Search Documents

By J C. Volkwein, A D. A Hansen, E Sarver, C Barrett

Ensuring that diesel particulate matter (DPM) levels in underground metal and non-metal mines are maintained below statutory limits is an essential requirement of mine ventilation systems. However, despite the cost of providing ventilation, air ventilation rates are usually based upon models, assumptions, or measurements integrated over long durations rather than actual need. Real-time measurement of DPM, interpreted in terms of mine activity schedules, can offer better ventilation management to keep DPM within regulated levels while controlling costs. This work presents data from three demonstration sites with in-mine applications of an environmental particulate sensor that measured black carbon (BC) as a surrogate for DPM.Aethalometers are a class of environmental monitors that measure the light absorbance of aerosol particles at several optical wavelengths. A model AE33 Aethalometer was operated in three separate mines for periods of two weeks, three months, and seven-plus months, and the data was reported in real time as a concentration of BC. Concentration of aromatic organic compounds, which can indicate other forms of combustion, was also reported. The data was used to:- measure the relative efficiency of a new scale-model DPM air scrubber- determine if ventilation could be reduced in a shotcrete loading facility without compromising air quality- evaluate diurnal and weekly DPM levels in a large-entry stone mine. Instrument data were displayed locally and stored for later downloading in all cases. In one mine, the instrument was connected to a local controller, and in another it was connected to the mine’s underground network so that DPM data was presented in real time to a display in the mine ventilation engineering office on the surface.The results showed that the air scrubber removes from 82 per cent to 95 per cent of the DPM; that DPM produced during shotcrete loading is only a minor part of overall DPM levels; and that wide variations in DPM levels exist in the limestone operation. The DPM monitor operated continuously for extended periods in these underground environments. The only maintenance required was the routine replacement of filter tape, typically on a two-week schedule. A sample diluter, which is currently being tested, could extend the intervals between filter changes. The real-time data output of the Aethalometer is appropriate for direct integration into ventilation-on-demand control systems.CITATION:Volkwein, J C, Barrett, C, Sarver, E and Hansen, A D A, 2017. Application of an environmental ‘black carbon’ particulate sensor for continuous measurement of DPM in three underground mines, in Proceedings Australian Mine Vent Conference 2017, pp 143–150 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By Jena Moshen

Underground Bulk Systems (UBS) technology has gained widespread application in tunneling and underground mining owing to its safety, reliability, increased Velocity of Detonation (VOD) and excellent results. However, its application in perimeter blasting is still limited and researchers are looking at ways of harnessing this technology for perimeter control. This simplifies the charging process by using one cost efficient product for charging both the perimeter and grid holes. This paper presents a case study on the application of underground bulk emulsion explosives for perimeter control blasting in underground room and pillar platinum mines. In order to achieve the required coupling ratios in the perimeter holes, the emulsion is loaded into specially formulated smaller diameter polyethylene (poly) pipes. The effectiveness of this method was evaluated using information obtained during routine blast audits and data supplied by the mines on half cast factors, over break and under break as well as analysis of data from Ground Penetrating Radar (GPR) Scans over a period of four years. This method of perimeter control, has given the platinum miners in Zimbabwe a competitive edge in cost effective perimeter charging and blasting by simplifying the previously costly deployment of traditional barrels and other decoupled cartridges. The method has been adopted by all the platinum mines in Zimbabwe as it has proven to be a cost effective alternative of controlling the perimeter walls, along with other key benefits that relate to safety, productivity and effectiveness.

Jan 1, 2018

Except for uranium search, conventional oil well logging techniques are relatively little-used in mining exploration. The main reasons for this are cost and an apparent lack of awareness of the potential use of the methods in the search for ore. However, relatively inexpensive portable units are currently available for performing the simpler electrical and radiometric logs in diamond drill holes.The emphasis in oil exploration logging programmes is largely on the estimation of porosity. In most mineral work, however, porosity is not very significant, and factors such as mineral conductivity and radioactivity assume an important role.The Bureau of Mineral Resources (BMR) during a programme to explore for uranium and associated base metals in the area east of Rum Jungle, N.T., carried out electrical and radiometric logging of diamond drill holes as a routine part of their investigations. Case histories are described in which the logs were used to aid in defining stratigraphic sequences and transgressive structures in base-metal prospects. Some surface geophysicalanomalies were explained by the logging: induced polarization and electromagnetic anomalies were related to black slate; and self-potential anomalies were related to oxidation of pyrite black slate, or apparent electrokineticeffects in the black slate. The logs provided an objective appraisal of the rock units penetrated and thereby helped to differentiate lithologies.Borehole logging, including newer techniques such as downhole analysis, could be done in geological and geophysical investigations in other areas for a relatively small cost with a considerable potential gain of information.

Jan 1, 1978

By B. B. Broms

Embankment piles are common in the Scandinavian countries (Kjellman, 1940) and in Southeast Asia as support of fills, light structures, bridge abutments and deep excavations (Eide, 1968) as described in the following. Untreated timber piles are often used for light structures and shallow fills when the ground water level is high since they are inexpensive and readily available. When the applied loads are relatively high precast concrete piles and steel piles are preferred. DESIGN CONSIDERATIONS Embankment piles carry the load from a fill or a struc-ture either through skin friction along the sides of the piles (Fig. 1a) or through a precast concrete slab or through pile caps at the top of the piles (Fig. 1b). When the load is carried by skin friction it is often economical to use small diameter timber piles because of the large surface area (Asplund, 1939). For precast concrete or steel piles concrete caps are used to transfer the load to the piles due to the relatively high capacity of the piles since the skin friction resistance alone is not sufficient to transfer the load to the piles.

Jan 1, 2010

By O. K. Mahabadi

The scope of this study is to simulate the behaviour of a layered rock sample under standard laboratory Brazilian Disc test using an innovative combined finite-discrete element method (FEM/DEM) research code. The influence of layering and the direction of loading on the samples behaviour are studied through various layering and loading configurations. A parametric study including the effect of loading rate on the tensile strength of samples has been carried out. This paper demonstrates the suitability of the numerical approach to explicitly model rock deformation and failure.

May 1, 2009

Studies of the Main Seam in the Rapahoe Sector of Greymouth Coalfield have shown that the proportions of palynomorphs and palynomorph groups vary vertically within the seam, but remain laterally consistent. Subsequent examinations of other seams in the Rapahoe Sector have demonstrated that the changes in palynomorph proportions observed in the Main Seam are specific to that seam, effectively providing a seam 'fingerprint'. Such a characteristic signature may be used to identify the Main Seam where faulting or seam splitting confuses seam correlation between drillhole intersections. Palynomorph assemblages are derived from the original plants which formed the peat mire, and yield information on mire conditions such as climate, mineral matter input and chemistry. These depositional factors influence coal properties such as mineral content, volatile matter yields and coal breakability. Palynological data can therefore assist in development of depositional lTIodels for prediction of coal quality variations. Several other, thiner seams in the Rapahoe Sector have been demonstrated to also contain recognisable palynomorph assemblages, suggesting that other seams may also possess distinct palynomorph abundance profiles.

Jan 1, 1996

By Nick Barton

When the Q-system was launched in 1974, the name referred to rock mass classification, with focus on tunnel and cavern support selection. Besides empirical design of support, the Q-value, or its normalized value Qc, has been found to correlate with seismic P-wave velocity, with deformation modulus, and with deformation. The Q-system provides temporary or permanent support for road, rail, and mine roadway tunnels and for caverns for various uses. It also gives relative cost and time for tunnel construction for a complete range of rock qualities. There are also indications that Q has captured important elements of the cohesive and frictional strength of rock masses, with Qc resembling the product of rock mass cohesion and rock mass friction coefficient.

Jan 5, 2007

By T de Wit, S Meyer

The location of seismic events in mines is traditionally calculated based on the arrival times of P- and S-waves for a given velocity model (homogeneous or heterogeneous). This technique is successful when the sources of seismic events are sudden and localised (eg episodes of fracturing in solid rock or dynamic slip along a plane of weakness) and thus the radiated seismic waves have clear arrivals. In massive mining operations such as block caves, strong seismic signals often originate from the movement of loose rocks on the perimeter of the fracture zone. These signals are easily recordable but do not contain easily identifiable direct P- and S-waves, making the estimation of location through traditional methods more complicated. This problem has been approached by using a ‘brightness’ location method that estimates the origin of seismic waves based on travel times of envelopes of seismic energy. This tool is extended to be applicable in a heterogeneous velocity environment that now accounts for the presence of a cave or other strong velocity perturbations. The suggested method is particularly important when caving occurs in low-stress environments (eg close to the surface).CITATION:Meyer, S and de Wit, T, 2016. Location of seismic events associated with caving using brightness method, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 225–236 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By K. P. Fournier

This report describes work on the problem of predicting oil recovery from a reservoir into which water is injected at a temperature higher than the reservoir temperature, taking into account effects of vis cosity-ratio reduction, heat loss and thermal expansion. It includes the derivation of the equations involved, the finite difference equations used to solve the partial differential equation which models the system, and the results obtained using the IBM 1620 and 7090-1401 computers. Figures and tables show present results of this study of recovery as a function of reservoir thickness and injection rate. For a possible reservoir hot water flood in which 1,000 BWPD at 250F are injected, an additional 5 per cent recovery of oil in place in a swept 1,000-ft-radius reservoir is predicted after injection of one pore volume of water. INTRODUCTION The problem of predicting oil recovery from the injection of hot water has been discussed by several researchers. l-6,19 In no case has the problem of predicting heat losses been rigorously incorporated into the recovery and displacement calculation problem. Willman et al. describe an approximate method of such treatment. 1 The calculation of heat losses in a reservoir and the corresponding temperature distribution while injecting a hot fluid has been attempted by several authors.7'8 In this report a method is presented to numerically predict the oil displacement by hot water in a radial system, taking into account the heat losses to adjacent strata, changes in viscosity ratio with temperature and the thermal-expansion effect for both oil and water. DERIVATION OF BASIC EQUATIONS We start with the familiar Buckley-Leverettg equation for a radial system:* This is sometimes referred to as the Lagrangian form of the displacement equation. If the injection water is at some temperature Ti which is above reservoir temperature TR, then lw, the flowing fraction which is water, is a function of both water saturation and fluid temperature at any given time and position in the reservoir. The temperature dependence of lw results from the temperature dependence of the viscosity ratio µo/µm of which lw is a function. Thus:

Jan 1, 1966

By E. H. Jr. Dix

THE use of magnesium as an alloying element in aluminum alloys has been limited, in general, to comparatively small quantities. In duralumin-type, strong-aluminum alloys, magnesium is present to the extent of ½ to ¾ per cent. and various grades of Magnalite and the "Y" alloy of the National Physical Laboratory of England contain up to 1 1/2 per cent. In this country small quantities of aluminum alloy sheet containing 4 per cent. magnesium are produced commercially. All commercial aluminum contains sufficient silicon to convert a portion of the magnesium added to the compound Mg2Si. It is well known that the solubility of both magnesium and magnesium-silicide decrease with decrease in temperature. It is, therefore, impossible to separate the age-hardening effect of the magnesium-silicide from that of magnesium, except by the use of aluminum of such high purity that the silicon content is negligible. The present paper is the fifth1, 2,3,4 of a series from the laboratories of the Aluminum Co. of America reporting the results of investigations of the equilibrium relations in aluminum-rich alloys made from the high purity aluminum manufactured by this company .5

Jan 1, 1929

Up to the end of World War n, flat-back cut and fill stoping with or without square sets was the universal method of ore extraction. Rapid changes in practice occurred during the post-war years; first, ore extraction was fully mechanized; secondly, the stope design for new levels, notably No. 17 Level Zinc Corporation Ltd. and No. 19 Level New Broken Hill Consolidated Ltd., was modified to suit this mechanization; and thirdly, sub-level and shrinkage stopes were developed in orebodies where cut and fill methods would be uneconomical. The following is a brief survey of the changes that have occurred-most of which were inaugurated during the last five years.ROCK DRILLINGDuring 1951 open stoping was investigated in detail. In order to reduce steel handling problems, forged steel onepass detachable bits were introduced, but were soon superseded by the "Swedish method". Investigation showed that when using a bar and arm mounted 3-in. drifter the overall drilling time was approximately 6 min. per ft. compared with 4 min. per ft. using the light jackhammer-airleg combination with 1-in. hex. by 4-in. collared shank tungsten carbide-tipped steel.Although competitive with tipped steels on a cost per foot drilled basis (excluding miner's time), detachable steel bits proved most unsatisfactory for hard drilling conditions.Rapid blunting necessitated frequent bit changes and thus caused lost drilling time. This, together with rapid gauge...

Jan 1, 1957

CONTENTSSummary.Introduction.Location and Geology.Historical and Exploitation.Part 1. Washability Characteristics of the Liddell.Seam.Foybrook Open Cut, Top Bench.Sampling.Size and Ash Distribution.Washability Data.Washery Separations.Part 2. Washability Characteristics of the LiddellSeam.Foybrook Open Cut, Bottom Bench.Sampling.Size and Ash Distribution.Washability Data.Washery Separations.Acknowledgments.References.INTRODUCTIONThe washability characteristics, size-range and chemical analyses of the screening from the Liddell Seam are matters of growing interest in view of the increased exploitation of this seam over the last few years, and also since the Newdell Coal preparation plant of the New South Wales Mining Company Proprietary Limited, utilizing magnetite heavy media separation, commenced...

Jan 1, 1954

The southern portion of the Swan Coastal Plain, a geomorphological element formed since late Tertiary times, contains commercially exploitable accumulations of ilmenite, zircon, rutile and monazite associated with a series of raised shorelines. The location of the deposits is controlled by a locally outcropping Archaen granite/ granulite complex and a sea current pattern determined by local geography and a prevailing wind direction. A progression from medium to high titanium ilmenite is evident parallelled by progressive leucoxenisation as the age of the deposits increases. Variations in trace element content accompany this process. Circulating groundwater has caused vertical mineralogical variations within individual deposits and by precipitation of iron has formed layers of hardpan.The Geographe Bay deposits are of important economic significance.INTRODUCTIONObservations made during the course of a brief survey of the southern portion of the Swan Coastal Plain provide an outline of the geology and mineralogy of the mineral sand deposits of the area. This preliminary study will require considerable modification in the light of more detailed work in the future.REGIONAL GEOLOGYThe Geographe Bay area is situated in the south-west corner of Western Australia between longitudes 115° O'W. and 116° O'W. and latitudes 33° 15'S. and 33° 45'S.The general geology of the area is shown in Fig. 1 where the control of the physiography exercised by the Cape Leeuwin-Cape Naturaliste basement ridge is readily apparent. Between this ridge and the Precambrian east of the Darling fault lies the southern part of the Perth basin which contains outcropping Jurassic to Recent sediments and lavas (McWhae, et al., 1958).The Leeuwin-Naturaliste ridge is the exposed portion of L Assistant Production Managcr. Laporte Titanium (Aust.) Ltd.

Jan 1, 1964

By Jerry Ran

Stope back caving in a mine using open stope mining interrupts the planned mining sequence and causes oversize muck and dilution with adverse economic implications. As many underground mines are mining or have plans to mine at depth, stope back caving could have significant impact on the mine sustainability. Therefore understanding the caving mechanism is important in preventing future occurrence and improving the mine economic performance. Falconbridge Ltd Kidd Mine is an underground mine using open stope method producing more than 2 million tonnes per year. Its current lowest mining level is approximately 2070m below surface and the lower portion of the orebody is being developed. In years of 2002 and 2003 the back of three stopes of approximately 1900m and 2040m below surface caved and caused substantial mining difficulties at the mine. As these caved stopes are subject to stress concentration, seismic activities and near major geological structures, the caving mechanism is much more complex than that of stopes near surface. In addition to the recorded caving history by site observations, the mine carried out cavity surveys and test drilling to define the caved profiles. The mine seismic monitoring database provided information at these stopes. Stress modeling work conducted by an external consultant provided the stress patterns at the caved stopes. Based on the field collected data and stress and seismic information, this paper presents details of the stope caving process and cavity surveyed profiles, reviews the predictability of the stability graph approach for these cases, discusses the caving mechanism and proposes preventive measures to stabilize the stope back.

May 1, 2004

After a five year period representing the strongest resource and commodity rally ever experienced, we are now faced with a subdued recovery following the global financial crisis. This renewed economic growth will be steady but eventually attain levels that reignite export demand out of China and other emerging nations, which are now reliant on increasing domestic demand to support their economies. This backdrop of weaker share prices and less available investment capital creates a greater imperative for company management to ensure that its share price is fully valued. The mining geologist plays an important role in achieving this outcome through direct estimation of asset value (resources) but also in strongly communicating the æupsideÆ value opportunity in both mine site and adjacent brownfields exploration and an efficient and technically sound mining operation. The contribution of mining geologists to assist in conducting analyst site visits should not be underestimated, particularly with reduced analyst coverage of the resources sector and some simplification in company analysis through ranking companies on Reserve and Resource positions.

Jan 1, 2009

By Robert Jakiel

The following paper is being presented to provide a basic understanding of the equipment and procedures used in multi-auger deep soil mixing as part of the program for the Deep Foundations Institute (DFI) Deep Soil Mix Seminar. The paper is written as a summary of the author's experience using multi-auger deep soil mixing equipment while working with SMW Seiko, Inc. on several east coast projects in the United States, particularly the soil-cement mixing for the soil stabilization of the Fort Point Channel area in Boston, Massachusetts, one of the largest and most difficult soil mixing projects completed thus far in the United States. The summary provides a brief summary and insight into some of the operational aspects of the equipment and procedures, and some of the important considerations when using multi-auger deep soil mixing. This paper is intended for use by both the contractor and the designer involved in selecting appropriate soil mixing equipment and procedures for various types of soils, depths or applications, or for a better understanding of the operational aspects, potential benefits, and impacts that the performance criteria may have on the operational capabilities of the soil mix equipment, when specifying multi-auger soil mixing for a particular project. Prior to reading this article it is important to become more familiar with the various acronyms and terminology used in soil mixing technology. A Definitions section has been provided at the end of the paper that will help the reader become more familiar with some of the terms used throughout this paper.

Jan 1, 2001

Geological hazards such as faulting, basement ridges, and zones of "thin" (< 6 m) coal have a major impact on mining economics of underground operations in Huntly Coalfield. Experience has shown that drillhole-based investigations do not yield sufficiently detailed models of the coal seam to allow management of the planning risks associated with these hazards. Consequently, operational performance is affected by unplanned costs associated with lower productivity, loss of coal reserves, and expensive strata control remedies in problem ground conditions. Huntly Coalfield is a challenging environment for acquisition of good quality seismic reflection data due to the very thick (10-85m) weathering layer. Since 1994, successful acquisition of 2D and 3D data has been achieved through a combination of careful testing of technical parameters and experimental trials prior to committing to production recording. High resolution seismic reflection (HRSR) is proving to be an investigations technique which generates accurate and reliable models of the coal seam and associated structures, such as normal faults and topography of the surface on which the coal seam rests. The HRSR technique has been applied and developed in the Okowhao Sector where Huntly East Mine is developing and extracting coal reserves. Results of a recent 3D survey demonstrate that this technique is capable of revolutionising risk management in mine planning for underground mines in structurally complicated coal deposits.

Jan 1, 1997

By J. M. Weehuizen

Complete details are given of the drilling method by which two shafts were sunk at the new Beatm'x mine of Staatsmijnen in the Netherlands. The nature of the rock strata in the Dutch mining district determined choice of the drilling rather than the freezing method. Data for each step and details of the equipment used are given in the illustrations. Staatsmijnen was founded in 1902 with government financial backing, but it is run as a private enterprise, on a commercial basis, with the normal fiscal obligations. The company now has four mines in operation with annual outputs amounting to 7 1/2 million tons of coal. In 1952 it was determined that a new mine—the Beatrix—would be opened. Details of the shaft-sinking operation are described in this paper. SHAFT LOCATION The coal-bearing carboniferous rock in the Dutch mining district is overlain almost completely by soft water-bearing strata, which at the site of the new shafts are about 1600 ft thick. The sinking of the new shafts through this soft water-bearing overburden (Fig. 1) is a costly and time-consuming affair. From the two availaible sinking methods: 1) Poetsch's well known freezing method or 2) the drilling method of Honigmann-de Vooys, the latter was preferred, not only because of its relative cheapness, under the prevailing conditions, but primarily because by using the drilling process, a special type of shaft lining of steel, concrete, and bitumen could be used. The new shafts, located 330 ft apart, have an inner diameter of 18 ft, 4 1/2 in. The boreholes, which have a diameter of 25 ft and which were drilled through nearly 1600 ft of overburden and some 100 ft of carboniferous, each contain more than 29,000 cu yd—by far the largest in the world. DRILLING METHOD The drilling method is based on the use of mud-flush—a thin mixture of clay and water—to keep the borehole filled during the entire drilling period and during insertion of the lining (Fig. 2). The pressure of the mudflush against the borehole wall is greater than that of the water in the surrounding

Jan 1, 1961

By M Wimmer

LKAB operates two underground iron ore mines located in the northern part of Sweden, both using sublevel caving (SLC) as the mining method. Knowledge of the mechanisms of gravity flow is important since it affects both ore recovery and waste dilution. This paper describes results from a large-scale field test carried out at the Kiruna mine with a focus on gravity flow. It is part of Work Package 2 in the I2Mine project financed by the EU. A total of ten rings were blasted. Smart Markers based on radio frequency identification technology were used to monitor the gravity flow. An accurate delineation of the isolated extraction zone requires reliable detection of all recovered Smart Markers and precise knowledge of the 3D position of the markers within the burden. It was therefore necessary to carry out borehole deviation measurements (collar, alignment and trajectory). The blast performance was monitored by high-speed filming, near-field vibration monitoring and velocity of detonation measurements. Three-dimensional stereo images were taken from the drawpoint and the loaded bucket after each mucking cycle. Based upon that, fragmentation was assessed both in 2D and 3D. Furthermore, volumetric differences were determined at the drawpoint, which reflects the mobility of loaded material. For draw control, the Fe content is estimated by measuring weight and assuming a full bucket. The measured volume of rock in each bucket further improves this estimate. Possible flow disturbances occurring at the drawpoint were revealed by video recording. Two-dimensional laser scanning was carried out during mucking to track the position of the bucket and estimate the position and slope of the muck pile.The results from this test clearly show that the gravity flow in the large-scale sublevel cave in Kiruna mine is often of disturbed character. Standard draw occurred only in three rings and shallow draw in the remaining seven rings. In five cases, shallow draw developed towards standard draw, but occurred at rather late stages during extraction (70–125 per cent). The maximum width of the draw varied between 10 m and 13 m except for one ring (6 m). The draw reaches the cave rather early (5–25 per cent extraction) in shallow draw situations and much later (about 50 per cent) during standard draw. Waste originates from above in most cases, while more significant portions often occur at about 20–45 per cent extraction.All the results from this extensive field test are not yet fully analysed, and further field tests are planned. A more detailed insight into gravity flow in large-scale SLC and possible influence by drilling, blasting and the mucking procedure is expected in the future.CITATION:Nordqvist, A and Wimmer, M, 2016. Holistic approach to study gravity flow at the Kiruna sublevel caving mine, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 401–414 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By E. T. Turkdogan

Jan 1, 1962