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By E Werner, B R. Leavitt

The chemistry of acidic mine drainage discharging from flooded coal mines is commonly reported to improve with time after flooding. This investigation describes a 18-year dataset of post-flooding water chemistry for a below-drainage underground coal mine within the northern Pittsburgh coal basin (Pennsylvania, USA). The Montour mine is a 5650-hectare below-drainage coal mine of maximum 260 metres depth. Montour was closed in 1980 and flooded to within 38 metres of land surface within 4.8 years. Pumping averaging 210 L/s was then employed to maintain water levels at this elevation. The flooded proportion of the mine (by volume) at full flooding was 56 per cent. The shaft where water was pumped from Montour for water control is located about 70 per cent of the distance between the mine water table and the back of the mine ù that is, it is close to the back of the mine. The residence time (total water volume at flooding divided by pumping rate for control) is estimated at 5.6 years. Time series of chemical analyses show three phases of chemical behavior in post-flooding discharge. In Phase I (zero to two years after flooding), iron concentrations were high and reached their maximum (1100 mg/L). In Phase II (two to four years after flooding), a transition was begun to alkaline conditions, with decline in iron and other solutes. In Phase III (>4 years), net alkaline conditions began, with iron concentrations declining exponentially to 50 per cent of mined volume. This attainment of net alkalinity in this case may have also depended on abundant calcite in overburden extended up to 30 m above the mine floor.

Jan 1, 2003

In Australia 'there are hidden deposits of gold, copper, tin, lead and zinc which can be found by drilling at reasonable expense in view of the imp9rtance of the objectives. Exploration of the prospects in mind would mean about a million feet of drilling. The purpose of this paper is to outline, in a technical way, some of the geological thinking that has been given to this matter. To do this, it is necessary to unify the wider ranging thoughts into some sort of coherent perspective and also into some sort of logical sequence. This will be done by treating first the geological subject material which is in fact, at the foundation of the exploratory scheme. With this base, the argument will be continued through a sequence of prospect thinking and brought to a conclusion in regard to the practical employment of geology in the drilling planning. In this knitting together of ideas, the discussion will be given substance by welding into the argument the reasoning that has been applied to the Cobar prospect. The New Occidental Gold-Mines are operating three mines at Cobar, and the writer is indebted to the Company for allowing the reference to be made. It is intended, as opportunity permits, to furnish further examples in later publications.FOUNDATION OF EXPLORATIONThe deposits under consideration are derived from igneous rocks, chiefly granite or porphyry. In and following the emplacement of the intrusives, the rocks have been...

Jan 1, 1946

The karst water system in Han-Xing District is charaterised by heterogeneity in karstification and permeability of the limestone aquifer, unsteady flowing of the groundwater along karst runoff zone system, periodic recharge related with the periodic precipitation, and concentrative discharge of the groundwater in the form of karstic spring groups. The basic law is that the quantity of the water is very large during waterflood period and rather small in dry period, which has brought about difficulties and contradictions in mining and water supply. The measure to bring the karst water under control must be based on the principle of comprehensive ways and on the systems engineering method. Macroscopiclly, it is the reasonable countermeasure to retain surface water in the upstream section of the karst water system and to strengthen infiltration in the midstream section and to combine exploitation and utilization of the groundwater with water protection and mine dewatering in the area in which mines are distributed.

Jan 1, 1988

By W Dodson

Major ions, d18O and d2H and Carbon-13 concentrations in groundwater from 30 bores near an open pit iron ore mine were used to better understand the chemical evolution of groundwater in the aquifer. The relatively depleted d18O and d2H isotopes of groundwater from various depths suggest that groundwater is recharged from intense rainfall events, with little evaporative effect. The 300 to 500 mg/L increase of major ions relative to that of rainfall is due to evapotranspiration of rainfall during recharge. Geochemical mass balance modelling suggests that the evapotranspiration of rainfall during infiltration through the unsaturated zone varies over six fold from 20 to 130. This coupled with the dissolution of CO2 from the unsaturated zone and partial dissolution of carbonates and gypsum from Tertiary sediments and carbonates from the Wittenoom Formation accounts for the current major ion, d18O and d2H distribution in groundwater. Despite the relatively dissected morphology and steep hydraulic gradient the results of this study highlight the dominance of vertical flow relative to horizontal flow. The study also shows the dominance of rapid recharge by significant rainfall events as an important component of the water budget for east Pilbara aquifers.

Jan 1, 2009

In North-West Nelson the Riwaka Complex, a linear basic intrusive complex, is exposed for approximately 45 kilometres. Some 500 kilometres south, across the Alpine Fault, a linear zone of similar but less well known basic intrusives that may be correlatives of the Riwaka Complex is exposed discontinuously for about 80 kilometres. The Complex was emplaced at several centers along a major tensional fracture zone that developed in upper Carboniferous to Lower Permian time. This fracture zone probably formed in response to the development of a west dipping subduction zone that gave rise to the Permian volcanic arcs in east Nelson and western Southland. The Riwaka Complex contains three rock suites. The Fractionation Suite, characterized by cyclic mineral layering and small scale cumulus banding is the largest and is divided into the Ultramafic, Hornblende and Plagioclase Series, each of which is subdivided into several units. The Cumulus Gabbros represent a restricted but important suite of unusual composition, while the third suite is the late phase Diorite Suite.

Jan 1, 1980

The discovery of copper and nickel sulphides in the Riwaka Complex in 1967 led to considerable exploration activity by a number of companies. Various exploration techniques used by these companies are summarised and discussed. Activity of these companies shows that mineralisation is mainly confined to the southern, ultramafic section of the Riwaka Complex where geological mapping recognised sixteen units within, or associated with the Riwaka Complex. Significant pyrrhotite, pentlandite chalcopyrite mineralisation is restricted to biotite feldspar pyroxenites and to clinopyroxenite units. Lesser and more erratically distributed pyrite chalcopyrite pyrrhotite mineralisation occurs in poikilitic pyroxene hornblendites, melanocratic gabbros, and in marginal diorite lenses. It is suggested that a linear belt of layered ultramafic and mafic rocks described in Fiordland by Williams (1974) may be a southern extension of the Riwaka Complex. The Riwaka Complex has been classified as belonging to the Picritic subtype, (Tholeiitic suite), of Naldrett and Cabri, (1976), and as such it is concluded that it exhibits substantial potential for the discovery of economic copper and nickel deposits. It is considered that the complex is a multiphase differentiated intrusion emplaced in a major tensional fracture zone that developed in a relatively stable tectonic environment, namely a succession of middle Paleozoic shallow water shelf sediments. Based on sparse available evidence it is suggested that the Riwaka Complex was intruded in the lower to middle Permian. It is further suggested that the tensional fracturing was initiated by the onset of subduction process which were responsible for the development of the Permian volcanic arcs and ophiolite belt in the north west Nelson area.

Jan 1, 1977

By Dobos K

The Clermont Goldfield, from which about 300,000 oz of bullion have been extracted, was one of the major gold producers in Queensland. This paper is derived from a systematic study of the mineralogy, geochemistry, and stable isotope geochemistry of the deposit, based on detailed field work and logging of 57 reverse-circulation percussion drilling holes at the Black Ridge Gold Deposit (Fig 1), aimed at addressing the long debated question of gold-ore genesis at Clermont, i.e., whether it is of fossil placer or hydrothermal origin.Detailed petrologic and mineralogical studies indicate the hydrothermal alteration at Black Ridge is dominated by extensive siderite (+rhodochrosite-ankerite) veinlets and stockworks, which are concentrated along the deformed unconformity between the Anakie Metamorphics and basal conglomerates of the early Permian Blair Athol Coal Measures. Siderite alteration is also moderately developed in all other rock units represented at Black Ridge, including the Tertiary basalt. Weak to moderate phyllosilicate alteration is common throughout the deposit, including chlorite-sericite along the shear zone of the unconformity, and sericite-clay in the conglomerates. A sulphide-oxides zonation also has occurred, including pyrite below the unconformity, (pyrite)-chalcopyrite-marcasite-(hematite) along the deformed unconformity, and marcasite (hematite, pyrite) in the conglomerates.

Jan 1, 1990

By Woodcock JT

Successful chemical control of flotation requires practical solutions to many problems. A brief discussion is first given of those para- meters which can be controlled and those which it would be desirable to control. Suitable analytical methods for application to flowing pulp and to clear solution from pulp are out- lined in relation to on-line and off-line control. Practical problems of deciding where a measurement is to be made or a sample is to be taken and how the sample is to be prepared and presented to the measuring device are then considered. Equipment calibration and maintenance are considered in relation to the above factors.

Jan 1, 1978

Mineral resource classification is essential because it is required for public disclosure. The resources must be binned by a qualified person into measured, indicated and inferred categories using an appropriate methodology. The classification methodologies used have long been a topic of research and discussion. There are various traditional and geostatistical methods used in practice. Some are more popular than others. Because of the uniqueness of each ore deposit, it seems almost impossible to have a single industry-accepted norm for mineral resource classification. Therefore, some experts have adapted the methodologies tailored for the deposits they are working on, but many simply use the methods they and their clients understand and are comfortable with. In this paper, a new approach is presented to classify the mineral resources using a data geometry index. This index combines both traditional and geostatistical aspects of resource classification based on the data configuration around the block interpolated. It is a function of several variables such as kriging variance calculated for a block, distance from the block to the nearest sample and the average distance of all samples used to interpolate the block. Thus the approach using this index takes into account the spatial data configuration around the block being estimated, as well as the traditional distance criteria. The data geometry index and how it is calculated is explained. A case study for a gold deposit is presented to see how the classification based on this index compares to the existing methodology used in this deposit for mineral resource classification.

Sep 26, 2011

THE exceptional rainfall characteristic of the West Coast of Tasmania, in conjunction with the rugged topography of the district, has always suggested the utilization of water-power, and from the earliest days of the Mount Lyell Company theeventual installation of a hydro-electric power scheme, making use of some near-lying lake, has constantly been kept in view. At the period of the inception of the company, however, the time was not ripe for such an undertaking, and it is only oflate that the various important considerations involved have sanctioned incun;ing the heavy expenditure necessary, with the positive assurance of permanently reaping the benefits expected. The West Coast of Tasmania contains many lakes of varioussites; situated at high levels, and, although the catchments of these lakes are not very extensive, still, the excessive rainfall is so constant over long periods that its regularity may be relied on as offsetting the limited catchments. The explanation of the abnormal rainfall is simply the circumstance that the West Coast Range forms the first high land barrier which is met by the moisture-laden westerly and north-westerly winds blowing off the Southern Ocean. By the time the clouds strike the mountains they ride very low, consequently the elevation of the range, the peaks of which do not exceed 3000 to 4000 ft. above the sea, is sufficient to cause a copious precipitation. Lake Margaret, which is situated five miles north of the reduction works, was first recognized as a possible source of waterpower by Mr. Hugh Ohrisp, a surveyor, who visited it about 1893-4. Earlyl in 1895, while the preliminary work on the erection of the first furnaces of the Mount Lyell Co.'s reduction...

Jan 1, 1915

By Cowie WJ, Utting BS

The alluvial gold industry of New Zealand is based on the placer deposits in Otago and on the West Coast. Production from these since discovery in the 1850's has been an estimated 480 tonnes (15 million ounces) of gold. Annual output has expanded continuously since 1980 and is expected to be over 2 tonne of gold for 1989.Following a historical review, the characteristics of typical operations, which use hydraulic excavators and mobile trommel units are discussed. Descriptions are then given of alluvial activities in Otago and on the West Coast.

Jan 1, 1990

By Hinton A. T

Three, and possibly four, distinct types of quartz-vein associated gold mineralisation are recognised in New Zealand. They are: epithermal, schist-hosted, metagreywacke-hosted and metamorphic core complex associated types. Each has a unique geological environment and structural regime which has provided the gold source, scavenging mechanism, emplacing mechanism and geometry. Each has a characteristic suite of associated metals and trace elements. The first three types form economically important gold deposits while the fourth type have been historically worked for gold and base metals. Intense exploration is currently being focussed on all four types.The epithermal type is typified by the extensive vein systems of Martha Hill, Karangahake and Golden Cross and numerous smaller examples. The veins were deposited in a near surface active volcanic environment from deeply circulating hot water. Their structure is tensional, veins are vertical-to sub-vertical and have limited depth. Their geochemistry is identical to that in active felsic hydrothermal centres in the central North Island. Major minerals are gold, pyrite, arsenopyrite, galena, chalcopyrite, sphalerite and argentite.

Jan 1, 1990

By G H. Luttrell

The use of secondary desliming cyclones ahead of froth flotation cells to reject ultrafine (-45 ¦m) particles has become a popular option in the United States for preparing fine coal feeds for froth flotation circuits. In light of this popularity, several experimental studies have been performed at industrial plant sites to develop a better understanding of the impacts of ultrafine desliming on froth cell performance and, ultimately, overall plant performance. These studies included an evaluation of various circuit configurations incorporating different flotation technologies (conventional machines and column cells) as well as different dewatering systems (disc filters, screen-bowl centrifuges, and thermal dryers). The data obtained from these studies indicate that deslime circuits offer several important benefits including lower product ash, reduced product moisture, better froth handling characteristics, and lower capital and operating costs. In addition, case studies conducted as part of this investigation have been used to develop generic guidelines for how deslime circuits may be successfully applied to improve the overall profitability of fine coal flotation circuits for both the metallurgical and steam coal markets.

Jan 1, 2005

By Farrelly C. T

The Wiluna mining operations are centred near the township of Wiluna 750 kilometres north-east of Perth and 600 kilometres east of Geraldton.The Wiluna gold mines produced over two million ounces of gold, predominantly by roasting the refractory sulphide ores, before closing in 1947. In the period 1984 to 1992, 668 000 ounces of gold has been produced from free milling oxide ores and the retreatment of tailing. A plant capable of treating the refractory sulphide ores using the bacterial oxidation, Biox technique was commissioned in March, 1993.The Wiluna lode deposits are hosted by a sequence of very low grade metamorphosed mafic flows at the northern end of the Norseman-Wiluna greenstone belt. A strike slip fault system provided conduits for fluid migration; ore deposition occurred at favourable sites along the faults. Satellite mines at Gourdis and Wiluna South provide laterite and lode style oxide ores.The different styles of deposit and ore types at the Wiluna mining operations require a flexible approach to resource estimation and grade control practices.

Jan 1, 1993

By Payne AR

The high cost of gateroad repairs and maintenance in U.K. longwall coalmining is a clear indication of the failure of permanent support systems to fulfill their prime function, i.e. control of strata movement. The main component of gateroad support is the pack, the design and materials of which have experienced an important development process during the last 10-15 years. More recently, research investigators have attempted to give a design basis to pack quality and dimension, and reference is made to two theoretical approaches. In the course of a current research programme based upon in situ monitoring, interim design recommendations have been proposed as a means of effecting improvement in support efficiency. Identification of characteristic deformation behaviour forms the basis of the recommendations made and the subsequent improvement in gateroad performance reported.

Jan 1, 1986

By Borgelt B. V, Perry A. J, Wellington H. K

There has been little change in the lead smelting practice at Mount Isa since 1939 when the metallurgy and general practice were outline by Raney and Blott.The purpose of this paper is to descriqe some of the operational details that have influenced the overall production. The slag fall hns been increased by the lowering of the lead content of the concentrate. Further, as it is the practice to include iron on the furnace charge and carry a higher lime content in the slag, both factors have produced notable results in furnace operations.All blast furnace gases are filtered in a baghouse and this unit is. being further extended to take all smelter gases, thus eliminating the existing Cottrell plant handling Dwight-Lloyd gases.The lead smelter was closed down from April 1943, to May 1946, during which time blister copper was produced.The report is subdivided as follows:-1. Filtering and Mixinga. Effect of calcium sulphate on cloth.b. Dwight-Lloyd charge composition.c. Main mixer.d. Return sintel sizing.2. Blast Furnace Operationsa. Introduction.b. Use of orehearth.

Jan 1, 1953

By Trevits MA

The United States Steel Corp. in cooperation with the United States Government is conducting a large-scale methane drainage field demonstration using stimulated vertical boreholes drilled in advance of mining. A grid pattern of 23 boreholes, isolating approximately 1.5 km2 of coalbed area, has been drilled to the lower bench of the Mary Lee coalbed, Jefferson County, Alabama. Upon completion of drilling operations, various hydraulic stimulation treatments utilizing nitrogen-generated foam, water, and gelled fluid were performed to enhance the rate of methane gas removal. Production from the grid pattern began in September 1977 and continued as the last borehole was placed on production during October 1980. To date, in excess of 33,800,000 m3 of methane gas has been drained as a result of this effort. Underground mining operations were approximately 3.2 km from the grid pattern when production began and have currently progressed to within 1.6 km. Underground interception of the grid is expected in 1986.

Jan 1, 1982

By Munro DL

The Mary Kathleen uranium deposit is in north-west Queensland, approximately halfway between the townships of Mount Isa and Cloncurry, at long. 1400 009 E and lat. 200 44' S. The deposit Iwas discovered by prospectors of the Walton McConachy Syndicate early in July, 1954, and climaxed a very intensive ground search by hundreds of part-time prospectors. during the uranium boom from March to July 1954ò Numerous small deposits, mostly in the vicinity of Mount Isa, were discovered in various rock environments, but Mary Kathleen is the only large deposit and, apart from a few tons of hand sorted material from the Milo lease, is the only deposit that has been worked. Exploration of the surrounding area, and proving of the economic worth of the deposit, were conducted from the time of discovery until February 1956 by a geological team camped near the deposit. Proving was carried out by drilling a pattern of vertical and inclined diamond drillholes at fifty-foot centres over the outcrop. An adit was driven eastwards through the deposit. Metallurgical research and design work in the South Australian Department of Mines Adelaide Laboratories were based on core samples and bulk samples from the deposit. The signing of a contract in March 1956 with the British Atomic Energy Authority to supply 4500 short tons of uranium oxide allowed mining to commence, and enabled the planned construction of water supply, township and treatment plant to proceed. The open out mine and plant are now serviced by a modern township, four miles away, which is connected to Cloncurry and Mount Isa by road. Although little field work has been done since the exploration phase, this paper differs in interpretation from a previous paper (Matheson and Searl, 1956) in that it is based on a revised structural inter- pretation (Compana, 1958), detailed mapping of progressive exposures in the open out, and a re-examination of diamond drill cores.\

Jan 1, 1968

Coal is of tremendous importance for the Czechoslovak econ- omy. The current annual primary energy demand being about 109 million tons of standard fuel (1 ton of standard fuel - 7,000 coal = 29,308 GJ), coal satisfies almost two thirds of our fuel consumption. If compared with the distribution of resources in the world's fuel and energy pattern, the situation in Czechos- lovakia is significantly different, as shown in Fig. I. One of the causes behind the difference is that the Czechoslo- vak oil and natural gas reserves and, hence, their production are insignificant, so that it is necessary to import them. Brown coal will continue to play an important role as a prin- cipal domestic source of primary energy even in the future. While the share of nuclear power is increasing, brown coal represents strategic reserves in the fuel and energy balance.

Jan 1, 1989

By Elford H. S, Hughes J. F

The object of this paper is to bring before Members of the lnstitute the very important and much discussed question of scientifically prospecting for ores, oil, coal, etc.The paper is divided into three sections:SECTION l - Description of Geophysical Prospecting methods.(1) Sound-Vibration.(2) Magnetic.(3) Gravitometric.(4) Electrical.(a) Equipotential.(b) Electro-magnetic.(c) Schlumberger.(d) General.SECTION II - General discussion of Cicophysical Prospecting.SECTION III - Appendices.(1) Systematic summary of methods of survey.(2) Table of electrical conductivities.(3) Bibliography.SECTION I - DESCRIPTION O:F GEOPHYSICAL PROSPECTING METHODS.(1) SOUND-VIBRATION.THE transmission of sound waves or vibrations underground will depend on at least three factors: (a) Type of Rock. - Hard, dense rocks wiII transmit sound waves much more quickly than softer, more porous rocks. In the former the speed may be eight times that of the latter.(2) Uniformity of Rock. - Any variation in the texture, hardness, etc, wiII have an effect on and direction of transmission of the waves.

Jan 1, 1927