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By S Yuen, T Rana, S Khan

Many open pit mines require dewatering or need aquifer depressurisation systems to manage mine water inflow and/or mine floor stability. In many instances these mining operations impact on regional groundwater resources and therefore access to these resources by other users.As such potential exists for mine development to be hindered or even blocked by groundwater legislation that aims to prevent declining groundwater levels and demonstrate equitable use of a regional groundwater resource.There is a need to manage aquifer systems during and after the mining operations, and in some cases stresses on the aquifers and associated ecosystems may be elastic and can be managed with minimum impacts or reversed once the mine ceases to operate.This paper uses the Gippsland sedimentary basin, with a history of declining groundwater levels and mining and petroleum production, as a case study to pose the question: Should period of mining operation, aquiferÆs storage capacity and its ability to recharge be concurrently considered when granting groundwater abstraction and mining licenses for prospective mine development?It further examines that by utilising an aquiferÆs storage capacity and demonstrating an understanding of aquifer system hydrodynamics during and beyond the life of the mine (time), the approval process for groundwater abstraction and associated cost of statutory monitoring may be made less onerous.

Jan 1, 2009

Experiments on High Efficiency Separation of Mixed Plastic Wastes by Vortex-Tube Separator

Sep 13, 2010

Advances in Thickener Feedwell Design via Computational Fluid Dynamics Modelling

Sep 13, 2010

By Keith A. Heasley

Numerous different instruments and techniques have been developed for the purpose of measuring rock stress and stress changes around excavations. The interpretation of the output from many of these instruments has often been problematic. This paper covers the research performed in attempting to analyze one particular stress measuring instrument called the Borehole Platened Flatjack (BPF) . The approach used in this analysis was to combine the analytical solution for the displacements around a borehole and the analytical solution for the bore- hole-platen interaction with the empirical stiffness behavior of the flatjack. The resulting model of the BPF response was then verified using measured laboratory data with very good results. In addition, techniques for applying the method to the field are briefly discussed. The major accomplishments of this comprehensive modeling and testing program are; 1) the establishment of the critical installation and site parameters of the hydraulic pressure cell and 2) the development of a systematic procedure for calibrating the cell based on the given values of these critical parameters.

Jan 1, 1989

By W. D. Northrop

This paper gives an account of the development of a technique whereby the vertical limits of geological horizons may be identified by the use of vertical variograms on the mineral of economic interest. This information may supplement or guide the correct subdivision of the individual horizons into meaning full data sets by diligent geological observation. This process then improves the quality of the variance modelling of the gold distribution in the plane of the individual layers and therefore enables better estimates to be made into the grids or blocks of the mine model. The technique is explained by an account of the development work, which was performed, on duplicate superimposed reef horizons in the Kimberley formations. The paper then shows how the correct approach was developed to evaluate the mineralized layers in a multiple stacked conglomerate layer sequence in the Elsburg reefs of the Witwatersrand Rand System at the Target deposit. The method of categorization of resources according to confidence in the estimate is also explained. The feasibility processes carried out on the three-dimensional model, in accordance with the SAMREC code are also described. An example of the development of a reconciliation process utilizing chip sampling is also explained.

Jan 1, 2003

By C J. Adams, H J. Campbell, A J. Tulloch, I J. Graham

New Zealand can be regarded as a rifted part of mineral-prospective eastern Australia. Geologically credible comparisons between selected trans-Tasman and SW Pacific geological provinces and units, especially those that contain significant mineralisation in Australia, can help provide a useful exploration framework for New Zealand. As part of a six-year Mineral Wealth of NZ and its EEZ (MWE) research programme, we have targeted selected geological units in eastern Australia for comparison and contrast with their potential New Zealand counterparts. In future years, the programme will focus on geological units in New Caledonia.

Jan 1, 2005

THE filter-press, which has done so much for the successful treatment of the sulpho-telluride ores of Kalgoorlie, has a serious rival in the vacuum process, and this paper is written with a view to arousing more interest in the cheaper working of the press, it being doubtful whether its efficiency in extraction can be improved upon.Before proceeding with the actual working of the press, it may be as well to make brief mention of the character of the ore treated at the Associated Northern Blocks, where these notes were compiled.A sample from several weeks' run was taken of the raw ore, with the following analysis...

Jan 1, 1910

By G. J. Hasenfus

This paper presents the results of an extensive hydrological and geomechanical monitoring program which Gas conducted at a longwall coal mine in W. Va. The field program included monitoring of groundwater levels. overburden hydraulic conductivity, overburden movement, and surface subsidence relative to the passage of the longwall. Overburden geology and rock strength characteristics were evaluated prior to mining. A postmining corehole was drilled to evaluate main roof fracturing. An overburden response model is proposed based on the correlations between hydrological and geomechanical data.

Jan 1, 1988

By Leslie F. Ruppert

The US Geological Survey (USGS) is currently conducting a coal resource assessment of the coalbeds and zones that are projected to provide the bulk of the nation’s resources for the next few decades. The Pittsburgh and Upper Freeport coals are the first two beds in the northern and central Appalachian basin region to undergo fully digital coal assessments. The bed-specific assessments are being carried out in partnership with the state geologic surveys of West Virginia, Ohio, Pennsylvania and Maryland. Comprehensive stratigraphic and geochemical databases have been developed for both of the beds. The extent of the bed with mined areas, structure contour, isopach, and overburden thickness maps for the Pittsburgh coal bed have been released as USGS open-file reports.

Jan 1, 1999

By Yushiro Hirai

Saganoseki smelter & refinery had operated two flash smelting furnaces from 1973, attaining 330,000 mtpy of copper production in 1989. In 1996, however, it carried out a "integration of two flash furnaces". That is, it doubled the feeding capacity to one flash furnace to shut down another furnace while maintaining the same production. Single flash furnace operation has successfully started in March 1996 accomplishing a great reduction of the total production cost. The production had reached to 350,000 mtpy in 1997, and further increased to 450,000 mtpy by executing the expansion program with single flash furnace in 1998. This paper introduces results of the single flash furnace operation and describes about an outline of the expansion.

Jan 1, 1999

With unprecedented worldwide growth and increasing global demand for energy expected to swell by 60 per-cent in the next two decades, mining matters as much now, if not more, than it ever has. This was the consensus at the 110th Annual National Western Mining Conference presented by the Colorado Mining Association, Feb. 12-14 at the Westin Hotel in Denver, CO. The role of coal ? America?s most abundant energy source ? the future of uranium and its possible resurgence in the energy marketplace, the skyrocketing value of gold as well as the issues of health, safety, climate change, legislation and government?s role in mining were all discussed during the three-day conference that operated under the banner of ?Mining Matters.? Barbara Filas, chairperson of the 110th National Western Mining Conference, president of Knight Piesold Co. and former SME president, welcomed the record crowd with an inspiring speech in which she pointed out that although ?most normal folks don?t know what role mining plays in their everyday life, mining does matter. ?Our industry,? she said, ?matters to Colorado. It matters to Colorado because it is a $3-billion industry. It matters to the 13,000 people who are employed directly or indirectly by the industry and it matters to schools that receive more than half of the royalties that are generated by mining.? During discussions of mining?s place in Colorado, the western United States and the world, special attention was paid to coal, uranium and the future of energy. ?It is time to rethink our perceptions about coal,? said Mark A. Smith, president and chief executive officer of Chevron Mining Inc. He spoke during the opening reception in a presentation titled, ?Coal to Liquids: Bridging America?s Energy Gap.? Although coal is America?s most abundant, and cheapest energy source, it is also one of the most scrutinized because of the pollution it causes and recent, and heavily publicized, tragedies that have claimed the lives of some who mine it.

Jan 1, 2008

By A. U. Miller

"Ventilation is one of the meet important factors in mining, although until recent years less thought has probably been given to effective ventilation than to any other one phase of mining. In the past, very little, if any, attention was given air courses until they became so constricted by falls that the volume of air was greatly reduced; and, in addition, the stoppings and doors were so poorly constructed that only a very small percentage of air reached the face workings.As a matter of fact, mines have been visited where the volume of air being circulated in certain sections was much larger than in others, and where the management was striving to increase the flow of air in those sections with the least air current, believing the ventilation to be deficient. After sampling and analyzing the return air from the various sections in such mines it has been found that the quality of the air in certain places with the largest flow was more impure than in some of those with the least flow.In past years, practically all mine fans were operated by steam-driven engines supplied with steam from the mire boiler plant. No check was made on the steam consumption or the power cost of operating the fan, therefore the management had very little if any definite information as to cost of ventilating the mine.With the increased use of electrically-driven equipment in mines electricity is being used more and more to drive mine ventilating fans, and since in many instances the current is purchased from central power plants operators have come to realize that in many cases the cost of operating the fans is very high. Some engineers estimate that it ranges from 20 to 50 per cent of the total power cost of the mine. This information, together with the fact that mines are now being developed on a larger scale, requiring larger quantities of air for the men to dilute the gases liberated, has caused the large progressive companies to make, a more comprehensive study of mine ventilation, resulting in a decided improvement in the quality and quantity of air at the face workings, as well as reducing materially the ventilating costs."

Oct 1, 1930

By Verya Nasri

This paper presents analysis of damages and rehabilitation design for three major French rail-way tunnels built in mid-19th century. The La Nerthe tunnel underwent ovalization deformation with excessive displacement at the springline, and pinching and bursting of the liner bricks at the crown due to tectonic residual stresses with very high lateral earth pressure. The Saint-Louis les Aygalades tunnel invert was subjected to undulatory deformation resulting in tracks misalignment, which was caused by non-homogeneity of mechanical and hydraulic properties of the ground. The Roches de Condrieu tunnel required widening to comply with the increase in dynamic envelope of trains due to their larger cross section and higher speed. The applied rehabilitation methods and constraints of work in these busy mainline railway tunnels have been discussed in detail.

Jan 1, 2008

By K. S. Liddell

Ultra fine grinding is becoming increasingly used in the mining industry over recent years. The development of large-scale units for high volume grinding of low value materials and concentrates has opened up new areas of economical metal extraction. The ability of stirred vertical mills to produce very fine particles with high surface areas, is providing mine operators with novel extraction possibilities within gold concentrate regrind for Biox or leach feed, Activox autoclave feed preparation and lime slaking operations. The paper will review design, operational and maintenance aspects of ANI-Metprotech stirred vertical mills, comparing these to tower mills, horizontal bead mills and attrition mills.

Jan 1, 2001

THE Talisman mine is situated on the Waitawheta (pronounced Wytaffetta) river just above its junction with the Chinemuri (pronounced Chinnemurre) river near Karangahake, NZ. The explored reef-bearing portion of the claim includes the angleformed by the junction of the rivers and extends southwards for slightly over a mile (See Plate V.). The country is mountainous both rivers flowing through precipitous gorges.The trig. station on Karangahake mountain is almost directly above the workings on the Bonanza section and is 1680 ft. above river level, the adit from the gorge giving 1200 ft. of backs measured vertically. The officers of the N.Z. Geological Survey are engaged in a detailed survey of the Waihi district and the rocks of Karangahake are under examination. The rocks of the district are andesites and dacites much altered and silicified. One of these exhibits a columnar structure in the mass in the Waitawheta gorge near the surface workings on Taukani hill, also on the southern bank...

Jan 1, 1912

By Albert W. Deurbrouck

The performance characteristics of five hydrocyclone coal washers were evaluated to determine the sharpness and efficiency of separation that might be anticipated in commercial operation. The hydrocyclone overflows contained generally good clean coal products that would require little re-treating to remove misplaced high-gravity material. The underflows, however, contained from 63.6 to 36.7 percent of misplaced low-gravity material, which would require secondary cleaning to provide acceptable clean coal yields.

Jan 1, 1974

By R. G. Bentsen, D. A. T. Donohue

The cyclic steam injection process has become the most widely applied and most successful thermal recovery technique in use today.1-4 Normally, steam stimulation is repeated several times during the life of a project. The problem is to select the optimum number and size of steam treatments so that the profits realized over the entire life of the project are maximum. Obviously, operating costs rise directly with the frequency and amount of steam injection. Operating efficiency, on the other hand, can be adversely affected if the amount and frequency of stimulation are insufficient. Thus arises a multistage decision problem; that is, a decision must be made at each sub-period (day, for example), as to whether steam should be injected, and, if so, how much. It is desirable that these decisions be made in such a way as to secure maximum net profit before taxes. This can be achieved by dynamic programming. To use dynamic programming, we must be able to predict not only the production rate-time curve resulting from a given stimulation, but also how changes in stimulation policy will affect this curve. In this study, the effect of steam injection on well performance is estimated on the basis of a simple model that takes into account both steady-state and transient flow. Oil production rate is calculated for both types of flow, and the larger of the two values is used. This allows the calculation to change to radial steady-state flow at such time as this mechanism becomes more effective than the transient mechanism. We propose to show how dynamic programming can be used to optimize the steam soak process with respect to net profit. For this, a mathematical representation of the steam soak technique is necessary. A further objective, therefore, is the formulation of a mathematical model capable of realistically simulating the physical process. Oil Production Response Model The advantage of using a mathematical model is its generality and ease of manipulation. However, the model must be an accurate representation of the physical process, for a solution derived from a model can be no better than the model itself. The question now arises as to how well the model should be expected to simulate reality. In general, the simplest model should be tried first, for additional accuracy is apt to require additional cost and time. Also, the search for a high degree of accuracy may yield only greater complexity and difficulty without yielding significantly better results. With this in mind, we kept our model as simple as possible, yet generally representative of the actual physical process. The number of state variables is limited to three, and stochastic variations in the parameters are ignored. As a consequence, use of this model should be restricted to cases in which the underlying assumptions are not severely violated. In

Jan 1, 1970

Rock mass classification is widely used throughout the underground mining industry—in both coal and hard-rock mines. It is used in all stages of the mining process, from site characterization to production operations. The goal of the International Workshop on Rock Mass Classification in Underground Mining was to provide a forum for leading practitioners of rock mass classification to come together and share their methods and experiences with the technique. The workshop was held in Vancouver, British Columbia, Canada, on May 31, 2007. It was co-chaired by Christopher Mark, Ph.D., P.E., National Institute for Occupational Safety and Health, Pittsburgh, PA, and Rimas Pakalnis, P.Eng., University of British Columbia, Vancouver, Canada. The proceedings of the workshop contain 16 invited papers from 9 countries, reflecting the international depth and breadth of current practice. Applications in both hard-rock and coal mining are well represented. Some of the topics that were addressed at the workshop include: • Major rock mass classification systems used in mining and their variants • Collection of input data through observation, rock testing, and geophysics • Design of mine layouts and rock support systems using classification • Estimation of rock mass strength and other input parameters for numerical models from classification • Applications in weak rock, raise boring, cavability assessment, and other special topics • Risk assessment using rock mass classification

Jan 5, 2007

OWING to the gradual depletion of the hitherto plentiful supply of firewood in the immediate vieinity of Queenstown and Gormanston, which caused a steady increase in the cost of fuel for domestic purposes, the Mount Lyell Company took steps several years ago to make available as a substitute electric current from its Lake Margaret hydro-electric supply. In order to make this practicable it was necessary that the cost of electric power for heating purposes should compare favourably with the cost, of fuel, and the installation of domestic appliances brought within reach of the average householder, and efforts have been continuously directed towards this end since the year 1928.WATER HEATERSThe installation of electrical apparatus in local dwellings began with hot-water services, the heating elements being the types then procurable on the market and adapted to meet requirements.These, however, did not prove satisfactory, but the study of their bilure resulted in a type being developed locally which has overcome all difficulties. The first type of water heater evolved was an outside circulation one the element of which consisted of an iron pipe through which the water passed, insulated with micanite and wound with nichrome wire, the latter being covered with alundun cement to keep it in position and prevent oxidation. This was insulated on its outside surface with a layer of asbestos flour, and connected to the hot-water container as shown in Fig. 1. It was found, however, that the iron pipe had a short life, due to a certain amount of acidity in the water, and a copper pipe was substituted which proved very durable. Some heaters with this improved type of element are still operating after six years of use. The resistance wire is run at a very low current density, which ensures durability.

Jan 1, 1927

By Peter Wells, Laxman M. Amaratuga, Todd M. Kanhai

"Certain mining methods (eg. Cut-and-fill) result in the contamination of run-of-mine ore with shotcrete. This shotcrete remains mixed with the ore throughout processing. Experimentation performed by Falconbridge Limited revealed that underground contamination of ore by shotcrete (eg. as little as 1% by weight) has led to ill-effects on the nickel recoveries from the flotation process in the mill. The nickel recoveries of contaminated samples were lower than tests without the shotcrete Contamination.To optimize flotation circuits it is important to know why the contamination has created these effects and also to find a method to abate or remove them. Laboratory testing showed that the age of the shotcrete was a factor in it’s effect on nickel recoveries. Younger aged shotcrete gave nickel recoveries lower than baseline nickel recoveries with no contamination. Older shotcrete gave nickel recoveries similar to the baseline.Literature on other cementitious material contaminations on ore revealed that a possible means of remediating this problem is the use of acid in the flotation. The initial pH in the flotation pulp was designed to be pH 9.2, but with the young shotcrete contamination the pH was in the neighbourhood of 10.5. Acid addition may act as a means of lowering the pH to the optimal operational value. Laboratory test work showed that acid addition brought nickel recoveries closer to the baseline."

Jan 1, 2000