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By Peter M. Fozzard

A review is made of the actual costs of recent foreign mineral exploration programmes in third world countries. Target identification leading to the selection of areas, or macro-targets, must follow a well planned and defined series of steps. Suggestions are made with respect to this inter-active project development work. Potential revenues in the broad sense will always determine the overall economics of exploration but clear objective philosophy, good planning and adequate financing are essential for exploration success. Considerable opportunities exist for making important foreign mineral discoveries and broad selected suggestions are made for the identification of exploration areas in relation to high-grade and precious metal mineralization.

Jan 1, 1984

By R. Jacobson

This paper presents comparison of proposed future solution and in-situ mining methods for in-situ leaching and recovery of uranium, gold, silver, and copper. We propose to show that in the future new extraction methods for each metal will eventually evolve for each hydrometallurgical process step, i.e. in-situ leaching, recovery, and concentration; precipitation and reduction; and drying, when required--without generating waste or bleed streams. In the future, to be highly profitable, these forms of mining will develop into an integrated system to eliminate waste streams using safe, powerful lixiviants. This integration will include, with some exceptions, improvements in the following areas of process development: 1. Lixiviant selection and in-situ leaching technique, 2. Target metal recovery and concentration (at a surface hydrometallurgical facility) from the circulating pregnant lixiviant stream, 3. Target metal precipitation or reduction, where decant water from the precipitate dewatering step is reusable for resin or solvent strip liquor (eluant), 4. Final preparation of target metal for sales, i.e. drying, purification, casting, packaging, 5. Restoration where most of the groundwater restoration process is performed at the same rate as multi-wellfield mining.

Jan 1, 1987

By Ross R. Bhappu

Anticipating a major power cost increase in 1990, Cyprus Copper Company decided to modernize the Miami Smelter at a cost of $92.5 million. The modernization project included the addition of an Isasmelt vessel for use as the primary copper smelter and the modification of the existing electric furnace to a slaglmatte separating vessel. The project was completed in June of 1992 and is currently operating at close to its design capacity. This paper provides a summary of the decision making process, a description of the project, a summary of start-up problems and solutions and the current status of the smelter operation.

Jan 1, 1994

By M. R. Robben

Carbonates have gained significant economic importance for the human kind. On one hand over a hundred uses are listed for carbonates. On the other hand, carbonates host base metal deposits. Although the carbonates play a significant part in the development of those deposits, in the mineral processing they consume acid and cause selectivity problems during flotation and leaching. Carbonates also accompany other industrial minerals as waste rock. For all those cases it necessary to find a technique to separate carbonate as early as possible in the processing chain. In this paper, the applicability of near-infrared spectroscopy (NIRS) sorting for the separation of carbonates is discussed. NIRS sorting is a sensor-based sorting technique, in which particles are singularly detected by a sensor and then rejected by an amplified mechanical, hydraulic or pneumatic process. This technique can for example be implemented in the process as a pre-concentration step for coarse particle sizes up to 300 mm. NIRS sorting discriminates among materials based on the difference that exist between their spectral properties in the near-infrared (NIR). Vibrations of molecular bonds in carbonates cause characteristic spectral properties in the NIR, which makes carbonates detectable, possible to identify, distinguish and separate from other rock materials. The spectral properties can also be used to distinguish between different carbonate minerals and mixtures. If the spectral variations are large enough for detection, sorting based on NIRS is possible. Feasibility studies on sensor-based separation of carbonates in the processing of talc, borate, fluorite, marble, zinc-oxides, copper sulphide and iron ore as well as the discrimination of calcite and dolomite mixtures are conducted and indicate the high potential of NIRS sorting in the minerals industry. Keywords: carbonate separation, sensor-based sorting, near infrared spectroscopy, NIRS sorting

Sep 1, 2012

By Randhir S. Sehgal

After some decades of lying low and being treated as a second rate fuel, coal is back in the news. Production is rising. Predictions are for an ever expanding use, and they differ only in their rates of increase. Even the FBI is involved in trying to stop fraudulent sales of non-existent coal lands and leases to the innocent. In short, we have a nearly chaotic boom on our hands. Obviously our energy production base is in the process of undergoing a major shift, and the process will present many problems. However, there is little doubt that the industry has the basic strength and organization to be able to deal with the new issues that will arise as a result of these shifts in production and use of coal. After all, it does produce nearly 800 M tpy now, and coal is the single biggest fuel for generation of electricity. This role of coal is illustrated in the table below, which shows the coal equivalent quantities of various fuels used in the production of electricity.

Jan 1, 1980

By J T. Carswell

Best practice mine sampling should provide a detailed quantification of all potential sources of error at each stage of sampling, sample preparation and assaying.Quality assurance (QA) should include testing for and quantifying potential sampling errors, and should be the basis for establishing ongoing sampling protocols, should set error limits and define quality control (QC) procedures. QA should be within the framework of Theory of Sampling (TOS) but may not involve the estimation of the sampling constant and the application of Gy’s formula.Best practice QC should be carried out efficiently and in a timely and cost-effective manner with regular reporting against the guidelines established by QA.This paper provides an assessment of, and checklist for, current best practice sampling QA/QC with examples from operating gold mines including the QA/QC of underground (UG) reverse circulation (RC) grade control.CITATION:Carswell, J T, 2017. Best practice sampling QA/QC for gold and base metal mining – including how to assess the applicability of underground reverse circulation grade control sampling, in Proceedings Tenth International Mining Geology Conference 2017, pp 297–304 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By G. K. Herzog

THE problems relating to the construction and use o{ mining equipment are basically the same as those pertaining to equipment in other industries. It is true that much mining equipment is subjected to an unusually severe combination of shock, high stresses, abrasive wear, and corrosive ? conditions, but in other industries, also, equipment must operate under similar adverse conditions, so that their experiences may readily be applied to the problems of the mining industry. Steel and iron are for obvious reasons the most suitable materials for the construction of the greater part of the equipment used in the mining industry. For a large percentage of uses, the ordinary plain carbon-steels and ordinary or unalloyed cast-iron are, and probably will continue to be for a long rime, entirely satisfactory materials. There are, however, many. conditions which cannot be satisfactorily taken care of by these materials, and alloy steels and irons must be used where the greatest possible economy is desired. In general, alloy steels and irons are used where it is necessary or economically desirable to use materials possessing properties superior to plain carbon-steel or ordinary cast-irons, such as: (a) better strength (b) better wear resistance (c) better corrosion resistance (d) better resistance to high temperatures (e) better resistance to low temperatures or combinations of two or more of these advantages. There are also conditions where materials having other special properties are required, such as, for example, certain magnetic or electrical properties for electrical machinery; but in the great majority of cases, one or more of the five advantages listed are the most desired.

Jan 1, 1938

By W. A. Crosby

The ability of open pit mines to steepen overall final wall angles allows significant cost reductions as a result of reduced waste movement requirements. Final wall angles are principally controlled by three factors: geological conditions; hydrological conditions; and wall control blasting practices. The first of these factors is not controllable by the mine operator, the second can be influenced to some degree, but the last one certainly can be controlled, hence the current interest in final wall blasting practice at many mining companies. This paper discusses common blasting techniques employed to steepen final pit walls and outlines the attractiveness of moving from small hole high cost systems to the use of full size production drills as a means of reducing wall control blast costs. Attempts to make this change have been limited at many mines by the physical size of the drills and their inability to reverse drill. In the past, pres pi it, pre-shear or trim holes have had to be drilled vertically, at considerable distance from the upper bench toe, with the result that inter-berm face stability is reduced and final wall angles have to be made somewhat more shallow than desirable. The paper concludes with a description of how these problems can be overcome by utilizing the new Bucyrus 39R which has the capability of drilling at a ?15 degree angle underneath the machine. It is concluded that the resulting wall control blast designs will offer large mines improved final wall angles with resulting significant overall cost reductions.

Jan 1, 1998

Discussion of papers with authors' written replies and closing remarks.

Jan 1, 1947

By Joseph F. Shirley

A froth flotation plant to recover by-product molybdenite must be designed specifically for the selected separation process and the type of ore being treated. However, some general rules concerning by-product molybdenite plant design can be suggested that would be valid for most processes. The term by-product molybdenite in this paper is limited to the recovery of molybdenite from copper porphyry ores, which essentially amounts to selectively separating molybdenite from copper and iron sulfide concentrates. In addition, most of the discussions would apply only to the almost universally used approach of floating the molybdenite and depressing the copper and iron sulfide minerals.

Jan 1, 1979

By W. G. Worcester

THE chief object in presenting this paper on bentonite is to attract general attention to one of the least known and most neglected industrial minerals of Canada, a mineral of extensive commercial possibilities, as evidenced by its development and exploitation in other countries, principally in the United States and Germany; countries upon which some of our most important Canadian industries are dependent for their supply of special clays, such as Fuller's earth and activated bentonite. It was in view of these conditions and the knowledge of the presence of large quantities of bentonite in the Canadian West that the work here reported on was under-taken. While the investigational studies have not been completed, the results indicate that among the many samples tested there are some of real merit and industrial importance. While it has been the author's privilege to examine deposits and samples of bentonite from all of the Western provinces, his chief activities in the field and in research studies have naturally been confined largely to Saskatchewan materials. Notwithstanding this, however, this paper is presented in the hope that it may stimulate a more general interest in, and study of, Canadian bentonites as a whole, a matter of such importance that provincial boundary lines should be overlooked. GENERAL CHARACTERISTICS OF BENTONITE According to Schurecht and Donda (1), bentonite is commonly composed of the mineral montmorillonite, (Mg,Ca)O.Al203 5SiO2 .nH2O, though some are known to consist of beidellite, Al2O3 3SiO2.nH2O: where n is approximately 4, and in certain cases the Al2O3 may in part be replaced by Fe2O3. For present purposes, however, it may be sufficient to state that, in general, bentonite is a "soapy' clay-like mineral or group of minerals composed largely of hydrous aluminium silicate, but frequently carrying small percentages of the alkalies, alkaline earths, and free silica, as well as silicates, gypsum, and other admixed detritus such that purification is usually necessary.

Jan 1, 1937

By Ronald B. Stone

This paper describes a proposed solution to the problem of mining a 315 foot diameter unsupported sphere at a depth of 2700 feet in a salt dome by conventional mining methods. The proposed solution utilizes many of the varied technologies available to the mining engineer for solving mining and underground construction problems. The following are reviewed in the paper: A. The location of the sphere within the dome as required by construction criteria. B. The relation of the location of the access shafts to the sphere. C. The rock mechanics theory in relation to the salt dome and large size of the excavation. D. The proposed "honeycomb" method of mining which will be a partial answer to rock mechanics stability requirements. E. The equipment which it is recommended be utilized to accomplish the construction. F. The rock mechanics measuring instruments proposed. G. The methods of disposal of the mined salt. Conclusions and areas of further study are outlined in the final statement.

Jan 1, 1968

By Mohammed Ali Shah, Martin Waller

The mining industry depends to a large extent on the availability of high performance equipment. For drilling this means a requirement for well engineered, reliable machines with mechanised handling and widespread utilisation of automatic control. Such machines enable performance optimisation of drilling operations and integration into a high productivity mining system. A review is presented of the current status of drilling technology as applied to the mining and minerals industry. This covers developments in: drill bit materials and design; drilling techniques; machine design; mechanisation; automation; and drilling control. It also covers the ways in which current and future mining methods and practices will influence the applications and demands placed on drilling activities. The probable impact of current research on the industry is discussed.

Jan 12, 1992

By R. Stach, S. Gola, P. Zgrzebski, K. Soroko

"At the moment climatic conditions are a primary problem of the exploitation of copper ore. The efficiency of preventive actions in order to improve climatic conditions is connected with the knowledge of changing air in underground excavations. This article demonstrates the analysis of types of ventilation dams which are used in sealing abandoned areas on the maintenance of climatic working conditions in excavations has been conducted at the exploitation in Polish copper ore mines. INTRODUCTION The basis for mining activity performed by KGHM Polska Miedz S.A. is mining copper ores from the deposit lying at depths between 600 and 1,200 m below ground level. Activity has continued since 1963. The copper ore deposit is mined in ‘Lubin’, ‘Rudna’ and ‘Polkowice-Sieroszowice’ mines, where difficult climatic conditions occur. The major factor moulding the climatic conditions in headings is the original temperature of rocks, being the result of geological conditions of the lying of the deposit and the existing geothermal degree. In the faces of present opening-out and preparatory headings, driven from mining areas of ‘Rudna’ and ‘Polkowice-Sieroszowice’ mines in order to open out deeper parts of the deposit, the original temperature of rocks reaches 45°C. Excluding the original temperature of rocks, the following are additional factors affecting the deterioration in the climatic conditions: • thermal properties of deposit rocks, • employed room-and-pillar mining systems, which are characterised by a large surface of exposure of rocks, • using self-propelled mining machines with diesel drive, • a high concentration of mining works, • setting up high-power electrical equipment in headings, • complex structures of mine ventilation networks, • a limited number of ventilating shafts, • constantly longer air-transport routes, • a significant accumulation of water increasing the humidity of supplied air. According to the valid Polish provisions (§21, 2013), the primary criterion of assessment of a climatic hazard is the occurrence at a workstation in an underground mining heading of an equivalent climate temperature of more than 26°C, which temperature is determined according to the following dependence:"

Jan 1, 2019

By Onder Guney, Erdem Demirkesenm

"In this study, the crystallization behavior and thermal expansion coefficient of a lithium disilicate (LS2) based glass-ceramic derived from SiO2-Li02-AhO3-K2O-ZrO2 system was investigated by using x-ray diffraction (XRD), high temperature x-ray diffraction (HTXRD), differential thermal analysis (DTA) and dilatometer techniques. Analytical reagent grade chemicals were chosen as raw materials for preparing glass batches. Nucleation and crystal growth heat treatments were planned according to DTA results. The amounts of the amorphous and crystalline phases developed during the heat treatments were determined by quantitative XRD. XRD results of crystallized samples showed simultaneous formation of lithium silicate (LS) and quartz in the early stage of the crystallization followed by formation of lithium disilicate (LS2) at higher temperatures. The thermal expansion coefficients of glassceramics were also measured depending on the applied heat treatments.IntroductionSignificant developments occurred in all ceramic materials provide the fabrication of high quality dental implants [1]. Glass ceramic based dental restorations like dental inlays, crowns, bridges and veneers are becoming increasingly popular with their reliable and durable performance [2,3]. In addition to their advanced functional properties, glass ceramic implants especially lithium disilicate glass ceramics also face the esthetics expectations of patients and dentists and in this way they are starting to take the place of metal based restorations today [1,3,4,5]. Lithium disilicate glass-ceramics derived from multicomponent glass systems have some superior mechanical and optical properties comparable to natural teeth [ 6]. In restorative dentistry, mechanical characteristics of biomaterials play very crucial role in order to resist the masticatory forces occurred during biting and chewing [7] According to three point bending test results of Roland, flexural strength of the lithium disilicate glass-ceramics were 400±40 MPa and their fracture toughness (K1c) are approximately 3,3 MPa m112 [2,6]. In addition to high mechanical strength, aesthetic appearance is another important prerequisite as material for dental restorative applications. Translucency and light transmission of the LS2 glass ceramics mimic enamel. Moreover, opacity of the material can also be adjusted depending on the restoration types [2,6, 7]. These superior properties of the LS2 glass ceramics are directly related with chemical composition of the base glasses and controlled crystallization heat treatments [ 4, 7]. The aim of the present work is to determine the effect of heat treatment schedules on the crystallization behavior and thermal expansion of the LS2 glass-ceramics."

Jan 1, 2011

By H. Habenicht, E. Urschitz

Three mining methods for full extraction in flat coal seams - i.e., longwall (L W), shortwall (SW), and rib pillar extraction (RPE) - are com- pared with each other in view of the introduction of a mechanized, self-advancing roof support. Features are shown according to which RPE appears most attractive under certain conditions. In this presentation, the mining methods are outlined and discussed. The new support (Alpine Breaker Line Support, ABLS) is described, and its employment is explained. A trial operation in RPE using the ABLS has been conducted successfully in a South African coal mine. The results and improvements are stated.

Jan 1, 1988

By I. H. Clark

A variety of backfills is presently being placed in different gold mines. The backfills are pumped as slurries to stopes where they are discharged into some form of retaining paddock. The effectiveness of fill as a support medium will depend on a number of factors. These can largely include (i) inherent properties of the material, e.g. particle size, shape, distribution and com- position, and (ii) conditions of placement. The terminology required for describing backfills is introduced, and the various laboratory-measured properties are presented for a variety of fills. Finally, the properties of the fills as they are placed underground are discussed.

Jan 1, 1988

By Minchinton A

CPeX is a non-ideal explosive performance prediction model. The model takes into account the rate of energy release, the extent of chemical reac- tion and the effect of confinement on energy release. The model resolves the explosive energy into `shock' and `heave' com- ponents as a function of explosive type, hole diameter and rock type. The predictions of the model are compared for a bulk emulsion, and a prill-doped bulk emulsion in soft rock. The predictions, based on calibra- tion of the model with simple unconfined detonation velocity measure- ments, show the significant effect of non-ideality on explosive Performance.

Jan 1, 1988

The Bellambi Coal Company Limited com menced longwall mining at South Bulli Colliery in 1965. At present it operates three long- wall units in two seams. Although results to date have been less successful than planned, it is apparent that this type of mining has tremendous potential in the particular conditions at South Bulli. Massive sandstone strata above the Bulli seam is the controlling influence on face conditions. The earliest equipment proved to be inadequate and the Company has progress- ively replaced and upgraded the roof supports and ancillary equipment so that the present units are capable of producing high and consistent outputs.

Jan 1, 1976

By Yingzin Zhou

Partial backfilling can be used to reduce and control surface subsidence damage caused by longwall mining or pillaring operations in room-and-pillar mines. The use of partial backfill as opposed to total backfill minimizes the cost associated with such efforts. By com- paring surface subsidence, strains, and slopes, the effectiveness of partial backfilling including the amount, geometry, and location of backfill are demonstrated. Results show that it is possible to arrange a given volume of backfill in its geometry and location so that optimum effects are achieved in controlling vertical movement, surface slope, and curvature.

Jan 1, 1990