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By J. E. Urosek

Decisions made during a response to a mine fire or an explosion greatly affect the final outcome. The safety of miners should be the primary concern with accounting for all of the miners the first issue for resolution. If miners have not safely evacuated from the mine, the last known location of the miners at the time of the event and anticipated travel routes are primary exploration areas. After the mine is evacuated, there are many very important decisions that must be made quickly and often under great stress. It is critical that the mine operator establish an orderly method to direct the mine emergency response. Designation of a Command Center, staffed with personnel charged with developing plans, is a common method of establishing control. Scheduling of key mine managers will be critical, since decisions must be made 24 hours a day and people working for extended periods with little or no sleep do not always make clear or cognizant decisions. Internal communications, passing information on to subsequent shifts, and external communications with families and media must be accurate and timely. Assembling resources for responding to the mine emergency is critical for an effective response, and pre-planning can pave the way to a successful recovery. Sampling mine gasses and accurately determining the composition of gas mixtures is a common tool used to develop response plans in all fires and explosions. It is essential that preparations for emergency situations are made well in advance of a disaster. Effective communications are essential for mine management to successfully respond to a mine emergency. This paper discusses some considerations which need to be addressed in directing a response to a mine fire or explosion.

Jan 1, 2009

By J. F. Stiehr, R. L. Sanford, T. L. Myers

This paper summarizes the development of a Directory of Computer Programs Applicable to US Mining Practices and Problems. The directory is funded by the US Bureau of Mines and includes a sampling of computer usage in operating and manufacturing companies, consulting firms, computer companies, research organizations, universities, and various US government agencies. General references to computer applications throughout the mining industry are discussed as well as the availability of programs to interested organizations or individuals.

Jan 9, 1979

By C Placzek, E Beattie, K Blake

Channel iron deposits (CID) consist of ferruginous chemical sediments, and are an unusual subset of Phanerozoic ooidal ironstone deposits almost unique to the Pilbara, where they constitute around 19 per cent of the Pilbara’s iron ore exports. These deposits occupy many of the ancestral river channels of the Pilbara region, especially the Robe River palaeochannels, incising and meandering through the Precambrian banded iron formations (BIF) of the Hamersley Group and the underlying Fortescue Volcanics.This paper explores the factors underlying geochemical variation in CID, particularly the chemical properties of goethite. The selected deposits in the western Robe palaeochannel and its tributaries show little or no secondary reworking by later water tables. There is a total absence of aluminosilicate clays with all the deleterious elements such as aluminium and silica. Instead, these are associated with the goethite mineral lattice, either within or adsorbed to the cortices of pelletoids.A thickly vegetated environment, and the presence of the Maddina Volcanics as potential source rocks for these western Robe CID is offered as an explanation for relatively high aluminium in the deposits studied, and, in turn, as the reason most parts of the palaeochannel are preserved as inverted topography.CITATION:Beattie, E, Placzek, C and Blake, K, 2017. Dirty goethite – a geochemical characterisation of some western Robe River channel iron deposits, in Proceedings Iron Ore 2017, pp 489–502 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By D. S. Kieffer

Ground characterized by hard boulders embedded in soft matrix represents one of the most challenging conditions for TBMs, as the cutterhead must cope with the non-optimal conditions of cutting hard blocks while simultaneously excavating through soft, soil-like matrix material. Dowden and Robinson (2001) and Hunt and Mazhar (2004) summarize several case histories relating to the problems of advancing a TBM through boulder-laden ground and provide guidance with respect to appropriate site investigations and baselining strategies. Some rock types constituting boulder-laden ground include: ?Sedimentary Rocks?cemented alluvial channel deposits, colluvium/talus, landslide debris, and glacial till. ?Igneous Rocks?agglomerates, lahars, and pyroclastic deposits. ?Metamorphic Rocks?tectonic mélange and cataclastic fault zones. ?Decomposed Rocks?corestone bearing saprolites. Disc cutters are commonly utilized to cut the hardblocks; however, as compared to the understanding of disc cutter behavior in hard continuous rocks, little is known regarding fundamental cutting mechanisms in highly heterogeneous bouldery ground conditions. To advance this understanding, a suite of full scale tests have been performed using a linear cutting machine at the Colorado School of Mines (CSM). This paper summarizes the observed cutting mechanisms and their practical implications for TBM excavations through boulder-laden ground.

Jan 1, 2008

By M. Z. A. Bakar

A series of full scale laboratory linear rock cutting tests was carried out with a long bladed single disc cutter (292 mm diameter, 11mm wide constant cross-section blade) on dry and water saturated sandstone blocks using a linear rock cutting machine (LRCM). The muck collected from the cutting tests has been analyzed to establish a link with the specific energy (SE) of the operation. Coarseness index (CI), a non dimensional parameter, has been found to be a useful indicator of the relative efficiency of the cutting operation. An inverse relationship of the form SE = k CI-n is observed between SE and CI with very high CI usually corresponding with the lowest values of SE. The power n of the relationship for both dry and saturated rock tests is much less than the values found in the previous studies using constant cross section disc cutters and is believed to be dependent on the strength of the rock and the cutter type used. Although the average CI is found to be lower for saturated rock than for dry rock, at the same time saturated rock cutting is found to be less energy intensive (in terms of SE) than dry rock cutting. Moderate correlation exists between the production rate or yield and the SE of the cutting operation for both dry and saturated rock, which can provide some useful information about the field production rate discounting the effect of discontinuities in the rock mass.

Jan 1, 2012

By R. L. Zick, J. D. Byars, T. P. Mucho

Recently, a large Pittsburgh seam longwall mine was nearing depletion of a major portion of its current reserves and had begun to develop in a different direction from its original portal area to access additional reserves. This meant that a large area of the mine would be abandoned and sealed. However, continued use of the original mine portal area required that the water accumulating in the abandoned mine would eventually need to be pumped to the surface. This would be in addition to the discharge water associated with the new portion of the mine. Several pumping and sump options were investigated to handle the quantity and quality of the anticipated discharge water. This paper describes some of these options, their advantages and disadvantages, and the final engineering decisions. Some problems and unanticipated outcomes, as well as the eventual solutions are discussed, including: (1) estimates of pump requirements, (2) water pool size, (3) eventual water quality, (4) anticipated inflows, and (5) integration into the overall mine water system.

This publication is provided on an "as is" basis without warranties of any kind, either expressed or implied including, but not limited to warranties of title or implied warranties of merchantability of fitness for a particular purpose. The information contained in this publication is for general information purposes only. It does not constitute professional, technical, financial or other advice to the user of this publication and must not be relied upon as such by any person whatsoever. The use of this publication is at the users own risk. The authors/creators of the information contained in this publication have tried to ensure that the information contained herein is correct, but errors or inaccuracies may exist or the information may be incomplete, unreliable or no longer up to date. Therefore, no warranties of any nature whatsoever are given and any liability to any person in respect of anything and in respect of the consequences of anything done or omitted to be done, wholly or partly in reliance upon the whole or any part hereof, are disclaimed, including and without limitation any contractual, dialectal, direct, consequential or financial damages or losses. On no account will Organisers and/or any of the contributors or any person or entity involved in creating, producing or distributing the information and or software available in this publication be liable for any such damages arising out of the use of or inability to use this publication. Copyright Reserved The South African Institute of Mining and Metallurgy P O Box 61127, Marshalltown 2107, South Africa www.saimm.co.za All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical photocopying, recording or otherwise without the written permission of the copyright owner. Although the greatest care has been taken in the compilation of the entire contents, the editors and publishers do not accept responsibility for errors or omissions. First Edition Copyright February 2004 Proceedings ISBN: 0-9584663-5-1 (1 volume and CD-ROM)

Jan 1, 2004

The equity market is now very much within a global village environ- ment, with various exchanges acting as agencies for the big casino. In this predicament, mining companies, who provide the most extensive, but relevant risk assessment information, will be best placed for favoured treatment by potential international investors: But what risk assessment information in summary form can be provided to support a resource/reserve statement? Even more importantly, does "objective" data exist, whose trends will support a resource/reserve state- ment? A prime need of the informed mining investor is to determine whether or not the resource/reserve statement is believable? But more importantly will it be realised? While the implications within the text of the majority of reports on resource/reserves suggests that the estimates are conservative, the record indicates that very few estimates are. In fact, to date, reports claiming to be conservative in respect of the overall grade estimate at a specfic cutoff have not reflected the realised grade at the stated cutoff; it has been more common for the realised grade to be lower than implied by the resource/reserve statement. Further, it is not uncommon for penalty elements to be understated and these components are rarely incorporated within resource/reserve statements.

Jan 1, 1988

By Saeed Salehi Malekshah

In hybrid foundation system or piled raft foundation (PRF), the raft has adequate bearing capacity and piles are usually required to ensure overall stability of foundation and also to act as settlement reducer for high rise structures. When piles are connected to the raft, a high axial stress may develop and one alternative is to disconnect the piles from raft and consider them as stiffeners for supporting soil. This system is known as disconnected piled raft foundation (DCPRF). Cushion, a compacted coarse grained soil layer, can be used beneath the raft to redistribute and adjust the stress ratio of piles to subsoil and plays an important role in mobilizing the bearing capacity of subsoil and modifying the load transfer mechanism of piles. In this study, finite element method (FEM) has been employed to investigate the effect of different parameters such as cushion stiffness, gap height, raft thickness and piling configuration on the behavior of disconnected piled raft foundation. The analysis is performed on different foundations of hypothetical and real case histories. Results indicate that increasing the raft thickness reduces the differential settlement and pile head axial stress. Concentrating the longer disconnected piles similar to connected ones beneath the central area of raft, decreases settlement of raft. With increasing cushion stiffness, vertical stress ratio of piles to subsoil increases, but settlement decreases. Increasing gap height from 0.1 m to 1 m decreases the vertical stress ratio of piles to subsoil.

Jan 1, 2011

By H. K. Taylor, B. Denby, L. D. Smith

Contributions by H.K. Taylor and G.A. Davis discuss the three papers published in Transactions IMM A, vols. 103 and 104, with responses by Smith and Dowd

Dec 1, 1995

By L. D. Smith

"This paper examines the impact of the various assumptions that go into an economic evaluation, and shows how these can be combined to show an exciting result that may not really exist. An example of an embellished case (the kind that one frequently sees when projects are being promoted) is developed and the cumulative impact is analyzed to show the actual project underneath. The paper also points out some areas to watch for overly optimistic assumptions such as prices, inflation, and debt. The concept of a “bare bones” base case is proposed (constant metal prices, constant dollars, no inflation, no debt, no interest, on a project basis, after tax) as a common reference point.As well, the discount rate is examined as one of the fundamental means of reflecting risk in discounted cash flow evaluations. Current industry practice is discussed, and a methodology for the analysis of risk levels is proposed that assesses the constituent components of the discount rate: real interest, mineral project risks, and country risk."

Jan 1, 2002

While SME is hosting its Annual Meeting at the Phoenix Convention Center, Feb. 28 to March 3, one of the finest collections of mining history will be on display just 15 blocks away at the Arizona Mining and Mineral Museum. Inside the museum, visitors will be treated to a treasure trove of minerals, gems, me¬teorites, rocks, fossils, mining artifacts, historical exhibits and interactive displays on modern mining. The museum is located at 1502 West Washington. For SME Annual Meeting attendees, this is a free, eight-minute Dash bus ride 15 blocks west of the Phoenix Convention Center.

Jan 1, 2010

By Sherwin F. Kelly

THAT gold ores occur in Georgia is a fact apparently not widely known outside of that state, yet in the last hundred years nearly $18,000,000 worth of gold has been mined there. The discovery of gold-hearing quartz was made in 1823 on the "Forty Acre Lot" (which now belongs to the Columbia Mining Co.), in McDuffie County, and about seven years later the first stamp mill on record was erected near there. In recent years Georgia's gold production has dwindled to an insignificant figure. However, with the increase in gold price, interest in this district has been revived, so an electrical geophysical survey was undertaken to aid in discovering new quartz veins, on a part of the Forty Acre Lot, the adjoining Hamilton mine, and the nearby Woodall property.

Jan 1, 1934

By J E. Lynch

The Weda Bay nickel and cobalt laterite deposits on Halmahera Island, Republic of Indonesia were first drilled in May 1996 by Strand Minerals Pte Ltd (Strand). Subsequent exploration has delineated four large laterite provinces, parts of which have been diamond drilled to outline an indicated nickel resource of 59.9 Mt of 1.51 per cent Ni and 0.09 per cent Co within a total indicated and inferred resource of 117 Mt of 1.36 per cent Ni and 0.12 per cent Co. The project is held as a Seventh Generation Contract of Work (COW) by PT Weda Bay Nickel, which is jointly owned by Strand (90 per cent) and PT Aneka Tambang (ten per cent). Strand is a wholly owned subsidiary of Weda Bay Minerals Inc, a company listed on the Toronto and Alberta Stock Exchanges in Canada. Halmahera is located in the north-eastern part of the Indonesian archipelago at the convergent junction of three major plates and is a region of considerable tectonic and geological complexity. The western arms of Halmahera form a classic volcanic island arc while the central region and eastern arms contain ophiolite complexes and interlayered sediments. The extensive areas of laterite discovered at Weda Bay have developed over serpentinised harzburgites and dunites of pre-Cretaceous age. Weathering of these rocks has produced laterite profiles that are enriched in nickel and cobalt. There are three economically mineralised laterite types, namely limonites, ferruginous saprolites and saprolites and all are amenable to rapid pressure acid leaching with recoveries of 98 per cent nickel and 94 per cent cobalt in less than 20 minutes.

Jan 1, 1999

By E. J. Berentsen

The Turquoise Ridge gold deposit is located near the Getchell Mine, 72 km (42 miles)northeast of Winnemucca, NV (Fig. 1). The deposit is owned by Getchell Gold Corp. The host rocks consist of Ordovician and Cambrian age shales and limestones. They have been crosscut by the northeast-trending Turquoise Ridge shear zone and northwest-trending shear zones. Gold mineralization occurs at depths from 427 to 671 m (1,400to 2,200 ft) along the intersection of these structures. Large tonnage, flat-lying deposits occur where folded, favorable beds are intersected by the faults. The carbonate in the beds has been replaced with silica, pyrite and arsenic sulfides.

Jan 1, 1996

By Kri Inwood

"IntroductionIn 1879, when the Dominion government initiated its controversial program of industrial promotion, iron smelting in Canada was limited to one company producing coke iron on the mainland of Nov a Scotia and three small charcoal blast furnaces in Quebec. There was no steel production. By the eve of the first great war, iron and steel were being produced in very large quantities, the companies active in 1879 had disappeared and new centres of integrated iron and rolled steel production at Hamilton, Sydney and Sault Ste. Marie had come to resemble the industry as we know it today.The most dramatic change was that at Sydney, Nova Scotia, where in the early 1900s, two steelmaking companies established works. The Sydney developments have been explained as the result of resource discovery and technical change. W.J. Donald, in his authoritative account of the Canadian iron and steel industry, observes:""The most rapid growth of the Canadian iron and steel industry has occured since 1897... The remarkable growth has been caused largely by the new conditions of the industry. The discovery and use of Newfoundland ores, together with the availability of Cape Breton coal, has made the Nova Scotia industry not only possible but profitable ... It is a safe conclusion that the Canadian industry would not have been an important one, had it not been for the discovery of the Michipicoten and especially the Wabana (Newfoundland) ores""Donald also argues that metallurgical progress had been necessary to render the ores valuable,""Newfoundland ores ... contain a considerable amount of phosphorus, and were made available for steel-making by recent inventions.""The purpose of this paper is to re-examine Donald's story. It will be argued that the origin of steel -making at Sydney is somewhat more complicated than Donald has indicated. The difficulty with Newfoundland ore extended beyond its phosphorus content and a resolution required more than the basic open hearth furnace identified by Donald. Moreover metallurgical change was only one of several developments necessary to induce industrial investment at Sydney. Surprisingly, however, the discovery of iron ore in the late nineteenth century does not appear to be part of the explanation."

Jan 1, 1983

By D. A. MacFadyen, J. J. Brummer, C. C. Pegg

"The first record of a kimberlite found in Canada (1946) was the identification of thin dykes intersected while drilling for gold in Michaud Township, Ontario.Sampling of the Munro Esker (1964) in the Kirkland Lake area, Ontario, by the Geological Survey of Canada identified the occurrence of detrital grains of pyrope garnets along a length of 35 km of the 113 km tested. A search for the source of the garnets resulted in the identification (1968) of a narrow subsurface kimberlite dyke in the Upper Canada Mine. This discovery resulted in a staking rush. Unfortunately, subsequent work did not identify the source of the kimberlite indicator minerals.During 1978 the Ontario Geological Survey started a multi-discipline study of 29 townships (2560 krn2) in the Kirkland Lake area, to encourage exploration for gold, base metals, and kimberlites. Back-hoe sampling (1979 to 1982), where the overburden was thin, and reverse circulation drilling, in areas of thicker drift, yielded samples of the till. These were analyzed for several elements and a mineralogical identification of the heavy minerals was completed. Pyrope and chrome diopside grains were identified.Studies of the Pleistocene geology indicated only the most recent direction (167 degrees) of ice advance (Matheson) and the associated deposits, out of a possible three advances known to occur in the general region straddling the Ontario-Quebec boundary, is present in the immediate area of Kirkland Lake. Contouring the distribution of pyrope grains (1990) showed a concentration centered over an area of 616 km2 extending down-ice from Gauthier Township. This included a smaller area containing chrome diopside grains. Kimberlite boulders were identified (1981) in gravel pits on the Munro and Misema River Eskers located within this anomalous area. The next step would be to use the airborne geophysical data to locate the kimberlite pipes which yielded the indicator minerals and boulders. The source area is likely to be in the northern half of the Ontario Geological Survey study area."

Jan 1, 1992

In late 1989, first-pass reconnaissance exploration delineated a 4km x 6km geochem- ically anomalous area centred 10km WNW of Kainantu in the Eastern Highlands Province at 6¦13'S and 145047'E. The area, named the Basangka prospect, lies between 2 200 and 2 400m asl. Interest in the area was prompted by a 14ppm Au assay of a silica-pyrite breccia float sample taken near Henkai village. The prospect was defined after several acid-leached silica- pyrite breccia and comb textured quartz float samples returned assays above lppm Au and relatively high Ag. Very encouraging and anomalous Au values were obtained from panned concentrates, despite the absence of visible Au colours. Several pan concentrates returned greater than 1mg Au and it is believed that the Au occurs as inclusions within iron oxides which were originally pyrite. In this early stage of prospect exploration, any Au value above 0.lppm in- 150# fraction stream sediments is treated as anomalous. Rock chips, panned concentrates and -150# fraction geochemistry all vividly define the areas of interest at Basangka.

Jan 1, 1991

By Susan P. Taite, Alain R. Charest, Peter D. Lewis

The El Sauzal deposit is a classic, high sulfidation, epithermal gold system located in the southwestern Chihuahua state of Mexico (Fig. 1). A Francisco Gold geologist discovered the prospect in1995. El Sauzal was encountered as a result of an extensive grassroots exploration program in the rugged, dissected volcanic terrains of the Sierra Madre Occidental, around the historical Batopilas silver camp. At El Sauzal, high grade gold is hosted within a series of more permeable, low-dipping, lithic and fine-grained dacitic rocks of early Tertiaryage. The mineralization appears tobe structurally and lithologically controlled. The alteration characteristics are typical of a high sulfidation system, including kaolinite, illite, alunite, dickite and pyrophyllite.

Jan 1, 2005

By Burns W. G, Muceniekas E, Whitcher I. G, Hughes F. E

No iron ore deposits were reported before 1961 from the Hamersley Ranges, Western Australia, although low-grade bedded iron formations, associated with ferruginous jaspers and cherts, were known to occur in the local Nullagine Series of Precambrian age.In January-March 1961 preliminary investigations in the area drained by the Turner River, Duck Creek and Serpentine Creek revealed the presence of over 1000 million tons of dense botryoidal or pisolitic limonite, forming flat-lying orebodies with 50-57 per cent iron.Large bedded hematitic orebodies were also discovered in the same area in August-October 1961. These have a porous, biscuity texture and an iron content of 60-61 per cent. They occur at a welldefined stratigraphic level (Brockman Iron Formation), normally in synclines where they have been upgraded by circulating meteoric waters during an old cycle erosion.In 1962 systematic geological studies and mapping, together with sampling and scout drilling, indicated larger reserves of biscuity hematitic ore and led to the discovery of massive hematite deposits at Mt. Tom Price. These were extensively drilled in 1963, proving the persistence of' high-grade mineralisation to a depth of 200 ft and over.To date the total indicated reserves of the Hamersley deposits, within the area held by Hamersley Iron Pty. Limited, are of the order of 4960 million tons and thus rank among the more important of the world. The reserves are composed of 600 million tons of bedded dense hematite ore with 64-66 per cent iron, 2900 million tons of bedded biscuity hematite-limonite with 60-61 per cent iron, 1360 million tons of limonite (goethite) ranging in grade from 50 to 57 per cent, and 100 million tons of canga (conglomerate) iron ore containing 53-63 per cent iron. In all cases harmful impurities are comparatively low.

Jan 1, 1964