machinery, materials or people. 24.1.1-MAINTENANCE SCOPE Maintenance functions may be grouped into the two general classifications of primary and secondary. This grouping constitutes a basic division although, in practice, the scope of the maintenance activity varies in each mine or plant and is subject to differences in size and type of operations and company policy, plus the influence of precedent, which may be sectional or industry-wide. The primary functions supply the justification for the maintenance engineering department. while secondary functions are variable according to plant conditions and needs. The primary functions may be categorized as follows: 1. Maintenance of existing machinery and equipment. 2. Maintenance of existing buildings and grounds. 3. Inspection and lubrication of equipment and machinery. 4. Utilities generation and distribution. 5. Alterations to existing equipment and facilities. 6. Installation of new equipment and facilities. 7. Instrumentation.

Jan 1, 1973

By K. E. Burgher

Since World War II, the need for the use of explosives in construction, mining, and quarrying near congested urban areas has increased dramatically. Often times a coal mine, once isolated from a city, finds itself surrounded by residential and commercial structures. The United States Bureau of Mines and others have researched blast design to a point where ground vibration and airblast damage can be avoided. A problem still exists, however. It is the fact that people often react to only the loud noise associated with a blast although it may not cause damage. Most often it is the concussion of a blast, less than 20 hertz and inaudible, that produces damage. Public fear from the "startle" and "fright" of loud blast noise greater than 20 hertz leads to the complaints which are generally unfounded. See Thackray, Touchstone, and Baily (1975) for a further discussion of the startle effects of loud sudden noises. When blasts are designed in accordance with U.S.B.M. specifications, management generally has little to worry about with respect to damage claims. Complaints, however, still arise when the noise is accentuated from the blast. It is meteorological conditions which dictate how the sound levels will propagate. Some mines use small pilot test shots (generally one-two lbs) to determine when atmospheric conditions favor sound travel.

Jan 1, 1987

By T. L. Owen

Since 1993 Cyprus Amax has brought $2.5 billion dollars of greenfield and expansion projects into production, taking it from a mid-sized domestic minerals company into a major international minerals organization. The near simultaneous development of these multiple mineral projects in different locations around the world provided the opportunity for Cyprus Amax to develop a formal project management approach based, in large part, on an outsourcing philosophy. This formal project management system along with its outsourcing philosophy has served the growth agenda of Cyprus Amax extremely well. These preceding factors, coupled with the in-house retention of a core project group that fully understands the breadth of skills and abilities needed to undertake development of multiple large projects successfully, have been the cornerstone of Cyprus Amax’s project development success.

Jan 1, 2000

By N. Kuroda

A realistic simulation model has been used for designing longwall mining, especially for solving operational problems. This paper describes background, development, validation and some applications of the simulation model for mining people who are unfamiliar with O.R. or computer technique, as a simple planning tool. The following items were established: logical analysis and algorithmic design for practical longwall mining, structure of hypothesis behavioral organism, input parameters, using practical knowledge and operational statistics of the mechanized longwall system experienced for many years.

Jan 1, 1982

By Peter Kowalczyk

The acquisition of submarine gravity data using airborne gravity technology is a practical reality. Ocean Floor Geophysics plans to deploy a free-swimming ROV based submarine gravimeter on a commercial basis in early 2009. The submarine instrument is a variant of the well-used GT-1A airborne gravimeter. Airborne gravity surveys are now routine. The primary factor controlling the accuracy of airborne gravimeters is the precision of the GPS measurement of vertical movement of the sensor platform. The gravity measurements along a flight line are the differences between the output of the gravimeter vertical accelerometer and the estimate of the aircraft vertical acceleration using the differential GPS system. The principle difficulty of moving an airborne gravimeter to a free-swimming submarine platform is the necessity to have an accurate real time estimate of the changing elevation and hence changing vertical acceleration of the platform; GPS doesn't work underwater and an accurate estimate of depth fluctuations to the necessary precision is difficult to acquire. It is interesting that the airborne gravity gradiometer technology, which competes with the airborne gravity technology, was first developed as a classified military application for use by missile submarines during the cold war. Gradiometers were developed for this application specifically to avoid this problem. A gradiometer does not require as accurate an estimate of its vertical position to make a useful reading- it measures gravity gradients, not the gravity field itself.

Jan 1, 2008