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Much interesting data on cemented carbides has been published over a period of years which, when classified and pieced together, gives a clear picture of this special branch of powder metallurgy. This is an attempt to present the essential information in an ordered account.THE HARD CARBIDES-THEIR PROPERTIES AND PREPARATIONThe so-called hard or refractory carbides are the carbides of a number of metals which are grouped together in the Periodic Classification. These metals are in groups IV, V and VI. They are titanium, vanadium, chromium, zirconium, niobium (columbium), molybdenum, hafnium, tantalum and tungsten. These carbides have attracted the attention of chemists because of their remarkable properties. They possess very high melting points, and are rather difficult to prepare in the pure state. Their outstanding propertyis their extreme hardness, which they share with certain other carbides, such as those of silicon and boron. In addition, these compounds possess distinctly metallic properties, such as lustre (in fused specimens) and high thermal conductivities.(l)t They are capable of forming alloys in two ways:1. With metals, particularly those of the iron group. 2. With each other (a case of solid solubility).The constitution of these substances is not that of ordinary salts, which obey the usual valency rules, but must be likened to that of certain intermetallic compounds. Actually they are "interstitial" compounds(2), that is, they are formed from the ordinary metallic lattice by the insertion of the relatively small carbon atoms in the interstices.. The energy required to fill the lattice completely is high, and this explains the difficulty often found in obtaining the exact stoicheiometric compound. Thus the carbides can have a range of composition, and can be considered as solutions of carbon in the respective metals.Physical Properties of the CarbidesThe hardness of these compounds is so great that it is difficult to compare the individual compounds on this basis. Becker(l) gives values on Moh's scale, which are not very accurate and are of no great value. Burden(3) has reproduced a diagram by Hatfield which indicates that the cemented carbides are between 1,400 and 2,000 on the Vickers diamond scale. However, the pure carbides are harder, tungsten carbide being about 2,200. Hoyt(4) describes a method of measuring hardness applicable to powdered specimenswhereby the powder is rubbed on a standard block of cemented tungsten carbide under standard conditions, and the rate of wear is determined. In...

Jan 1, 1942

Mount Read is 'situated in the county of Montagu, on 'the west coast of Tasmania, about 20 miles inland from. Remine in an easterly direction, 15 miles northerly from Mount. Lyell, and 30 miles south-east from Mount Bischoff, and is one of the mountains forming the west coast range; it rises to a height of 3890 ft. above sea level.About eleven years ago the first mineral section was taken up on Mount Read by a Hobart company, known as the Mount Reid Silver Mining Company, consisting of 25,000 shares its holding consisted of one section of 80 acres, held under mineral lease. Prospecting was carried on for some months under great disadvantages, as all supplies had to be carried up the mount from Dundas, a distance of nine miles, on men's backs, until a pack track for horses was made.The track rises 2500 ft. in the first five miles, and then falls 200 ft. from that point to the mines, which are at an altitude of 3000 ft. above sea level, and at a point about two miles westward from the summit of the mountain, approximately midway between Mounts Read and Dundas.

Jan 1, 1901

THE Talisman mine is situated on the Waitawheta (pronounced Wytaffetta) river just above its junction with the Chinemuri (pronounced Chinnemurre) river near Karangahake, NZ. The explored reef-bearing portion of the claim includes the angleformed by the junction of the rivers and extends southwards for slightly over a mile (See Plate V.). The country is mountainous both rivers flowing through precipitous gorges.The trig. station on Karangahake mountain is almost directly above the workings on the Bonanza section and is 1680 ft. above river level, the adit from the gorge giving 1200 ft. of backs measured vertically. The officers of the N.Z. Geological Survey are engaged in a detailed survey of the Waihi district and the rocks of Karangahake are under examination. The rocks of the district are andesites and dacites much altered and silicified. One of these exhibits a columnar structure in the mass in the Waitawheta gorge near the surface workings on Taukani hill, also on the southern bank...

Jan 1, 1912

Mining is a fundamental activity on which modern society and the world's economy are entirely dependent. Mining investors, large and small, invest on an international scale, frequently being active in several countries.   Prior to committing investment to new countries, the prudent investor will consider the risk involved by analysing a number of physical, financial, administrative and political parameters that impact on the potential financial returns it is seeking. This paper considers these risk factors in relationship to New Zealand and six competitor countries. The conclusion is that for reasons largely within the control of our politicians, New Zealand is a high risk country for mining investors.

Jan 1, 1993

By Lyman G. J

Dense medium drum separator efficiency was analysed at two Western Australian iron ore concentrators. Efficiency data had hitherto been difficult to accumulate due to the high cost of analysing representative, and therefore large, coarse ore samples. To overcome this problem, recoverable density tracers, which are in effect artificial mineral and gangue, were manufactured in three different sizes (15 mm, 30 mm and 60 mm). Their use enabled partition curves to be studied within one hour of conducting a test: separation densities were generally lower than the feed medium density for all three sizes of density tracer. For a given set of operating conditions, the smaller tracers had lower separation densities and larger ecart probab/es than the large tracers. These phenomena are explained with the aid of a conceptual model of a drum separator, which assumes that the feed ore plunges to the bottom of the drum upon introduction. Particle rising velocities are, therefore, process determining.Medium rheology was altered by adjusting the proportion of solids in the pulp. This was accomplished by changing both the pulp density and ferrosilicon/magnetite ratio. Higher solids volume fractions invariably caused a decrease in separation densities and an increase in ecart probables, most markedly for the smaller tracers. A similar response was observed when feed tonnages were raised.An explanation for these phenomena is sought in the discussion which also suggests means of improving drum separator efficiency.

Jan 1, 1987

The mineral matter has been isolated from a selection of Australian bituminous coals using low temperature (radio-frequency) oxidation or hydrogen peroxidation techniques and the species present identified by x-raydiffraction. Quartz, kaolinite, and a range of mixed layer clay minerals are the dominant constituents of the coals studied, with carbonate, sulphate, and phosphate minerals abundant in some samples. The clay bands thatoccur within these coal seams contain similar mineral assemblages to the coals themselves, but the lutites that form the inter-seam strata have a markedly different mineralogy, characterized by abundant quartz andillite and a low kaolinite content.The kaolinite is thought to have formed chiefly by interaction of silica and alumina in the waters of the coal swamp, aided by the catalytic action of organic acids, while most of the other clay minerals are probablydetrital. The absence of illite from Australian coals is not fully understood, but it may reflect the action of organic acids on the detritus in the swamp, coupled with deposition in freshwater rather thanmarine conditions. Pyrite, although present in some coal samples when fresh, may undergo oxidation during storage to form a number of sulphate minerals, some of which may interact with any calcite present toform gypsum.The mineral matter assemblage in the coal determines to a great extent the fusion characteristics of the ash.Unless abundant carbonates are present, coals with kaolinite-rich assemblages have a very refractory ash, while those rich in chlorite or montmorillonite have ash fusion temperatures between 1000 and 1300°C. Theinfluence of the minerals on coal preparation and coking properties is also brieflY discussed, as well as the potential of mineral matter studies in coal seam correlation.

Jan 1, 1978

Classification within the Inferred Resource category is based on geological judgement and the balance of extrapolation versus interpolation that the Competent Person is prepared to accept. These resources are typically drilled at spacings well in excess of the geostatistical range and at a density that is non-uniform. In many cases, a substantial proportion of the available data will be historical, and should be considered with more recent data sources. The provision of a robust geological model will increase the confidence in any resource estimate, and should be viewed as a critical component. The definition of Inferred Resources is of great importance to vein gold projects, since Indicated and Measured Resources generally require costly underground development for delineation. Indeed, many gold vein operations possess substantial quantities of Inferred Resources (>75 per cent) in their resource inventory both at project start-up and during production. This contribution explores a number of the key issues when using the Inferred Resource category and presents four recent case studies.

Jan 1, 2006

The ore treatment expansion programme at Mount Isa Mines required the erection of a new lead-zinc concentrator to be known as No. 2 Concentrator. This concentrator was designed by Western-Knapp Engineering Company in conjunction with staff of Mount Isa Mines Limited. Metallurgical design followed conventional wet milling practice, but the size of many plant units is larger than previously used at Mount Isa. The. total capacity of the new plant is 150,000 tons per four weekly period, and the plant is designed to operate in two equal parallel sections.Erection was contracted on a turnkey basis, and the plant was commissioned as a production unit on 23rd June 1966.The existing concentrator, No. I, was converted to treat all copper ore, and the total capacity of the two plants is now 390,000 tons per four weekly period.

Jan 1, 1968

By S Telford, J Weir

Heathgate Resources Pty Ltd (Heathgate) operates the Beverley Uranium Mine in South Australia, located on the plains between the northern Flinders Ranges and Lake Frome some 600 km north of the state capital Adelaide. The uranium orebody exists in permeable sands within the confined, highly saline Beverley aquifer, approximately 125 m below the ground surface and the uranium is mined using in situ recovery (ISR) technology. The Beverley mine is a highly technologically advanced ISR mine and is operated in accordance with stringent safety and environmental standards. The mine is currently licensed to export 1500 t of uranium oxide (U3O8) per annum. This paper outlines the fundamental differences between ISR operations and the more traditional uranium production methods, such as agitation leaching and heap leaching, where the ore is removed from the deposit, stockpiled, crushed, milled and leached on the surface. Solids tailings from either the mill or the heap are finally deposited in a tailing storage facility. ISR mining differs from conventional mining because the ore remains in place underground (in situ) and the groundwater contained in the ore-bearing aquifer is utilised as the mining fluid. This is achieved by drilling into the deposit and installing wells for extracting and re-injecting the groundwater which is fortified with chemicals. The fortified groundwater (ie mining fluid) flows through the permeable sands containing the orebody, dissolving the uranium. The pregnant mining fluid is then collected and transferred to the recovery plant where the uranium is captured (on ion exchange (IX) resin in the case of Beverley). The barren mining fluid is then re-fortified and recycled to the wellfields. Once mining is completed in a wellfield, the surface infrastructure is relocated to a new wellfield, and the mined-out wellfield is rehabilitated to its original surface condition. A comparison of 'standard' hydrometallurgical plants, heap leach and ISR shows a number of key differences, such as the rate of leaching, the level of control available to the operators, and the type of contact/reaction that occurs. While limited in its applications, ISR mining has proven successful at Beverley and provides another mining and processing method for the production of uranium.

Jan 1, 2008

The material presented in this paper describes experimental work to determine the effect of variations in suction nozzle design upon inlet flow conditions. Four entrance profile shapes were examined under controlled conditions of slurry flow and it was found that the straight ended nozzles had consistently higher entrance losses than the straight taper or the ellipse, and that the circular arc profile nozzles were the most efficient. Subordinate considerations were the measurement of the quantities and the forces involved.As the work progressed, three distinct phases in the pattern of flow were apparent and the static pressures in each were carefully examined. An inlet zone was found to be unstable in changing boundary conditions, a transition zone was largely independent of slurry density and in a zone of stability the pressures were found to be directly related to the characteristics of the flowing pulp. In this zone pressure measurements were reproducible within ± 2 per cent regardless of changing boundary conditions.The effect of varying the "1" parameter of nozzles with a part circular entrance profile was examined and it was found that flow conditions approaching the ideal were obtained when the radius of curvature was between 0·40 and 0·550.

Jan 1, 1966

A wide-ranging base of jig data was collected from various types of commercial jigs in 9 coal preparation plants in China, and a complete data analysis was made. It was found that the sharpness ofseparation was very variable, which demonstrates the complex interplay of the many factors which influence jig performance. Tests showed that there exist optimum frequency ranges in each compartment of a jig. Stepwise regression analysis indicated that the sharpness of separation is most sensitive to the intake fraction ofthe air cycle, the frequency, and the feed rate. By means of non-linear curve fitting techniques and statistical analysis, several mathematical models were developed to describe both partition curve and the jig performance, for simulation purposes.

Jan 1, 1986

Metana Minerals commenced life in 1970 and graduated to a mining company in 1981 with the opening of a small alluvial tin-tantalite mine at Wodgina (W.A.) The present board of directors assumed control of the company in 1978 and established the exploration and development philosophies that have guided the company's expansion to its present status as an emerging diversified miner. An ability and willingness to raise equity capital when required has been a feature of the company. Company activities include exploration for gold, diamonds, heavy mineral sands, polymetallic (base and precious metals) deposits, strategic minerals, rare earths, oil and gas in a geographical distribution covering the entire Australian mainland Metana owns and/or operates four gold mines (Reedy, Mt Magnet, Youanmi and Howley) and at the time of writing is developing a fifth gold mine - its first underground mine - at Rothsay. In contrast to many similar or larger sized companies, Metana undertakes most activities itself rather than through the use of consultants or contractors. In-house services include: analytical and metallurgical laboratories, plant engineering design and construction, drilling and mining (earthmoving) Metana Minerals has established an enviable reputation for technical excellence and this expertise has placed the company in a sound position to continue its growth pattern into the future. This growth will be achieved through a combination of low cost and successful exploration and acquisition of suitable mines either directly or through corporate activity.

Jan 1, 1989

THE science of topography deals with the various natural and physical features of the earth's surface. These features are determined by the manifold constructive and destructive processes of nature, and their many diverse forms and characteristicsare dependent primarily upon geologic structure. Thus it is that a close relationship exists between the rocks of a region and the topographic features of the lJountry wherein they occur. Again, the existence of all sorts of mineral wealth is dependentupon the nature of the rocks, and their extension is directly connected with the topographic features represented upon the enclosing land-area.In studying any district with a view to deciphering its geological structure, to locating any mineral deposits it may contain, and to ascertaining, so far as a surface-examination may show, their probable and economic possibilities, it is therefore ofprimary importance to have at hand a correct topographical map of the area under investigation.GENERAL REMARKSThe actual amount of topographic detail shown will depend upon the money and time available for topographic surveying and upon the scale upon which the final map is to be produced...

Jan 1, 1912

By C J. Pitzer

The prevention of fatal risks is a key objective for the global resources industry, especially considering poor performance with regard to fatality rate reduction and the continued occurrence of mine disasters globally. However, the industry has a credible history, over several decades, of the development and deployment management systems to control potential Serious Injury, Fatal and Catastrophic (P-SIFC) risks. While these systems have had a significant impact on the thinking and approaches to the prevention of fatal risks, fatal accident rates have not shown the desired reduction. Recent fatal and serious injury events in Australia have led to the establishment of several enquiries to further identify improvements that could be considered. Globally, fatal accident rates remain stubbornly high or plateaued in many jurisdictions, and several catastrophic events have occurred, such as tailing dams disasters in Brazil and South Africa, and the recent coalmine disaster in Turkey. Apart from the apparent lack of progress, it is evident that the deployment of critical risk systems has introduced more bureaucracy, slower response systems and additional burdens on already overloaded middle and supervisory levels of management. Organisations are rarely able to effectively tap into the risk source of risk knowledge of the frontline worker and supervisor, for various reasons discussed in this paper. To establish a valid and valuable channel of critical risk information flow from the frontline employee, Debmarine Namibia instigated the development and deployment of a system called SafeSENTRY, where the focus is on the ‘dynamic identification of dynamic risks’. This paper outlines the system, the principles of the design, the range of risk metrics that can be derived from the observations of the frontline operators, and demonstrates how a range of posited shortcomings in critical risk management is addressed how features of the High Reliability Organization (HRO) have been developed.

Mar 29, 2023

Structurally- controlled deep leaching processes have removed vast quantities of carbonate from a substantial portion of the "silica-dolomite" enclosing the 500 copper orebody. Mine drainage subsequently allowed free access of air to the porous environment created and oxidation of sulphides commenced. During the mIne development stage the exothermic and temperature-dependent nature of these hydrolysis reactions resulted in a slow general elevation of ground temperatures. and levels of 90 - lOO°C were attained in restricted moist sulphide-rich areas.With the advent of production and extensive use of explosives, the oxidation processes were locally raised to new levels of activity. Direct interaction of explosives and sulphides in favourable conditions caused temperature rises to above 260 C. Above this point the dry oxidation of sulphides in air was initiated and rapid escalation to the vicinity of 800 C has been known to occur in isolated cases.Ground reactivity is a function of the complex interrelationship of several controlling factors and no simple index exists.Control techniques are presently aimed at prevention of temperature rises in the range 100 -260 C. Inhibition of the rapid dry oxidation processes above 260 C is difllcult and current efforts have met with only partial success.

Jan 1, 1968

By R Soong

The Wharekirauponga (WKP) epithermal gold-silver deposit is located about 10 km north of Waihi in the Hauraki Goldfield east of Auckland. WKP is notable for its sheeted to stockwork quartz veins hosted in rhyolitic rocks, that have attracted exploration interest as a low grade, bulk tonnage exploration target. Exploration between 1978 and 1993 included 23 diamond drill holes totalling 5505 m. The mineralisation occurs in a rhyolite dome complex (Miocene), consisting of flow-banded rhyolite and rhyolitic pyroclastic rocks, with minor andesite. Fifty four drill core samples were collected from six exploration drill holes and analysed by semiquantitative XRD techniques. Hydrothermal alteration of the rhyolitic and andesitic rocks has developed secondary mineral assemblages of quartz, adularia, albite, chlorite, illite, sericite, interlayered illite-smectite, carbonate, halloysite and pyrite. The main zone of mineralisation is characterised by quartzadularia alteration, which grades oiItward to quartz-clay (illite, local halloysite and/or interlayered illite-smectite) alteration. Propylitic alteration is present at the southern end of the drilled area of the prospect. Depth-related changes in mineralogy include a decrease in illite and appearance and increase in quantity of chlorite with increasing depth, and the localisation of halloysite and interlayered illite-smectite in the shallow parts of some drill holes.

Jan 1, 2001

The Rate Variable Batch Test (RVBT) - A Research Method of Characterising Ore Floatability

Sep 13, 2010

By Baker G

The exposures resulting from development work, following on the discovery of a new shoot of hIgh grade ore at the north end of the Sardine tin mine, during 1952, have provided an unusual opportunity to study the oxidation of a stannite-rich ore. Through the kindness of C. C. Morton, Chief Government Geologist of Queensland, an exactly located suite of specimens representative of the exposures was supplied by J. and W. Reddie. This was later supplemented by a number of specimens culled from a parcel ofrepresentative ore submitted to the Melbourne Ore Dressing Laboratory for testing.The Sardine tin mine, near Ewan, Queensland, has been the outstanding producer of the Kangaroo Hills Mineral Field. Since its discovery in 1918, up to 1952 it has yielded about 1,500 tons of cassiterite concentrates, and about 85 tons of stannite concentrates. The outcrop ore averaged 35% tin oxide, but the grade declined with increasing depth, and by 1930 had fallen to 7% tin oxide. In the northern section of the mine the ore shoots show a downward passage to complex primary s.ulphide ore, containing cassiterite and abundant stannite.The orebodies occur in a series of fissures in a crushed zone about 50 ft. wide in slates and quartzites that have been intruded by granite (Connah, 1952). A quartz porphyry dyke forms the footwall of the original main lode in its southern part, being traced' from the surface to' the No. 4 level (173 ft. vertical depth), and two narrow dolerite dykes were encountered in the workings north of the main...

Jan 1, 1954

Geotechnical input is interwoven into the mining process at George Fisher South Mine from the planning and design of working areas to the closure of worked out areas and maintenance of life of mine and long term excavations. The methodology used consists of a mixture of application of established theoretical principles and guidelines derived from successful historical experience. In the development stage, including long term infrastructure excavations, the process takes into account the expected life of the excavation, usage and expected stress changes during its life span. On the stoping stage, the design process takes into account the local rock mass conditions, geological structure setting and previous experience in a particular orebody. Due to the high variation in age of currently used excavations, a rolling monitoring and risk assessment process for long term and life of mine excavations and infrastructure is maintained. This paper has as an output the process that must be followed to ensure an excavation on the highly dynamic mining environment at George Fisher South Mine is blasted and maintained in compliance with applicably commonly accepted safety and industry requirements.

Nov 25, 2010

Devitrification of a glassy volcanic ash equivalent to an alkaline trachyte in composition has resulted in the formation of an interstratified illite-montmorillonite with an 1:1\1 content of 1:4 as the principal clay mineral.A high concentration of potassium ions and a deficiency of magnesium ions favoured the formation of the potassium-bentonite.A poorly ordered mica mineral, equivalent to illite, was produced by weathering of potassic feldspar. Subsequent degradation of the illite through the loss of potassium was responsible for the formation of several interstratified minerals with very approximate 1:1\1 contents of 4: I as minor components.Other authigenic minerals present in small amounts were u-cristobalite, sepiolite, and the zeolite clinopitolite.The non-swelling character of the potassium-bentonite makes it economically unattractive...

Jan 1, 1967