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By S. Frimpong

Hydraulic shovels are widely used for primary production in surface mining operations. Variability in material diggability, unstructured mining environments and limited space and operator inefficiency affect the performance of these shovel excavators. Dynamic models of the hydraulic shovels are essential for understanding and improving machine performance. This paper contributes to this subject area by advancing hydraulic shovel kinematics and dynamics using the modified Newton-Euler method. A virtual simulator is developed to simulate the hydraulic shovel performance in the ADAMS environment. The simulator is validated with data on shovel geometry and the physical and mechanical properties of a formation in a surface mining environment. The results indicate that a shorter digging time increases the shovel operating power requirements, and that the required peak power increases by 100% when the digging time reduces by 50%. Simulation results also show that a shallow trajectory facilitates the digging process, with 50% reduction in peak power requirements compared to a deep one. This simulator provides a powerful tool for performance monitoring, excavation process designs and structural optimization of hydraulic excavators. This work also forms the basis for developing comprehensive simulator models for automated shovel operations in constrained mining environments.

Jan 1, 2005

By Ian Misich

Surface subsidence resulting from "total extraction" of coal in the Collie Basin first occured in 1987 when Western Collieries Ltd trialed the Wongawilli mining method. Because very little quantitative subsidence data existed for the weak, Permian sediments, a research program was set up prior to the extraction of the first panel. The objective of the study was to be able to predict subsidence characteristics and effects prior to mining future total extraction panels. Attempts at predicting subsidence began using existing subsidence models from other coal mining regions, however, as more site information became available, it became clear that it was necessary to develop a separate, site specific predictive model for the Collie Coal Basin. Analysis of extensive field monitoring data for both surface and subsurface subsidence has produced a series of empirical models which can predict the shape of surface subsidence troughs and corresponding tills, and strains for rectangular panels and describe the sequences of ground movement from the mine root through to the ground surface. The fact that both subsurface and surface subsidence characteristics have tied in well, gives greater confidence for predictions made from these models

Jan 1, 1992

This paper presents a resume of the likely profitable mining areas in New Zealand. It covers the main 'minerals' û gold, coal, oil and gas, ironsands, silica sands, clays, lump silica, perlite, sulphur and limestone. The potential mining projects are depicted on a map of New Zealand together with the associated works involved in hydro-electric and geothermal power development requirement for industries such as aluminium, nickel ferro-silicon or silicon carbide production. The political need for mining development to relieve unemployment and reverse emigration is stressed. A case is made for exploration and development assistance by government in labour re-training, energy supply and transportation, if the tremendous losses through lack of use of human and industrial resources are to be rapidly reduced. These losses are currently estimated at $10 000 000 000 per year. The need for protection of the sanctity of contract and security of tenure of all mining operations is touched on briefly as is the need for a reasonably balanced view on conservation. However, as both of these are more properly covered in papers on the legal and environmental aspects of the mining climate, they are presented here only as they affect the economy of the mining operation. Finally, there is a brief comment on the mining climate in New Zealand relative to Australia and South Pacific mining operations.

Jan 1, 1990

About twelve months ago, owing to the increasing quantity of stone and dirt being drawn frQm the Victorian State Coal Mine due to the large amount of dead work below ground, cutting, faults, etc, and to the increasing quan#ty of banded coal beingworked, the writer was forced to consider the question of economy in handling the spoil at the surface. The method in operation at the time was to run out level dumps fro,m the, tipping floor of the heapstead, or brace, and to tip most of the skips of stone in tipplers at the ends of the dumps, the remainder of the skips being side-tipped to widen the dumps.The method, whilst quite satisfactory for dealing with a few skips of stone, was found to be costly as the dumps extended, and the number of skips to be dealt with increased from 300. to 400 per day of two shifts;. therefore, in order to expedite thework and cheapen its cost, the writer devised an improved method which may be qescribed as follows :-(1) The stone is tipped into a hopper car which holds about 10 skips(2) The hopper car is hauled up an inclined dump by means of an electric winch.(3) The spoil is dumped from the car forwards or to either side, as required.(4) The car is returned to the starting point for a further load.Plate I Fig. 1 gives an idea of the construction of the hopper car. In the illustration the car is in position for tipping to one side. The body of the car is supported on a ball race on the under carriage, and it can be swung round to tip in any required direction. The bottom of the hopper is extended to form a 4 ft. lip...

Jan 1, 1918

By H. Kose

In this research, a model quarry with an annual production capacity of 1 000 000 tonnes has been studied for both pit and hillside quarry cases with constant overall slope angle and variable bench slope angle, considering road grades of 8 per cent and 10 per cent. First, technical requirements have been determined and then the effect of production parameters, such as hole diameter, type of quarrying (pit or hillside) and road grade, on the cost has been investigated to determine bench height. Based on the results, it has been concluded that hole diameter has to be kept large in both pit and hillside quarrying to reduce drilling unit costs. In addition, in order to take advantage of gravity and reduce transportation cost, it has been suggested that bench height and road grade have to be kept high and low respectively in the case of hillside quarrying (downhill transportation) while, in the case of pit quarrying (uphill transportation), bench height and road grade have to be kept low and high respectively, in order to transport the blasted material to a lower height and distance, to save energy, thus decreasing the transport cost. Keywords: Quarry, pit, hillside, road grade, bench height

Jan 1, 2005

By Jason Ryan, Stephen Harria

Q.E.D. (QED) is a blast design and evaluation model that allows full three-dimensional design specification including the development of unique “live” terrains and an unlimited variety of complex charge configurations. QED’s analysis package allows the examination of likely outcomes resulting from changing various design variables in terms of vibration, fragmentation, rock-mass damage and muck-pile profile. Especially applicable to use cautious blasting applications, QED’s damage model uses vibration to estimate rock damage beyond excavation boundaries. This relates directly to operations such as Yucca Mountain Nuclear Waste Repository in Nevada, where damage beyond the excavation perimeter must be tightly controlled. The U.S. Department of Energy (DOE) h as b een studying a site at Yucca Mountain, NV to determine its suitability for long term storage of nuclear waste. The main mechanism of waste isolation will be the natural barrier of the host rock Total Systems Performance Assessment (ISPA) is used to model the excavation design and its behavior over time. Of importance to TSPA is quantifying the condition of the rock-mass before and after excavation. Ideally, there should be no excavation-induced changes to the rock-mass’ structure (removing the requirement to model the effects). At the least it may be possible to keep excavation-induced damage far enough away from waste packages so that modeling of these effects will not be required. QED can calculate a prediction of the extents of blast induced damage to the rock-mass. By using this metric as a design parameter, it may be possible to complete excavation of the repository more rapidly and inexpensively than previously thought, without jeopardizing the structural integrity of the waste containment areas or requiring blast damage to be modeled by the TSPA. This paper will explain the structure of the QED blast modeling system and show the analysis of historical data from Yucca Mountain. Processing of the historical data and the subsequent results will demonstrate how blast modeling can be used on an ongoing basis to assist the excavation process at Yucca Mountain.

Jan 1, 2000

By P.J. Terbrugge

Open pit slope design has conventionally been effected as a bottom-up function utilizing available geotechnical information. This results in a decision criterion based on probability of failure and factor of Safety with a risk assessment being carried out on the proposed design slopes. The design approach recommended reverses the process using fault event tree decision methodology. The consequences of this approach are that acceptable risk criteria have to be determined by mine owners. Slopes are then designed by the technical staff to achieve these corporate goals. Benefits that arise from the process are that the owners take a proactive decision on the risk-benefit relationship allowing the technical staff to optimize the geotechnical exploration programme and design.

Jan 1, 2006

By Leandro Echavarría

El presente texto describe el sistema epitermal de Arcata, situado en Arequipa, Perú. Arcata es un distrito epitermal de sulfuración intermedia rico en plata y metales base, cuya mineralización se hospeda en vetas de rumbo predominante noroeste y movimiento principal paralelo a la inclinación que forman una estructura de fosa (graben). Las vetas poseen texturas de relleno de espacios abiertos como bandeados costriformes, en cucarda, crecimientos en peine y brechas, con ganga de cuarzo, calcita, rodonita y rodocrosita. Por su parte, los minerales de mena más comunes son galena, esfalerita, calcopirita, con los metales preciosos hospedados en sulfosales de plata (pirargirita y tetrahedrita). Asimismo, se ha identificado una compleja secuencia paragenética con varios pulsos responsables de la mineralización económica.

Apr 22, 2003

Laboratory-Scale Magnetohydrostatic Separator for High Resolution Density Analysis of Plastic and Other Wastes Recycling and reuse of different plastic wastes is still a current problem to solve for process engineers and it is true for seeking industrial applications as well as for smaller laboratory-scale, where a given waste sample, plastic or even metallic, has to be precisely separated into narrow density fractions to gain data for industrial design or for scientific research. The principle of magnetohydrostatic separators are known even there are industrial size machines but our primary aim was the development of a laboratory-scale separator for analysis of particles of densities up to 6 kg/L and sizes up to 8 mm. Main parts of the built experimental equipment are the ferrite core with two high power coils. The shape of the ferrite core at the two sides of the separator channel was specially designed to produce isodynamic magnetic field. In these places the ferrite core was constructed from laser cut ferrite sheets. The development of the high power electric supply for the two coils was a real challenge because the high voltage and current (400 V, 30 A) and because it had to be precisely regulated for being able to set discrete relative forces on the particles. Two separator channels were made from transparent plastic. The magnetic fluid is circulated by a centrifugal pump, fresh feed is supplied by a vibrated feeder and products can be taken by built in samplers. The velocity profile in the separator channel is measured by an ultrasonic Doppler velocity meter. Paper reports about the development and itself of the magnetohydrostatic separator and about some fundamental and applied laboratory experiments with different reference particles and wastes from used cars and electrical appliances.

Sep 13, 2010

This study was conducted to establish the effects of a diesel particulate filter (DPF) system with sintered metal substrate on the concentrations and size distributions of nano and ultrafine aerosols and concentrations of nitric oxides in underground mine air. The study focused on the formation and transformation of nucleation mode particles in mine air under prevailing test conditions. Experimental work was conducted in the NIOSH Diesel Laboratory at the Lake Lynn Laboratory experimental mine, a facility developed to allow evaluation of control technologies directly in underground conditions. The DPF system was examined for four repeatable steady-state engine modes using a naturally aspirated mechanically controlled Isuzu C240 diesel engine fueled with ultralow sulfur fuel. The engine coupled to an eddy-current dynamometer was operated in the underground drift with tightly controlled ventilation. Measurements upwind and downwind of the exhaust system discharge were used to quantify the effects of the DPF system on the mine air. A baseline was established using a standard muffler. The study showed that sintered metal DPF systems reduced the total mass of aerosols in the mine air by more than ten-fold when compared to a muffler. The nucleation mode aerosols (50dem<40 nm) in mine air were found to be strongly influenced by engine operating mode. The concentration of nucleation mode aerosols was found to be significantly higher for high-load modes than for low-load modes. The muffler and DPF system resulted in comparable total nitrogen oxides (NOx) concentrations. However, the nitrogen dioxide (NO2) fraction of the total NOx was found to be substantially higher for both systems for low-load modes than for high-load modes.

Jan 1, 2009

The Bureau has published much data on sulfur (4, 15, 23)3, most of it dealing with national or international aspects of the sulfur industry. Little information, however, is available on sulfur marketing in specific States or areas, Therefore, the Bureau has conducted a survey of the resources, production, consumption, and economic future of the sulfur and sulfuric acid industry in States of the Central and Southern Rocky Mountain area - Wyoming, Colorado, Utah, Arizona, and New Mexico - and in the Northern Plains States - North Dakota, South Dakota, and Nebraska, even though these States do not represent an economic or marketing unit. The purpose of this survey is to review the demand for sulfur and primary sulfur compounds that draws upon the natural resources of the region, to discover opportunities for better use of these resources, and also to analyze and evaluate the patterns of consumption, sources of supply, and other factors that affect the demand for these mineral products. While this survey stresses the economic and marketing phases of the industry, a complementary report (32) emphasizes the resources of sulfur in Wyoming, Colorado, Utah, New Mexico, and Arizona.

Jan 1, 1962

By R. Karl Zipf

Highwall mining is an important surface coal mining method, and it may account for approximately 4% of total U.S. coal production. Highwall stability is the major ground control related safety concern. Ground control plans for highwall mining should specify hole width, web pillar width, barrier pillar width and number of holes between barriers. This paper offers simple design charts for these parameters aimed at providing “ball park” checks. Web pillars containing pre-existing auger holes are analyzed and a design chart for estimating their minimum width is also presented. Finally, close proximity multiple seam highwall mining, which may have caused several serious highwall failures, is analyzed. Web and barrier pillar recommendations for this special situation are presented.

Jan 1, 2005

By P. S. Heyns, M. Heyns

A computer model has been developed of mine hoisting systems in deep South African gold mines. Particular attention was paid to the contribution of different modelling assumptions for the guides and guide-roller assemblies. Objective functions indicative of guide-roller tyre endurance, slipper-plate forces and perceived vibration levels were introduced to quantify dynamic performance. These objective functions were used to compare models. It was found that the choice of guide and guide-roller models did not influence the forces on the guide rollers significantly for typical shaft and conveyance characteristics at typical levels of viscous damping coefficients. The rigid and finite-element guide models gave the same results as those of the effective-stiffness guide model, and while the latter is suitable for simulation for design purposes, the finite-element model should be used for unusual guide geometries

Jun 19, 1905

Predicting Water Recovery from Flotation Cells

Sep 13, 2010

By Ernest A. Curth

The Bureau of Mines and Old Ben Coal Co. concluded a cost-sharing contract in 1975, the objective of which was to demonstrate the Herrin No. 6 coalbed in southern Illinois can be mined safely by longwall methods. Under the agreement, three longwall panels are to be mined at Old Ben No. 24 mine. A premining investigation laid the groundwork for specifying a roof-support system designed to control hazardous ground. Old Ben Coal Co. and Bureau engineers selected lemiscate-type roof shields. A rock mechanics program and geological mapping provide early warning capability and criteria for future equipment design. The effect of mining on the surface was monitored by a surface survey to develop subsidence-prediction criteria for the Illinois coal basin. The first of the three longwall panels started up in September 1976 and was completed in May 1977. The major adverse condition was the occurrence of limestone concretions, called coal balls, in massive pods. The shields provided adequate roof control even in faulty ground. Operation of the second panel started on August 1, 1977, following panel-to-panel transfer of the equipment. The accident rate was low.

Jan 1, 1978

By Clyde Baker

Drilled shafts for many situations offer an economical alternative to driven piles. The Federal Highway Administration (FHWA) has spent considerable time and money in research and developing design and construction guidelines for drilled shafts. However, the full potential of the technology may not be realized because of the uncertainty of the effects of construction on the actual service behavior and the lack of either reliable quality control tests to check for or evaluate defects, or inexpensive load test procedures. Static load testing is very expensive and it is not feasible to load test each shaft on a project. Therefore, other means are necessary to confirm or evaluate the integrity of the completed drilled shaft or to determine the capacity of the completed shaft.

Jan 1, 1989

By P. Share

As part of JAGUARS (JApanese-German Underground Acoustic emission Research in South Africa), high-resolution tiltmeters were installed during 2007 at Mponeng gold mine, South Africa, in an attempt to study and understand the risks posed by in-mine seismic events and to subsequently use the knowledge gained to mitigate these risks. In December 2007, an M2.2 event occurred at Mponeng and was detected by the tiltmeters installed. The tilt expected for the M2.2 event is modelled through the use of numerical and analytical tools and utilizing, as input parameters, characteristics of the event such as the rupture area, the amount of slip, elastic properties of the rock, the state of stress before the event occurred, and frictional parameters of the rupture. The calculated tilt values are correlated and compared with the recorded data, and are found to be of the same order. Certain input parameters, such as the initial rupture point, are further constrained by varying them, during modelling, until the calculated and observed tilt values are approximately equal. From modelling, it can be concluded that the rupture point had to be closer to the location of the tiltmeters. In addition, possible locations acting as source areas for the observed aftertilt are determined. Further modelling still needs to be done to quantify the effects of the tunnel close to the tiltmeters and plastic deformation of the rock mass. Keywords high-resolution tilt data, Mponeng gold mine, M 2.2 seismic event, analytical modeling, numerical modeling, rupture plane.

Oct 1, 2013

By David Allen

Cable bolting is a relatively new strata reinforcement technique that has been used successfully in Australia and the United Kingdom. Jim Walter Resources, Inc. has examined the principles and can visualize its useful application in many areas, such as: a) Longwall pull-out areas, b) Roadway junctions, particularly those involving yield pillars, c) Rib reinforcement, and d) Possible replacement of cribbing in roadways, especially longwall tailgates. This paper describes the conditions which led to cable bolt testing, the results of tests conducted to date, and conclusions about the direction that Jim Walter Resources, Inc. is heading as far as testing and potential applications are concerned.

Jan 1, 1994

Some low grade South Australian iron ores were classified on the basis of their physical characteristics. Ores from Mount Christie and Billeroo are coarse grained mixed ores; Mount Christie ore could be concentrated by gravity or dry magnetic separation at 10 mesh, but Billeroo ore needed to be crushed minus 36 mesh. Ores from Razorback Ridge and Wilgena Hill are fine grained mixed ores; ore from Wilgena Hill could be concentrated by flotation, but poor results were obtained on Razorback Ridge ore. Malcolm Creek ore is non-magnetic and crystalline, and can be concentrated by flotation, but the deposit is small. Ores from Grants Quarries and Peeralilla Hill are nonmagnetic and earthy and could not be satisfactorily concentrated.INTRODUCTIONThe Geological Survey of South Australia has for several years been undertaking a systematic study of the iron ore resources of the State (excluding the Middleback Ranges) in relation to their geology, reserves, and beneficiation. As part of the latter phase of the investigation samples of the ores have been submitted to The Australian Mineral Development Laboratories (AMDL), and it was the study of these samples which provided the material for this paper.The mineragraphic and metallurgical work was undertaken by several officers of AMDL and the results are contained in unpublished reports submitted to the South Australian Department of Mines. Field data published here was obtained from unpublished reports by G. F. Whitten, Senior Geologist, Iron Exploration, of the Geological Survey of South Australia.

Jan 1, 1964

By Yi Luo, Jian Yang, Hua Jiang

Surface subsidence events induced by underground longwall coal mining operations can cause various disturbances to surface structures ranging from integrity and stability to functionality problems. Highway bridges, as a kind of special road construction that can only tolerate smaller movements and deformations than road pavements, are particularly susceptible to severe influence caused by subsidence-induced ground movements and deformations. However, based on accurate subsidence prediction and correct influence assessments, efficient and effective mitigation and remediation measures can be designed and implemented to ensure the continuous service of bridges, safety of the travelers and smooth mining operations. In this paper, based on the predicted final and dynamic surface movements and deformations, the techniques to assess subsidence influence on the integrity, stability and functionality of bridge structures (e.g., decks, beams, abutments, etc.) are presented. A number of mitigation measures to protect the bridge structures are recommended along with an actual application case.