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By A E Reschke

The high-shear colloidal mixer is generally recognised as the most efficient method of mixing cement based grouts. Only recently however has this technology been applied to the production of cemented rockfill (CRF) for use in underground mines in North America. Traditionally, paddle type mixers have been used to produce the cement based slurries required for the preparation of CRF. While considerable success has been achieved with these mixers, tremendous advantages are attained with the colloidal mixer. The combined effect of the highly efficient mixing action and the ability to mix low water/solids ratios, allows for reductions in the cement content for a given strength requirement. Cement can also be replaced by cheaper fillers such as flyash, resulting in further cost savings. Although large-scale dedicated CRF hatching plants are typical, there is a growing need for mobile plants capable of operating anywhere underground. The compact size and rapid hatching speed of high-shear colloidal mixers has allowed them to be incorporated into skid mounted systems capable of producing and discharging cement based slurries onto rockfill aggregate for the production of CRF. In many cases run-of-mine development waste can be used as CRF aggregate with these slurry plants thereby reducing the cost of waste rock removal. These relatively low cost portable plants have now allowed several mines to economically rccmer isolated pillars and realise positive returns on their investment.

Jan 1, 1998

The high-shear colloidal mixer is generally recognised as the most efficient method of mixing cement based grouts. Only recently however has this technology been applied to the production of cemented rockfill (CRF) for use in underground mines in North America. Traditionally, paddle type mixers have been used to produce the cement based slurries required for the preparation of CRF. While considerable success has been achieved with these mixers, tremendous advantages are attained with the colloidal mixer. The combined effect of the highly efficient mixing action and the ability to mix low water/solids ratios, allows for reductions in the cement content for a given strength requirement. Cement can also be replaced by cheaper fillers such as flyash, resulting in further cost savings. Although large-scale dedicated CRF batching plants are typical, there is a growing need for mobile plants capable of operating anywhere underground. The compact size and rapid batching speed of high-shear colloidal mixers has allowed them to be incorporated into skid mounted systems capable of producing and discharging cement based slurries onto rockfill aggregate for the production of CRF. In many cases run-of-mine development waste can be used as CRF aggregate with these slurry plants thereby reducing the cost of waste rock removal. These relatively low cost portable plants have now allowed several mines to economically recover isolated pillars and realise positive returns on their investment.

Jan 1, 1998

By Junya Tokita

In Japan, packaged explosives have traditionally been used as the most common explosive for tunneling. Recently, some blasting systems such as ANFO with a kettle loader and emulsion explosives with a pump loader have been trialed in order to improve safety and efficiency of the charging process. There are issues with these systems relative to the Japanese market. ANFO dissolves in water easily, and generates ammonia gas when it contacts with concrete. Emulsion explosives need costly pump ing unit s, and there is a need to control residuals in the pump unit. Additionally, there are obstacles by Japanese law to site mixing of emulsion explosives.

Jan 1, 2005

By M. S. Kabibwa, E. K. C. Chanda

In planning for the future, Nkana Division deepened the Mindola sub-vertical shaft which was commissioned in 1994 in order to access the 30 Mt of ore between 1274 and 1570 m levels. The Nkana Synclinorium which is estimated to contain 250 Mt of ore is being accessed from the vicinity of Central Shaft. These areas are being planned with the intention of maximizing the use of computers in geological modelling and mine design so as to overcome the inadequacies of manual planning techniques. As a result, there is an increased demand for quality output from the computerized mine planning system the division has been developing over the last few years. A new workstation comprising the Hewlett Packard HP 71 51100 MHz and a CRX graphics monitor was acquired in 1995 together with the LYNX (version 3.09 and version 4.0) Mine Modelling System. Currently the workstation is being used for geological modelling and mine design for the Zerofold at Central Shaft and the Mindola mining at depth project. AutoCAD and Mine Works Planner have been added to the sys- tem configuration. Mine Works Planner is likely to replace Lo- tus123 for mine scheduling tasks. Computer applications in the area of mine planning at Nkana has led to considerable time savings and improved efficiency in areas formerly performed manually and has allowed speedy processing of data that would otherwise have proved too time consuming. Nevertheless, a lot of work still needs to be done in the areas of geostatistics, stope design and financial modelling of mining options. For the foreseeable future computer based planning will operate parallel to manual methods until such a time as sufficient personnel are proficient in the use of computer systems. This paper describes the program of computerization at Nkana Division, reviews current applications and the benefits and experience gained and discusses the promise of current and future developments.

Jan 1, 1996

By A. K. Haines

The status of the South African research and development programme on continuous ion exchange, which was aimed at the technical and economic assessment of that process for the recovery of uranium, is reviewed. The first phase of this programme, which has now been completed, involved development investigations on various pilot plants and culminated in the successful operation of a large-scale demonstration plant and the incorporation of the system in a number of new South African uranium plants. This account highlights the engineering aspects and the design fo the system, its adaptation to process flowsheets, and plans for future development.

Jan 1, 1978

By T. W. Camm

One function of the U.S. Bureau of Mines is assessing potential economic impacts of federal land withdrawal policies. This often requires performing economic ana1ysls for an area with limited geologic information available. Input to the economic decision process relies heavily on estimates of mine and mill costs for the potential resources in the area being considered. A methodology for performing these cost estimates was needed to address this situation.

Jan 1, 1992

By C R. Ure

To substantially reduce, if not eliminate, carbon dioxide (CO₂) emissions from ironmaking it is necessary to convert from blast furnace (BF) ironmaking using coking coal as the reductant to direct reduction (DR) ironmaking using hydrogen (H₂) and green electricity. Currently, almost all natural gas (NG) based direct reduced iron (DRI) production utilises iron oxide pellets in shaft furnaces, as opposed to fines in fluidised beds. Also, these pellets are ordinarily produced from high-grade magnetite concentrate, rather than hematite and goethite with typically higher gangue contents. The use of high-grade magnetite concentrate is driven by the preference to melt DRI in conventional electric arc furnaces (EAFs), thereby avoiding the basic oxygen furnace (BOF) for making crude steel (CS). However, in replacing BF with DR ironmaking it is not economically feasible to source enough high-grade magnetite to replace the lower grade hematite and goethite currently consumed. That is not to say that hematite and goethite, or even low-grade magnetite, cannot be used in DR ironmaking. However, their higher gangue content, resulting in higher slag production, requires that the EAF producing CS be replaced with a submerged arc furnace (SAF) that will produce pig iron (PI) for the BOF as does the BF. Here, critical issues to be addressed are, what are the technicalities in replacing high-grade magnetite concentrate with hematite and goethite and NG with H₂ in DRI pellet production and melting? This paper summarises certain relevant published information on DRI pellet research, test work and production together with relevant information on Pilbara ores. It attempts to illustrate the inter- relationship of composition and processing conditions on DRI pellet properties. It is intended to serve as a rudimentary guide to understanding the complexities of formulation, testing, evaluation, production and goethite and offer insight into this challenge.

Sep 18, 2023

By M. J. H. Tonkins, C. C. Crosson, G. Paterson

The development of drilling and blasting practice at Palabora Mining Company Limited by c. C. CROSSON, Pr. Eng., A.C.S.M. (Hons), BASe. (Min. Eng.) Toronto, M.!.M.M. (Member), M. J. H. TONKING, Pr. Eng., A.C.S.M., BASe. (Min. Eng.) Toronto, M.I.M.M. (Member), and G. PATERSON, B.Se. (Min. Eng.) Glasgow, M.!.M.M. (Visitor) Open-pit drilling and blasting practice at the Palabora Mining Company Limited is described, with particular reference to the development of aluminized slurry explosives. Rotary drilling of primary drill holes, drilling patterns, and blasting techniques for use with slurry explosives are described.

Jan 2, 1976

By Helena Byrdziak

KGHM Polska Miedz S.A. is a significant European copper producer with production of 447,000 mtpy, operating three underground mines and three smelters. The company has been involved for years in environmental activity, which was stimulated not only by the company itself, but by the development of environmental regulations as well. The first set of regulations, concerning water protection, was' established in Poland' in 1974, while a comprehensive environmental law was passed in 1980. This law in general requires industry to submit all data of environmental significance to the local authorities. Based on this data, they establish limits concerning emissions into the air, water and ground, the amount of wastes produced and the means of their disposal. A company has to pay fees for each tonne of emitted substances and stored wastes. When the emission of a substance exceeds the limit, the company has to pay a penalty which is about ten times higher than the fees. This approach in general is effective because it forces companies toward: reduction of their emissions. The problem is that the law is constantly subject to change and is becoming not only more restrictive but is involving more and more bureaucracy.

Jan 1, 1999

Acupan is considered to be an intrusive centre as several igneous phases have been emplaced in the vicinity of the mine over the past 8 Ma. They include the Lucbuban gabbro, Virac granodiorite, Ampucao dacite porphyry (ADP), Hartwell plug, Itogon plug and the multi-phase Balatoc diatreme. These intrusives have high-K calc-alkaline affinities and are grouped together as the Virac Complex.Porphyry-style mineralisation formed during the final crystallization of the ADP in the late Pliocene, with the deposition of two vein stages from high-temperature hypersaline magmatic-hydrothermal fluids. K-silicate alteration halos surround the first stage of veinlets (stage I); they are surrounded in turn by a propylitic assemblage. White sericite and/or intense propylitic halos envelop the second stage of veinlets (stage II) and grade into a weak nrnnvlitir accPmht o

Jan 1, 1990

By Paul R. Wieber

This paper describes the U. S. Energy Research and Development Administration's (ERDA) program to develop in situ coal conversion processes, especially gasification, he potential of this technology, the technical directions being explored, and the program strategy to carry the process concepts toward commercialization are emphasized. The geographic location of the U. S. coal resources and a market analysis are described. Commercially successful in situ coal processes could add over a trillion tons of coal to the U. S. coal reserves. The economics of these processes is compared with surface gasification independent studies show this process to be 25Z cheaper than surface gasification for Western coals. The major projects are briefly described. The Linked Vertical Well process is in the lost advanced stage and shows great promise. The last test produced a low-Btu gas averaging 171 Btu per standard cubic foot for average pro¬duction rates of 5.5 million standard cubic feet per day. The other projects are Packed Bed, Longwall Generator, and Steeply Dipping Beds.

Jan 1, 1977

By ev, Ze&apos Reches

The growth of networks of shear fractures is explored in a series of experiments with samples of wet clay. The samples are subjected to plane strain deformation in a rigid apparatus. The individual fractures observed on the upper surface of the clay samples grow longer by three mechanisms: in-plane propagation, off-plane propagation and coalescence. New, active fractures cut and displace older, less active ones. The lengths of individual fractures display lognormal distribution in most cases and power distribution in fewer. The calculated length parameters in the experiments, as well as in three field cases discussed here, suggest that the fundamental parameters in fracture analysis are the normalized cumulative length and the length of the shortest fracture measured.

Jan 1, 1986

By G. E. Cole

"Amongst the mineral products of Canada gold holds the second place in value of yearly output. . . . . .The production of gold has increased steadily during the past six years and has somewhat more than doubled in that time. For the past four years Canada has been third among the gold producing countries of the world, surpassed only by the Union of South Africa, and the United States of America," and now yields somewhat more than 9 per cent of the annual output of the world."-"The Gold Situation in Canada". Bulletin of Development Branch, Canadian Pacific Railway. The history of gold mining in Canada is comparatively modern and does not take one further back than the late 'fifties of the 19th century. If the efforts of the early explorers in Canada were expended in "seeking with equal ardour, proselytes and gold", history fails of any record of their success in the search for the precious metal. As early as 1849 not a few Canadians travelled from the east by land and water to the Californian goldfields. In the then settled part of Canadathe east-people were alive to the value of any mineral discovery; but the west, owing to its remoteness and to there being no ready means of communication, was virtually isolated from the east.

Jan 1, 1927

By Morley I. W

In the year 1926, Edie Creek, in the Morobe District of the Mandated Territory of New Guinea, saw the greatest gold rush of recent years. Situated 35 miles inland from the coast, and at an altitude of over 6000 feet, Edie Creek presented to the original prospectors a wet, jungle-clad uninhabited, and inhospitable region. There were no roads; and the only means of approach from the equally inhospitable coast was by an eight to ten days' tramp through coastal swamps and gorge-scarred mountains. All food supplies and equipment had to be carried on the backs of "kanakas," and in many cases through country occupied by hostile natives.Since the first discovery of payable gold at Edie Creek, mining on the Morobe Goldfield has shown remarkable progress, and in spite of the tremendous natural difficulties, the field today ranks as one of the most important in Australasia.Aeroplanes, more than any other factor, have been responsible for this rapid development. They provide the only means of transport from the coast, and at present serve the needs of over 600 Europeans and 3000 indentured native labourers engaged in the industry.

Jan 1, 1933

By L. V. Kin, V. V. Lodeischikov, A. V. Byvaltsev, IRGIREDMET JSC, O. D. Khmelnitskaya, S. V. Petrov

"Irgiredmet Institute carried out the study on the development of gold recovery technology from refractory ore from a Russian deposit. The ore contained 1.1 g/t Au, 1.5% of pyrite and 2.4% of pyrrhotite. The recovery of gold achieved was 84.7% using gravity with generation of high grade recoverable gold concentrate and gravity middling. In the course of lime treatment, cyanidation of the middling followed by tailings detoxification the consumption of reagents was 13.0 kg/t CaO, 95 kg/t NaCN and 72 kg/t Ca(OCl)2 of the concentrate. This was capital intensive.In order to decrease the consumption of reagents, magnetic separation of the middling of the concentrates from gravity separation was added to this flow sheet. Pyrrotite recovered to magnetic fraction, which did not contain gold in accordance to this advanced flow sheet. The mass yield of pyrite goldbearing non-magnetic fraction decreased down to 1.5 times in relative to gravity middling. The slurry filtration prior to and after cyanidation allowed the organization of cyanide solution recycling.The results of pilot plant tests using the developed flow sheet showed that the content of pyrrhotite in the non-magnetic fraction decreased from 59.1% to 11.3%. The reagents consumption was 12 kg/t CaO, 3 kg/t NaCN and 16 kg/t Ca(OCl)2 of the pyrite concentrate. The total gold recovery using this flow sheet was 83.4%. Due to a decreased consumption of reagents, cost efficiency of the process was achieved. Based on the results of this research, a project design criteria was developed. A processing plant with the annual throughput of 2.6 million tonnes of ore is being designed."

Jan 1, 2016

By RT White

For a number of years the steel tube and pipe industry has worked on resolving problems of product quality. These have largely been resolved and new products have been developed to take advantage of new developments. To fully coordinate market acceptance guidance on use of galvanized piping was also required. This was largely achieved locally in 2004 with the publication by the SABS of ARP 060 - Guidance on the use and application of hot dip galvanized steel piping for the transportation of potable water in South Africa. Use of this document is not easy however and a need to have a simple computer model to assist the specifier was identified. Working with a major tube and pipe manufacturer this is now being developed and this paper will provide the background to the model?s development and its intended use. There is still a need for a partner Code of Practice on the performance of galvanized piping in buried conditions and the need for this will be highlighted together with current available information.

Jan 1, 2006

By Floyd M. Thorman

Gypsum is the crystalline chemical compound CaS04?2H20. A close chemical relation - and frequently occurring with Gypsum ? is Anhydrite which is Cask. Gypsun has wide commercial use because relatively simple heat processing reduces it to Plaster of Paris. While Anhydrite can be converted to Gypsum and thence to Plaster of Paris, the procedure is not simple and is quite costly. Anhydrite, however does have use in the agricultural field and in the Portland Cement industry. Occurrence of Gypsum in the earth structure is usually near or at the surface. Most underground mining is at 60 to 100 feet although one mine in southwest Virginia reaches a depth of 1300 feet. Gypsum is one of our softest minerals, rating only 2.0 on the Mohs scale of hardness. Specific gravity is 2.3 to 2.4. It is soluble in water but only slightly so. Interestingly, it is more soluble in cold water than in hot. For example, one part Gypsum dissolves in 370 parts water at 106° Fahrenheit while at 212°F. the water requirement is 452 parts. Compressive strength of massive Gypsum runs about 3000 lbs. per square inch. Color ranges from grey and brownish-grey to white.

Jan 1, 1973

By S McKnight, L Koroznikova, S Hall

Mineral sands represent an important new resource being developed in the Murray Basin, including parts of western Victoria. This paper will outline a simple methodology for mineral sands characterisation, developed as part of the AMIRA-managed project P777 æThe Development of Heavy Suspension Techniques for High Density Separations (Replacement of ClericiÆs Solution)Æ. This project is currently sponsored by three multinational mining companies (De Beers Consolidated Mines, Iluka Resources Limited and Rio Tinto Limited) and is developing an innovative laboratory mineral characterisation procedure that will allow the replacement of the currently employed highly-toxic chemicals.Mineral sand resources almost always contain more than one valuable (and relatively heavy) mineral. Titanium minerals are found with a large range of titanium contents, giving rise to density variation and often subjective mineralogical descriptions. Companies tend to rely on laboratory heavy liquid separation in the evaluation of samples arising from exploration, mining or metallurgical processes. Unfortunately, there are only a limited number of high density (æheavyÆ) liquids and these tend to be more toxic as their density increases. Low-toxicity inorganic solutions, based on tungsten compounds, have been developed that can be utilised at relative densities (RD) up to 3.0. However, beyond this value currently only organic liquids can be used. Diiodomethane (methylene iodide) having a relative density of 3.31 is commonly used; however, this presents significant health and safety hazards. Mixtures of thallium formate and thallium malonate were found in the early 1900s by Clerici to provide liquids having specific gravities between 4.0 and 5.0, hence æClericiÆs solutionÆ. For the characterisation of the heavy components of mineral sand deposits (eg anatase sg 3.9, rutile sg 4.2, ilmenite sg 4.4 û 4.7 and zircon sg 4.6 û 4.8) there is currently no heavy liquid alternative to ClericiÆs solution. ClericiÆs solution is highly toxic and testing is now conducted by very few laboratories worldwide with costs reflecting the chemical costs (though extensive efforts are made to recover and reuse the liquid, plus the requirement of its removal from the mineral samples), the infrastructure costs and health and safety regimes (eg blood testing of exposed staff, inventory management). A simple laboratory technique of density fractionation is being developed, employing suspensions of fine tungsten carbide particles in lithium heteropolytungstate (LST) solutions, that can replace ClericiÆs solution in the evaluation of fine mineral sands samples (eg -250+150 microns). The developing methodology that can achieve low-cost, low-toxic separations at relative densities above 5.0 will be outlined and the comparison of results with ClericiÆs solution presented.

Jan 1, 2006

By Ritchie IC

Spiral separators have been used to treat heavy mineral sands in Australia for some thirty-five years. They were used as the primary treatment method until the advent of the Reichert cone, which largely replaced them, due to its compact design and relative ease of operation. Spirals continued-to be used as the final cleaning stage before dry separation of the heavy minerals as they remained the most efficient separator for this purpose.

Jan 1, 1986

By J. Baz-Dresch

A custom-designed shotcrete system, consisting of an 8-m3 (10-yd3) transit mixer and a shotcrete spray boom carrier, is used bya 2-man crew to transport and place up to 25 m3 (32 yd3) of steel-fiber reinforced, dry, silica fume shotcrete per II-hour shift. Shotcrete is custom blended by a local supplier and delivered predampened. Mix design and quality control is performed with a computer program that develops and graphs a properly balanced mix based upon the materials sieve analyses.

Jan 1, 1991