Planned strip-mined land reclamation that minimizes damage of the environment is vital for preservation of water quality, especially with present increased emphasis on coal production. Analysis of overburden is becoming mandatory in order to plan effective placement of material in spoil piles. One rapid technique with little sample preparation for determination of elements in overburden is scanning electron microscopy. This method was quantified in this study for determination of sulphur, potassium and calcium concentrations in cores from two watersheds in Raleigh County, West Virginia. These values were added to a water quality model to more accurately predict concentrations of elements in strip-mine drainage. Development of a method to predict elemental concentrations is helpful in determining potential environmental damage to a watershed. A correlation analysis was conducted using water quality data before and during mining to substantiate data received in the core analysis. Information as is determined in this study’ can aid mine operators in selecting potentially deleterious strata for subsurface placement and in retaining more environmentally beneficial strata for use on spoil surfaces. Knowledge of potentially hazardous substances in overburden should lead to more efficient revegetation procedures by surface mine operators. / Master of Science

No description available.

Thesis (MScAgric)--University of Stellenbosch, 2005. / Bibliography. Also available via the Internet.

M.Ing. (Engineering Management) / The design of the optimum open pit slope angle is one of the major challenges during open pit mine planning, as it implies attaining the ideal balance between utilizing the maximum slope angle whilst achieving acceptable stability and safety standards as indicated by the mine. The aim of open pit mines should thus be to seek the steepest possible slope angle without compromising the safety of the personnel, equipment or ore reserves, utilizing both stability analyses as well as risk assessments. The typical open pit mine plan aims to achieve an acceptable balance between operational risks and geotechnical design considerations by analysing factors such as the slope stability design, the rock mass properties and existing structural geological conditions. These factors are used as inputs towards an optimum slope angle design which will be used in the final pit design and aims to provide maximum economic viability to the mine. The risk analysis methodology aims to improve traditional slope design methods and is used to evaluate risks and failure consequences in terms of economic impacts. The economic impact analysis is a useful method in comparing the performance of various mine plans and slope designs. The risk analysis methodology thus provides a valuable indication of optimum slope design configurations and as such can be a great asset to the mine design process. This research paper aims to identify the key risks used as input to an open-pit mine plan in a feasibility stage and to define an approach to minimize these risks in order to achieve maximum economic benefit. The effectiveness of this approach will be evaluated by means of a case study which will attempt to achieve an optimum balance between value and risk, and to compare the magnitude of the economic impact of an individual risk with the probability of occurrence of said risk. The case study will utilise a risk map in order to define years with higher economic impacts as well as defining critical pit areas causing these risks, so as to identify areas requiring further investigation which will assist the mine in evaluating mitigation strategies in order to reduce overall risk.

Please read the abstract in the section 00front of this document / Thesis (PhD (Botany))--University of Pretoria, 2007. / Plant Science / unrestricted

An unstable slope in an open-pit copper mine in Arizona was analyzed after a 250,000-ton slope failure had occurred. Data on all available time-dependent hydrogeologic factors were analyzed utilizing multiple regression techniques in order to build a mathematical model of the slide displacement. This allowed determination of those factors which were most influential in promoting instability. It was determined that a ground-water rise of approximately one foot, and rainfall in the week prior to the failure, were the most important factors contributing to this particular slide. This is believed to be due primarily to an increase in cleft-water, or hydrostatic, pressure, with seepage forces contributing a significant but relatively constant shear component. Because instability was observed to extend beyond the original slope failure, a dewatering analysis was undertaken. A steady-state finite element flow system model series was developed by progressively incorporating subsurface information, as well as water table location. The ground-water flow system within the granitic host rock was then simulated as a continuum, and a flow net derived. Analysis of this flow net, combined with known ground-water discharge into the open pit, comprised the basis to estimate the coefficient of permeability to be approximately 4 gallons/day/foot². This value was then utilized in a preliminary dewatering analysis incorporating standard aquifer equations to predict possible drawdowns. The computed drawdowns suggest that pumping rates on the order of 10 gallons/minute/well from a line of 12 wells spaced 50 feet apart would produce approximately 100 feet of drawdown after 1 year of pumping. Results of stability analyses for various ground-water levels indicated that when the water table is lowered by dewatering, a steeper slope could be maintained in the open pit. Such steepening could be as much as 1° when the water table is lowered one-half to one-quarter the height of the slope (135 feet), and approximately 4½° when the slope area is completely drained.

Natural factors limit the extent to which land disturbed by man's activities such as the strip mining of coal may be returned to productivity. In the western United States, the availability of water is frequently the most important of these factors. To assist decision makers in land restoration efforts, a procedure is developed by which precipitation and the distribution of precipitation water on reclaimed areas may be forecast. With this information, reclamation decisions can be made with increased confidence. The initial phase of the procedure is the development of a sequence-based stochastic precipitation model which provides as output simulated sequences of annual precipitation events. Probability distributions for storm parameters such as precipitation per event, event duration, distribution of events in time, etc. are obtained from analysis of historic climatological data for the study area. From these distributions simulated series of annual events possessing statistical characteristics of the actual event sequences are generated. Statistical analysis shows no significant differences between parameters of the actual events and those generated by the model. The stochastic precipitation model is used to drive a deterministic model simulating other hydrologic processes. In the second model, a finite difference solution records changes in water content within the soil profile. Root extraction, evaporation, infiltration and percolation are also simulated based upon changing hydraulic head at selected depth intervals. The kinematic wave approximation and the continuity of mass equation are used to route overland flow from the watershed. The model accurately predicts the distribution of water resulting from annual series of precipitation and potential evapotranspiration event sequences.

In this study the shear strength parameters for a consolidated, well-cemented boulder conglomerate at the Cyprus Miami Copper Mine are determined by a newly developed field test. The values obtained are used to investigate the probability of failure of pit slopes cut into the conglomerate. Any boulder conglomerate is impossible to test accurately with conventional laboratory techniques due to its large particle sizes and the destruction of cementation by conventional sampling methods. For these reasons a simple in situ test was developed which could be used in conjunction with laboratory techniques and analytical procedures to estimate the in situ strength properties of the Gila Conglomerate. The variability in the testing of the shear strength parameters of Gila Conglomerate make a probabilistic approach to design appropriate.

No description available.

Thesis (M.A.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains vii, 56 p. : ill. (some col.), maps (some col.). Vita. Includes abstract. Includes bibliographical references (p. 50-55).