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By Peter J. Huck, Swpan Bhattacharya, Madan M. Singh

This paper reviews the state-of -the-art techniques for estimating the duration of post- mining subsidence arising from different mining techniques and evaluates existing post-mining liability systems in the United States and abroad. For each mining technique (room-and-pillar and longwall) the mechanism of subsidence development is examined and the critical factors influencing the duration of subsidence are evaluated. These are followed by a comprehensive summary of field data on the duration of subsidence movements collected in various parts of the world. Using this information, graphical charts are developed to depict the relationship between the time duration and critical controlling factors. Also included are any mathematical relationships that may exist between the different variables. Finally, a survey of current state, federal and foreign legislation on mine operator liability time spans is provided. These laws are evaluated for their applicability in light of the data on duration of residual subsidence. On the basis of this evaluation, guidelines are suggested for the establishment of the mine operator liability structure for the United States.

Jan 1, 1986

The papers in this section of the conference and indeed the conference as a whole will rightly focus on the recent û the state of play around the Pacific Rim. However, to set the scene I propose to take a longer-term perspective. In so doing I wish to illustrate and emphasise that change is normal and natural û to paraphrase Bob DylanÆs 1963 classic, æThe times they are (always) a-changinÆ Æ. The challenge is how to cope with such change, in an industry, a corporate and a personal sense. A further challenge for geologists, both exploration and mine-based, and indeed for anyone, is to understand where they fit in the broader picture. For several reasons it is appropriate first to look briefly at the minerals industry in the Pacific Rim around a century ago. It was here in Adelaide in April 1893 that the first general meeting of the Australasian Institute of Mining Engineers (or The Australasian Institute of Mining and Metallurgy as it later became) took place and where the Centenary Meeting was held in 1993. The late 1800s and early 1900s was a period of extraordinary change in the minerals industry regionally and worldwide. The industry benefited from the economies of scale provided by improved mechanisation. It further benefited from the introduction of technically qualified professionals, such as chemists, metallurgists and mining engineers, although the usefulness of geologists had yet to be recognised commercially. With the rise of such professionals, technical societies formed and flourished. At the same time international financial markets and trade were expanding, a gold standard was widely supported and the financing of mining ventures was well established. Mining was an international business and its people travelled widely. As a consequence of the better-educated mining professional, the ready exchange of knowledge and the availability of finance, new processing techniques such as pyritic smelting, the cyanide process and flotation were developed. These, together with much improved materials handling in the mining and processing phases, dramatically changed the economics of the minerals industry.

Jan 1, 2004

By Neil Williams

The brecciated dolostone-hosted (Mississippi Valley-type) and associated shale-hosted stratiform Pb-Zn deposits at McArthur River occur adjacent to a major syndepositional fault, the Emu fault. Base-metal zoning, mineral parageneses, and Pb and stable isotope ratios indicate that both types of deposits formed contemporaneously from metalliferous brines that flowed into the host sediments from the Emu fault. Derivation of brines from underlying evaporitic sediments is suggested. Geochemical evidence indicates that the mechanism of ore formation was sulfate-reduction coupled with oxidation of organic matter. The textural relationships of stratiform sulfide mineralization to diagenetic dolomite concretions, chert blebs, volcanic glass shards, and inter-ore breccia beds, indicate that the reactions proceeded diagenetically within about 100 m of the sediment/water interface.

Jan 1, 1979

By C. R. Breck

THERE has been a running discussion over the-past several years with respect to the life and adequacy of our natural gas reserves.. Some of the experts agree on one phase of the subject at least--that eventually it will be necessary to augment deliveries of natural gas in the northern markets by the development of a more or less comparable synthetic gas made from coal. The purpose of this paper is to point out: 1. It may be later than a good many people think-the demand for additional domestic and commercial pipeline gas in at least one section of the North will probably be felt rather keenly before an adequate synthetic pipeline-gas project, developed on economic lines, could be completed, even if ' initiated in the near future. 2. The evidence is considerable that such a project would be technically sound and economically self-supporting, although the margin of profit at first might be so small and the magnitude of an economic enterprise so great that financing would be impossible without Government aid in some form or other. The part of the country referred to is the heavily populated section in the northeast of the United States. To simplify an examination of the situation, let us take the potential marketing areas within range to the north and east of the three pipelines: 1. Tennessee Gas Transmission Co. as it enters Erie County, New York state. 2. Texas Eastern Transmission Corporation just before the tap that supplies the general Philadelphia area. 3. Transcontinental G& Pipe Line Corporation as it enters the state of New Jersey The sources of gas for these three pipelines are in Texas and Louisiana. The ultimate maximum combined capacity of the three lines at the points stated is approximately 1,200,000,000 cu ft per 24 hr at the maximum load factor probable of attainment in normal operation. The areas supplied by the three lines north and east of the points stated, or assumed as eventual markets, are: 1. Central New York state, from Buffalo to Albany (both inclusive).

Jan 1, 1953

"THE GOLD MINING REGION of Timmins - Val d'Or, astride the Ontario-Quebec border, has long suffered the effects of rising costs during the period when the U.S. price of gold was fixed at $35 per ounce. The federal government, through such assistance programs as that set up under the Emergency Gold Mining Assistance Act (E.G.M.A. ) in 1948, has subsidized the gold mining communities of Canada for a total of over $300 million to March 31, 1972. Of this, the Timmins - Val d'Or ""gold belt"" has received more than twothirds, almost $220 million. In spite of these continuous subsidies, only 12 gold mines are still producing in the Timmins - Val d'Or belt, whereas 71 mines have received subsidies for some period since 1948. The vital question is how the communities previously supported principally by the mining of gold will survive in the long run, as many of the older mines either are already depleted or are quickly becoming so. With the rising price of gold on the 'free market in recent months, prospects look a little brighter for the time being. Even with the increased official price of U.S. $38, which made the maximum government subsidized price about $48 per ounce, gold mines have not sold any gold to the government since January 1972 and some stopped doing so months before that. The populace of the region has not been enthusiastic about relocation nor about extensive retraining programs in the past and probably will not be in the future. So, when the remaining gold mines become depleted, the old problems of community depression will remain."

Jan 1, 1973

By William R. Rumbold

THE Kinta valley in the State of Perak, one of the largest of the Federated Malay States, is probably at the present time the richest alluvial tin-district in the world, Perak producing from 20,000 to 25,000 tons of tin annually, and the Kiuta valley being the chief producer. The valley runs approximately north and south, and is 30 miles long by 12 wide. It is very flat, the mountain-ranges on either side rising abruptly from the plain, that on the east being the great Central range of the peninsula, and that on the west a subsidiary range marked " Kledang " on the map, Fig. 1. The valley is drained by the Kinta river, which rises in the eastern mountain range and flows south to join the Perak river, being joined by numerous streams from both mountain-ranges. The rain-fall is heavy, averaging annually about 90 in. The whole country is covered with dense jungle, except where it has been cleared for mining-operations and a small amount of cultivation. Mining villages are scattered throughout the valley, the chief towns being Kampar, Batu Gajah, Lahat and Ipoh, the latter being the center of the mining-operations. An ideal section of the main geological features of the Kinta valley is given in Fig. 2. The valley is composed of a highly crystalline limestone, usually white in color, sometimes gray; in fact, it may be called marble. It is always highly inclined and often contorted, and in some places is interbedded with shale. On the east side of the valley, near its contact with the granite, it forms a remarkable series of limestone cliffs, which rise in some cases as high as 2,000 ft. above the level of the limestone in the valley. It is non-fossiliferous, and its geo-

Sep 1, 1906

By Clyde Sitterud

Presentation Agenda ?Global Mining Tire Demand ?What is driving it? ?Latest Situation ?How long it will last? ?Michelin?s Response to Increase Supply ?New plant ?Additional presses ?Recommendations for Mining Users ?Treat tires as your major assets ?Areas of attention that will produce immediate results

Jan 1, 2005

By Joseph T. Singewald

The term "titaniferous magnetite" is used to designate those magnetic ores of iron that carry more than 2 or 3 per cent of titanium. Large and easily workable deposits of these ores occur in different parts of the world, and have attracted attention for many years. Under present furnace practice, however, the smelting of these ores is both difficult and expensive, and for that reason they are not accepted by furnaces, so that the deposits are practically worthless. The problem of finding a feasible method of utilizing these ores has naturally been attractive, and numerous attempts have been made to solve it. Experiments to that end embrace two lines of investigation. The one that has been the more frequently tried is the elimination of the titanium from the ores, so as to make possible their smelting in the usual way. The other is the devising of a method of smelting by which titaniferous ores may be reduced as economically as are non-titaniferous ores. The former method involves a physical process, the latter a chemical process.

Jan 1, 1913

By Frank J. Markewicz

The expanding: demand for ilmenite for use in the manufacture of titanium pigments, the knowledge that much of this raw material comes from distant points and therefore has to include a heavy freight charge in the price of the delivered product, and the further knowledge that ilmenite occurs both in the crystalline rocks of northern New Jersey and also in some of the Triassic igneous rocks, were considerations which led to a search for ilmenite-bearing sands in southern New Jersey. That this search was successful is now history, and it is the senior author's privilege to state here that most of the credit belongs to his associates who did all of the heavy work of hand-augering for samples, and who made all of the heavy-mineral separations. We all are grateful to members of the Department of Geology at Rutgers and Princeton Universities for the use of equipment which enabled us to evaluate certain samples from our ilmenite exploration program. In addition, we wish to express our appreciation to many companies for their cooperation and for their permission to publish mineral and chemical analyses. We also acknowledge with much appreciation our debt to the geologists and engineers with whom we have had many lively and rewarding discussions relative to the ilmenite deposits.

Jan 1, 1958

By Caress ME, Knight MD

The eruption 75,000 y ago of the Younger Toba Tuff ignimbrite and associated ash-fall ranks as the greatest known volcanic event of the past million years. The ignimbrite is known to cover 21,000 km2 (it may extend farther under alluvium of the coastal plain) and forms a low-angle depositional shield centered on the Lake Toba caldera. The ignimbrite is largely nonwelded and shows systematic outward decreases in lithic and crystal contents and clast sizes. Coarse lithic lag breccias that occur at places 85 km apart point to two or more vents on a fissure having this length. The extensive associated ash-fall traceable as far as Malaysia and India is evidently a co-ignimbrite ash but could have a phreatomag-matic component. The Lake Toba caldera measures95 x 35 km and is >1 kn deep. It is not a single caldera but comprises several contiguous depressions and grabens diversified by two re-surgent domes. Earlier parts of the caldera are related to at least two earlier ignimbrites including the Older Toba Tuff dated by Chesner at 0.5 Ma. The caldera is elongated parallel to, and is only 25 km from, the great Sumatra strike-slip fault, and it can be considered almost certain that the caldera is in part a kind of pull-apart structure. The ignimbrites are very crystal-rich. There is no reason to think basaltic magma was involved in their emplacement. Together with ash-falls they have a total volume of several thousand cubic kilometers. They can be categorized as originating from partially crystallized granitic magmas that erupted because tectonic pull-apart occurred several times across the pluton. Small rhyolitic lava domes on fault-lines comprise the youngest volcanic products.

Jan 1, 1990

By M. K. Senicie

IN July, 1937, Asbestos Corporation, Limited, installed an automatic conveyor-belt scale at their King mine, Thetford Mines. The equipment was purchased 'on trial' and its performance has proved entirely satisfactory to the staff. The scale was manufactured by the Toledo Scale Company, of Toledo (Ohio) and Windsor (Ont.) and was installed by one of the Scale Company's engineers. The electrical recording equipment was installed by Keith Mercer, Reg'd, of Montreal, Canadian agents for the manufacturers, the Builders Iron Foundry, of Providence, Rhode Island. The recording equipment consists of a duplex weight-transmitter attached to the scale-head, a duplex totalizer with differential relays, a belt-speed compensator, a rate-of-delivery recorder, and a rate-of-delivery indicator. As it was desired to run the mill at maximum capacity, it was necessary to know the rate of feed at all times, so that any lessening of rate of feed or delays would be recorded and could be corrected. After having determined the rate of feed to the mill (100 per cent capacity), it was required to have weighing and recording instruments which would show: (1) The rate of feed per hour. (2) Any variations .in the load. (3) Any delays and the duration and time of the delays. Rate of tonnage recorders in the mill superintendent's office and at the point of feedi.ng were necessary, as was automatic control between the mill superintendent and the feed man. It was desired to have a permanent record of total tonnage fed per shift or day; weighing and recording mechanism had to have sensitivity to record all previously mentioned conditions. Mechanism had to be of rugged construction, and be so built that it would stay in good operating condition, with the minimum amount of adjustment and supervision.

Jan 1, 1938

By Robert W. Bruhn

The prediction of damage to a structure that is to be undermined is generally a two step process. First, the expected ground movements (the displacements, slopes, curvatures, and strains) are estimated using available (often empirical) predictive methods or survey data from a site of comparable geology, topography, and mining geometry. Second, the prospects for damage to the structure are assessed by comparing the expected ground movements to tolerable limits, some of which appear in the technical literature as damage criteria. The inverse problem of relating observed building damage to causative ground movements involves essentially the same elements. In either case, the usefulness of published damage criteria to subsidence problems may be limited in all but the most elementary cases. This paper considers several cases where structural behavior and site specific details had to be taken into account in assessing the relationship between damage and ground movements.

Jan 1, 1986

By G J. Corbett, T M. Leach

A continued exploration programme has further defined the geology of the Tolukuma vein system, verified the resource indicated by Newmont, and identified potential for additional mineralisation. The resource at Tolukuma Hill, designated as zone C, is a mine recoverable 432,000 t at 18.1 g/t Au & 46 g/t Ag. Mining will be by a combination of open pit and underground at a rate of 100,000 t per annum. Processing will be by SAG mill, gravity circuit and CIL plant. A diatreme breccia, localised at an intersection of structures and a relationship of gold to base metal sulphides, are indicative of a strong porphyry association. Typical epithermal features such as crustiform banded quartz and quartz pseudomorphing platy calcite are also present and locally contain lesser gold mineralisation. Pre-existing dilatant structures have acted as a host to the ore fluids, resulting in the formation of the semi-continuous Tolukuma-Gulbadi veins over a 1100 m strike. A fluid flow model suggests that mineralizing fluids were sourced from a diatreme margin and migrated laterally along dilatant structures. Bonanza gold grades are interpreted to be derived through fluid quenching in the flexure between a hanging wall split, which hosts much of the Tolukuma Hill resource, and the feeder graben structure. Thus, the relationship between the pre-mineral structural geometry and fluid upflow at the margins of a diatreme breccia, controls the ore setting.

Jan 1, 1995

By M S. Reston

The Tonkolili banded iron formations (BIF), Sierra Leone, host extensive iron ore deposits which are of economic signifi cance to the seaborne iron ore trade. The deposits are dominated by a strategic JORC compliant mineral resource of 11.6 Bt grading 30.1 per cent Fe comprised of primary magnetite mineralisation in the form of a fresh metamorphosed BIF featuring a uniform mineral assemblage of quartz-magnetite ± ferro-silicate minerals. Pilot plant metallurgical test work has demonstrated that the production of a magnetite concentrate is achievable using the established beneficiation techniques of magnetic separation and flotation. The concentrates arehigh-grade, and suitable for blast furnace or direct reduced iron pellet feed. The major challenge facing the development of such magnetite deposits at industry competitive production rates is the significant capital investment required for process plant and associated infrastructure.Two well-developed weathering zones exist within the deposits, and are associated with the progressive development of a tropical weathering profile overprinting the primary BIF. These zones feature a near surface hard indurated duricrust up to 60 m thick, and a soft progressively developed saprolite between duricrust and fresh BIF. These zones have been found to be amenable to producing iron ore products including DSO lump and sinter fines from the duricrust, and concentrate from the saprolite. Mineral resources sufficient to support commercial production of such iron ore products were defined by an intensive exploration program in 2010.African Minerals Limited has developed a three phase production strategy to progressively self fund the development of the Tonkolili strategic magnetite project by:• commencing a Phase I 12 Mt/a DSO operation in Quarter 4 2011,• increasing production in Phase II to 35 Mt/a with the commissioning of a saprolite beneficitation plant and associated infrastructure upgrades, and• developing a 45 Mt/a Phase III operation producing high-grade magnetite concentrate.The comparatively low capital and operating costs of a duricrust DSO lump and sinter fines operation coupled with its proximity to ground surface make it highly attractive for the generation of early cash flow for the Tonkolili project. Revenue from this early production may be used to selffund the subsequent development of phases requiring progressively more significant beneficiation plant and infrastructure.

Jul 11, 2011

By A. H. Jones

(San Francisco Meeting, September, 1915). THE Belmont mill at Tonopah, Nev., was designed and constructed by the Belmont staff. Ground was broken in August, 1911, and milling operation started July 25, 1912. The metallurgical flow sheet, and the machinery adapted to carrying out operations in accordance with this plan, were decided upon from experience gained in the treatment of Belmont mine ores at the old Belmont mill at Millers, Nev. The detail drawings were made by the-engineering staff of the Tonopah-Belmont Development Co., under the supervision of Otto Wartenweiler, who also .had direct charge of the construction, consulting with the General Superintendent of the company, Frederick Bradshaw, and the writer.

Jan 8, 1915

By H. N. Thomson

GENERAL. THE Tooele plant of the International Smelting & Refining Co. is situated at the mouth of Pine canyon, Tooele county, Utah. It is connected with the main line of the San Pedro, Los Angeles & Salt Lake railroad by the Tooele Valley railway, and is about 7 miles from Tooele Junction. Fig. 1 is a general view of the plant. FIG. 1.-TOOELE PLANT OF THE INTERNATIONAL SMELTING & REFINING Co. The copper plant has been in operation since July, 1910, and the first blast furnace at the lead plant was blown in on Feb. 29, 1912. The location of the plant was selected on sloping ground with the idea of using gravity to the fullest extent and thus keeping labor at a minimum. Practically the entire plant is constructed of steel, reinforced concrete, and brick. Bingham ores, both lead and copper, are received over the Utah Consolidated Aerial Tramway. The tram buckets, each containing

Jan 7, 1913

By H. N. Thomson

(Butte Meeting, August, 1913.) GENERAL. THE Tooele plant. off the International Smelting & Refining Co. is situated at the mouth of Pine canyon, Tooele county, Utah. It is connected with the main line of the San Pedro, Los Angeles & Salt Lake railroad by the Tooele Valley. railway, and is about 7 miles from Tooele Junction. Fig,. 1 is a general view of the plant. The copper plant has been in operation since July, 1910, and the first blast furnace it the lead plant was blown in on Feb. 29, 1912. The location of the plant was selected on sloping ground with the idea of using gravity to the fullest extent and thus keeping labor at a minimum. Practically the entire plant is constructed of steel, reinforced concrete, and. brick.

Jan 7, 1913

By B A. Wake, G G. Lowder, M J. White

The Tooloom gold field is located within the New England Fold Belt in the far northeast of New South Wales, approximately 130 km south southwest of Brisbane. Gold was first discovered at Tooloom in 1857. Within a few years up to 10 000 people were mining placer gold deposits in the Tooloom valley and a few tried their hand at mining hard rock occurrences as well. Mining of alluvial gold continued in a small way at Tooloom until very recently, but only in the last few years, since Malachite Resources acquired its interest at Tooloom (now 100 per cent), has the full potential of this large, reduced intrusion-related gold field been appreciated. By the mid 1870s, once the alluvials were largely worked out, most of the early miners had made the 270 km trek north to the newly discovered Gympie gold field and Tooloom slipped into obscurity. Such was this obscurity that the Tooloom gold field was not recorded on published Government geological maps until 2001, four years after Malachite became involved. The many hard rock prospects that Malachite has identified in recent years were largely or completely unknown. Tooloom is a good example of blinkered thinking when it comes to modern mineral exploration. The New England province in NSW has long been the æpoor relationÆ to the much better known and more highly favoured Lachlan Fold Belt in NSW. It has also suffered serious neglect compared with the Queensland part of the New England Fold Belt that hosts such major gold deposits as Mt Morgan (>7 Moz), Gympie (>3 Moz) and Cracow (>1 Moz). Tooloom is proof that prospective geology does not stop at state borders.

Jan 1, 2004

By C. A. Rowland

With the rapidly rising cost for electrical energy and the long range pre¬dictions for continued rising costs and even possible energy shortages, operation of rod, ball, autogenous and partial autogenous grinding circuits to efficiently utilize the power delivered to the mills will be demanded. This calls for a method to evaluate grinding circuit performance that is accurate, reliable and readily usable as an operating tool by supervisory, technical and operating personnel. Neither the Rittinger and Kick theories of comminution,(1) which preceded the Bond Theory by more than 50 years, had a mathematical means that could be used to predict and evaluate the performance of crushers and grinding mills used to comminute ores and rocks. This severly limited the practical use of these two theories, which were contradictory to each other. They have been superseded by the Bond Third Theory of Commnution.(1)

Jan 1, 1976

By L MacDonald, D Molver, D Pepper

Increasing contamination/impurity levels (including arsenic, antimony, mercury etc.) of concentrates is an issue of global commercial and health / environmental significance. With increasing environmental pressures at smelters, penalties for contaminants in concentrates continue to rise, accompanied by lower reject limits. There is a strong incentive for miners to investigate alternative means to remove contaminants in order to increase the value of complex ores and concentrates. This paper discusses the global problem of contamination in complex ores and concentrates, how the Toowong Process technology is a potential solution to this problem, and the opportunities this technology brings to the business of dealing with deleterious elements. CITATION: MacDonald, L, Molver, D and Pepper, D, 2018. The Toowong process for treatment of complex ores, in Proceedings Complex Orebodies Conference 2018, pp 119–121 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018