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A 3-D computerised model of the southern part of Greymouth Coal Limited's Coal Mining Licence area has recently been completed. This model, and associated 3-D CAD tools, has/is being used to optimise drillhole spacing during exploratory data collection and as a visualisation and interpretation aid. This model will also provide the basis for future mine planning, with the emphasis on an optimal mine outline to maximise safety and profitable coal extraction. Previous use of computer techniques was restricted to drillhole database entry, storage and log production. Recently a 3-D geological/structural model was created for the Southern Rapahoe Sector of the Greymouth Coalfield. Geostatistical analysis of the database highlights the inadequacy of the present drillhole spacing for preliminary mine planning. The sparsity of hard data at depth results in a lower level of confidence in the accuracy of the 3-D model. Nevertheless, the model and 3-D CAD techniques has been used to target and refine ongoing resource evaluation, and provides the basis for initial reserves. In the future the geologic model will be used as the basis for preliminary and later (optimal) mine planning. It is also expected to accommodate other forms of data input in seam drilling and seismic. Development of the 3-D computer model was a first in the Greymouth Coalfield and highlights both the use of computerised techniques for resource evaluation and mining, and the effects of wide spaced drillhole data on model accuracy. The computer will continue to provide the most efficient and cost effective tool for optimal resource evaluation and mine planning as Greymouth Coal Limited moves from feasibility/mine planning to full production. The increased use of computer-based methods for mine planning should be seen as part of 'The Changing Face of West Coast Mining' in line with the theme of this Conference.

Jan 1, 1996

This paper sets out to discuss how alluvials - particularly mineral sands, tin and gold have adjusted to meet the problems of lower grade and more difficult physical political and economic conditions. The mineral sands industry seems to have adapted satisfactorily but less so with tin and gold.

Jan 1, 1996

By Yongbin Yang

Cathodic reduction of oxygen is a process involved in many fields. As is well known, the mechanism of oxygen reduction usually varies considerably with electrode substrates. In this paper, cathodic reduction of oxygen on gold electrode was studied by linear sweep voltammetry with regards to cyanide leaching of gold. As the results shows, the electron transfer number increases as potential shifted negatively and decreases as pH value increases. Besides, the increment of electron transfer number as a function of potential decreases when pH value increases. When pH increases to 13.0, the volt-ampere curve exhibits a relative flat section with currents approximate to the limit current density of a 2e process. By varying dissolved oxygen concentration, the electron transfer number was calculated for pH11.0 at different potentials, the results being 2.387e, 2.732e, 2.982e, and 3.227e at, -0.35V, -0.40V, -0.45V, and 0.50V, respectively. The calculated current densities are in good conformity with measured results.

Jan 1, 2010

By A. C. Wilson

In 1991, local prospector C. ?Mickey? Clement recovered at least three alluvial diamonds from the Michipicoten River. Two of these stones were sent to the Department of Mineralogy, Royal Ontario Museum, where they were identified as industrial grade diamonds with weights of 1.05 and 1.13 carats. Both stones were described as frosted and graphite-inclusion riddled. In 1995, prospector Sandor Surmacz and geologist Marcelle Hauseux discovered diamonds in bedrock approximately 20 km north of the Michipicoten River. An 18.1-kg bulk sample of a xenolith-rich lamprophyre, taken from an outcrop at the side of the Trans Canada Highway north of Wawa, yielded 1 macro diamond and 5 micro diamonds. All but one was gem quality (Sage 2000). Since then, more than 36 occurrences of diamonds in bedrock have been reported in an approximately 30 km2 area centred 20 km north of the town of Wawa. The occurrences are hosted within a sequence of unusual, Archean-aged, heterolithic breccias previously considered to have no economic significance. Ten kimberlite occurrences also have been confirmed in the Michipicoten greenstone belt in the last 5 years. Two of these kimberlites are diamondiferous. To date, expenditures on property acquisition and diamond exploration in the Wawa are estimated at $120 million (CAN). This paper summarizes the geological observations made on these occurrences and discusses including the relationship between the occurrences and the regional geology.

May 1, 2003

By Richard A. Winters

There are no producing or developing mines or active mining claims in the Deschutes Canyon RARE II study area. Only two prospects were found; they have no identified potential for mineral resources. Thin diatomite deposits occur in the Pliocene Madras Formation. Development of sand and gravel deposits in the area could not favorably compete with similar deposits in the surrounding area which are closer to points of use. By mid-1982, active oil and gas lease applications covered about 25 percent of the area, a reduction from nearly 100 percent in early 1981. No holes were drilled for oil and gas exploration. INTRODUCTION Personnel of the Bureau of Mines, Western Field Operations Center conducted a mineral investigation of the Deschutes Canyon RARE II area during the summer of 1982. The area, about 10 mi (16 km) southwest of Madras, Oregon, covers 10,890 acres (4,407 ha) in the Crooked River National Grasslands (fig. 1). The Deschutes River has incised a deep canyon into the north sloping elevated lava plain near the transitional boundary of the High Lava Plains and the Deschutes-Umatilla Plateau geomorphic divisions (Baldwin, 1964, p. 20).

Jan 1, 1983

By Zhuo Chen, Jun Zhou, Jiemin Zhou

Samples of the reacting suspension particles were taken from the reaction shaft of a commercial flash furnace at different heights. The processes of matte and slag formation and morphology of the samples in the shaft were observed and analyzed. Variations of matte and slag composition in the shaft were investigated. By analyzing the samples taken from the settler at different locations, settler processes were studied such as slag formation, agglomeration and separation of matte-slag phases, Fe3O4 reduction, copper-in-slag reduction etc. In accordance with the characteristic of matte and slag formation the flash furnace can be divided into 6 functional regions, and a mechanism model called as “Micro bath process” is proposed for matte and slag formation in a commercial flash furnace. INTRODUCTION During flash smelting, concentrate particles scattered in the reaction shaft complete their oxidation reactions in suspension. The droplets produced fall into the settler beneath with a small amount of un-melted solid particles, agglomerate and separate into matte and slag layers which are tapped out from their tap holes separately. With respect to the extent of slagging reaction in the reaction shaft, there isn’t any commonly accepted understanding in literature (Kimura, Ojima, Mori & Ishii, 1986; Kemori & Kondo et al.,1988; Kemori, Denholm & Kurokawa, 1989; Fagerlund &Jalkanen, 2000). Some assume that the slagging reaction in the shaft can be ignored and some propose that all slag is produced in the shaft. With regards to the characteristics of the physical-chemical changes of concentrate particle in the reaction shaft, although there are some research results reported from pilot scale and commercial scale experiments (Kemori, Ojima & Kondo, 1988; Hagni, Vierrether & Sohn, 1988; Jorgensen, Taylor, Dickinson & Stevenson, 1992; Swinbourne, Simak & Yazawa, 2002; Kivinen & Tuominen, 2005), they are generally limited themselves to theoretical analysis and calculations. No studies are published concerned with the processes of matte and slag generation in the shaft, quantitative analysis of the processes, variations of matte and slag composition and morphologies of the melts along the axis of the shaft, etc.

Jan 1, 2019

By Holger Witthaus

Beside the traditional geomechanical evaluation methods the geotechnical parameters are recognized as important facts of the planning work for multiple seam mining. Standards for applied monitoring and investigation methods for geotechnical determination of drill cores, laboratory rock-tests and observation of roadheadings are the basics for rock mechanics classification and support design. The geomechanical classification is in this context an essential element. The planning procedure, as it is becoming more and more detailed, beginning with the panel layout up to the technical instructions of roadway development and design of roadheading machinery, nowadays uses a lot of geotechnical information that also are expanding to include quantitative determination of more parameters. The current monitoring system includes the description of separation planes using drill cores and roadheading observation as well as laboratory tests of rock-strength and geophysical borehole examinations. This information is analyzed within the geomechanical standard-classification. The re-engineering process of comparison the predicted support success to the actual monitoring results provides the opportunity for continuous optimization of the planning work und support design. This way of empirical analysis is used for basic planning work in Germany for decades. But using the technical standard of information technology and a centralized database now it is possible to reach quick-win effects in implementing research results on the one hand and actual experiences on the other hand.

Jan 1, 2006

By P. D. R. Maltby

"With the narrow vein structure of Nova Scotia gold deposits, selective mining is rarely possible and mill heads will be too low (below 0.10 oz per ton of gold) to support a conventional mill of up to 1000 ton per day capacity at present gold prices. The recent operation of a small 100 t.p.d. mill at Cochrane Hill using fine grinding - leaching - filtration supported this assertion. Milling costs exceeded $25.00/ton of feed mainly due to high capital, labour and maintenance costs.Accordingly, since 1981, efforts have been directed towards the development of a cheap gold extraction process in terms of both capital and operating costs. The main criteria is to produce gold below US $200 per oz including all administration, mining and process stages. This paper describes such a process development for Cochrane Hill. LOCATION AND HISTORY OF THE PROPERTYThe Cochrane Hill property is located about 8 miles North of Sherbrooke, N.S. on highway No. 7. Sherbrooke is about 180 miles east of Halifax. Gold was originally discovered at Cochrane Hill in the 1860's. Early work consisted of trenching. In the 1930's a small shaft was sunk to about 80 feet and some tonnage treated using a stamp mill with gravity concentration of gold.Northumberland Mines Ltd. acquired a 70% interest in the property in 1977. Subsequent drilling indicated a potential zone of gold mineralization with a drill-indicated tonnage of one million tons having a grade of 0.07 ounces per ton of gold (all high assays cut to 1 oz) down to a depth of 300 feet recoverable by open pit mining methods. In broad terms, the goldbearing zone is about 50 feet wide and 800 feet long and dips at about 70°."

Jan 1, 1984

By Karl Nienhaus

The BGMR has developed a method for an online-analysis during drilling processes in cooperation with Fraunhofer Institute for Laser Technology in Aachen and various industrial partners. This allows for efficient utilization of deposits, maximum recovery of desired minerals and frequent and costefficient updates of deposit models. The used method, namely laser-induced breakdown spectroscopy (LIBS), was implemented into a compact demonstrator in order to analyze drill dust and loosened material within mining environments and directly on drill rigs. The consequently developed OFURanalyzer (OFUR ? online-analysis of mineral deposits) provides possibilities for exploration and visualization of deposit models in real-time and thus creates an opportunity for innovative applications, such as contactless, continuous quality control of minerals throughout the extraction process. A major challenge in the execution of this project was the necessity to develop a laser system that could withstand rough mining environments dominated by dust, shocks, vibration and therefore would be suited to operate under such conditions.

Oct 1, 2009

By Norman O. Lotter

The problem of quantifying the full performance potential of an ore body in a concentrator, and how to configure a flowsheet to achieve that potential, either for a new operation or an existing one, is a strategic challenge. Modern flowsheeting technology that has been developed over the last twenty years has provided a suitable platform to achieve this. The integrated use of geology, compositional and quantitative mineralogy, sampling models, quality controls, and mineral processing, including flotation testing, has evolved into what is now called process mineralogy. Two specific tools have been developed and validated as standard methods in this toollbox. These are statistical benchmark surveying and high-confidence flotation testing. Both of these have borrowed from the sampling theories of Pierre Gy and from geostatistics. Additionally, they work on a replicate measurement and averaging basis, thus reducing the overall random error level. With this arrangement, one is in a position to characterize the ore from true samples and identify and quantify the economic minerals present in a manner that easily brings out the processing implications and likely grades and recoveries. In particular, the approach captures the variation in the ore body, which, if properly translated into the flowsheet design, minimizes the risk that unexpected responses will develop in the concentrator operations. A further advantage is that successful plant trials are now possible and practical. An overview of this approach is presented with two case studies.

Jan 1, 2011

By F. M. McEvoy, E. J. Steadman, R. Murfin

In England, the provision of aggregate is determined by the historical relationship between construction and aggregate consumption. This approach does not necessarily lead to sustainable decision-making and can be seen as being driven by political expediency, rather than reasonable environmental consideration. The introduction of the statutory requirement for Strategic Environmental Assessment (SEA) in the UK has provided the opportunity to examine this issue on a more rational basis. This paper provides a practical application of a SEA based approach, to the provision of aggregates at a regional level. The process, underpinned by relevant information on resources and environmental assets, suggests that alternative supply scenarios for aggregate provision are tested in a transparent, consistent manner with increased genuine stakeholder consultation. It supports a move away from "predict and provide" approaches to one where aggregates are sourced with the best balance of environmental costs and benefits.

Jan 1, 2005

Assessment of the Consistency Between Different Laboratory Froth Stability Measurements

Sep 13, 2010

By S. J. Stokowski

Abstract An extensive drilling and laboratory testing program indicates that a construction aggregate resource is present within the Oligocene Sombrerito Formation limestone, southwestern Dominican Republic. The first part of the testing program included the collection, photographing and geologic logging of diamond drill cores to allow lithologic subdivision of the strata into potential quarry layers. The primary lithostratigraphic units are: I- (youngest) approximately 10 m of white, dense marine limestone II-approximately 5 m of white, interbedded dense and chalky marine limestone III-more than 2 m of tan, chalky, calcitic dolomite. Unit I is often altered by lateritic weathering and/or dolomitization. Unit II is often altered by dolomitization. The cores were individually crushed by quarry layer into coarse and fine aggregate sizes for chemical and physical analyses: specific gravity and absorption, MgSO4 soundness, sand equivalent, Atterberg limits of the minus #40 mesh fraction, and LA degradation. The unaltered portion of Unit I is suitable for all construction aggregate uses. Unit II is best suited for crushed stone base. Each of the non-weathered units decreases in coarse-aggregate yield and quality with depth and diagenetic dolomitization. Dolomitization typically causes about 5% lower yield of coarse aggregate, a sand equivalent of about 20 units below the original value an increase in absorption of about 3%, an increase in the LA of up to 13%, and a decrease in the average five-cycle MgSO4 soundness of about 17%.

Jan 1, 1991

By Calvin Konya, Anthony Konya

State and Federal construction specifications require the Blasting Contractor to prepare a Master Blasting Plan which is reviewed by the Owner’s Representative. The Master Blasting Plan requires the Contractor to submit the design of a typical blast. Most blasting specifications also require the Blasting Contractor to submit Daily Blasting Plans. The Master Blasting Plan and the Daily Blasting Plan require that the Blasting Contractor also submit the types and quantities of explosives and initiators used. The specifications also request that the Blasting Contractor submit the pounds of explosive used per delay for both production and presplit blasts. The Blasting Contractor may also be required to predict the anticipated ground vibration and air overpressure levels for the proposed blasts. There are equations that can be used to predict the ground vibration. There are also equations that can be used to predict the air overpressure levels. The data for these equations were primarily derived from quarry and surface coal mine and some construction blasts. Data from major construction projects were analyzed in this study to determine new air overpressure propagation equations for construction blasting. These new prediction equations compare calculated results analyzed from field data with other existing air overpressure prediction equations. Production blasting air overpressure values are also compared to air overpressure from presplitting

Jan 1, 2015

By S. D. D. Welsby

"A pilot-scale flotation column was used to evaluate four polyglycol frothers at Teck’s Highland Valley Copper Mine. The column was fed with flotation plant feed from the grinding circuit cyclone overflow. Frother dosage was changed by controlled addition to the column feed. Pulp, froth and metallurgical performance were assessed using gas dispersion measurements, water recovery and copper, molybdenum and gangue grades and recoveries. Ranking the frothers based on pulp and froth phase performance using gas dispersion measurements and water recovery yielded contradictory rankings. All of the frothers changed the froth structure in a similar manner such that, at the same structural conditions, they all gave the same degree of separation between water and entrained solids. The only difference between the frothers was what dosage was required to achieve a certain structure. Changes in pulp structure appeared to be related to the critical coalescence concentration (CCC) for each frother. Changes in froth structure were not completely described by the CCC and involved other factors, such as the hydrophobicity of particles in the froth. All of the frothers were capable of achieving the same metallurgical result, just at different dosages. Optimal dosages for the frothers were anywhere from the CCC, where copper and molybdenum grades were maximised, to 2 to 3 or 4 to 7 times the CCC, where copper and molybdenum recoveries, respectively, were maximised.INTRODUCTION Background Due to supply issues, Teck’s Highland Valley Copper (HVC) Mine replaced Dowfroth 250C, their auxiliary frother, with Huntsman Polyfroth W31. The primary criterion for selection was that the new frother gave the same performance as Dowfroth 250C, minimising disruption to the circuit. Frothers play a dual role in flotation, altering the bubble size in the pulp zone and the stability of the froth. A stronger or weaker frother, or a blend of both, will alter the balance between pulp and froth effects and, ultimately, metallurgy. Dowfroth 250C and Polyfroth W31 may not necessarily be the best frothers for HVC from a metallurgical standpoint. There may be a different frother or frother blend that could deliver higher recovery in the bulk roughers."

Jan 1, 2014

By K Shannon, A Shaw

The Hilton and George Fisher deposits occur 22 and 24 km north of Mount Isa, NW Qld, Australia respectively. Both deposits occur as deformed Proterozoic, sediment hosted, stratiform orebodies hosting Pb-Zn-Ag (Hilton) and Zn-Pb-Ag (George Fisher) mineralisation. The two deposits are separated by approximately 2 km of strongly faulted barren shales, mudstones and siltstones along strike. Despite this, correlations between the Hilton and George Fisher deposits have previously been assumed on the basis of textural, lithological and geochemical similarities, but previously lacked specific details to prove exact stratigraphic matches.Feasibility drilling allowed broad correlations based on the position of siltstone pillars separating individual orebodies. However the position of continuous potassium-rich, siliceous and cross-fractured tuffaceous marker beds (TMBs) often used as stratigraphic markers within the Hilton Mine were initially unrecognised within the George Fisher stratigraphy where they are erratically silicified and often not cross-fractured resulting in correlations being difficult to prove. As a more detailed knowledge of TMB locations at George Fisher was gained it was possible to look for corresponding TMBs within the Hilton orebodies. Recent underground stope definition drilling at the two locations enabled specific TMBs, stratigraphic units and even individual sedimentary beds to be matched between the two locations, despite the large separation between mines.The correlation between the two deposits has implications for future exploration drilling north of George Fisher. If a specific stratigraphic horizon can be determined within one hole, positioning of further drillholes can be more accurately planned. The significance of having stratigraphic matches between Hilton and George Fisher also has implications for correlations with other Isa Valley deposits. Convincing preliminary TM and stratigraphic correlations have already been made between George Fisher and the Isa Lead Mine 24 km to the south.

Jan 1, 2002

By J J. Batchelor, J B. Metson

Titanium (ilmenite) concentrate was extracted from a New Zealandilmeno-magnetite deposit. Tailings from the existing processing line at the Waikato North Head ironsand concentration plant were used as a raw material feed. The titanium bearing mineral extracted was defined as intergrowths of ilmenite and hematite in the size range below 150 um. The Owen-Honda equation was used to determine the conditions forilmenite/hematite magnetic separation. Three distinct regions of magnetic field strength for the mineral separation have been defined. Theoretical estimates from this calculation have been confirmed experimentally. Ilmenite concentrate was obtained using medium field magnetic andelectrostatic separation. The final material contains 40.6 - 42 per cent TiO2 and 39.1 - 39.8 per cent Fe (total). The actual yield from extraction was about seven per cent of the Zircon, leucoxene and monazite were found as byproducts of thetitanium concentration process. Preliminary experiments have shown the viability of industrial zircon benefication.

Jan 1, 2000

By G S. Lane, G D. Richmond, J Dioses

This paper discusses the methods used in the design of flotation plants, including benchscale batch and locked cycle tests and pilot plant trials. Two case studies are presented, one for the Cadia Hill Gold Mine and the other for the Hellyer copper, zinc and lead plant. These case studies present different problems with widely different target grind sizes, liberation characteristics and HellyerÆs sequential flotation circuit versus CadiaÆs æsimpleÆ copper/gold flotation circuit. They have a common theme in that pyrite forms the principal floatable concentrate diluent. Hellyer ore contains finely disseminated chalcopyrite, sphalerite, galena, and tetrahedrite. The flotation plant design was based on extensive benchscale testwork (including locked cycle tests) on drill core and many months of operation of a 30 tonne per hour æpilot plantÆ, using the old Cleveland Tin Mine process plant suitably modified for the duty. The Cadia concentrator was designed on an extensive benchscale variability testwork program, approximately a dozen locked cycle tests conducted on drill core and two weeks of continuous pilot plant trials on three separate samples obtained from an adit into the orebody. The orebody is a monzonite porphyry with disseminated chalcopyrite/bornite/pyrite of very low grade (0.17 per cent Cu, 0.73 g/t Au). Methods used to establish the appropriate flotation circuits for the treatment of the Hellyer and Cadia ores, as well as the interpretation of the testwork data, are discussed in this paper. Plant performance is reviewed in the context of predicted versus operational performance.

Jan 1, 2002

By D. S. Saxena, Jack K. Tuttle

Lack of understanding of useful applications of explosives on construction work stem primarily from the fact that explosion is commonly associated with destruction. On rock excavation and other construction works a certain quantity of explosive is harnessed to perform useful work at the source e.g. blasts to disintegrate rock. Development in rock blasting techniques, including the use of multiple-row blasting with short delay ignition, have made it impossible to excavate rocks close to or below buildings even in closely built-up areas. To permit the use of explosives on construction projects, in ways that will not damage existing structures, guidelines have been developed from careful measurements of intensity of ground vibrations. Accurate electronic instruments are now available for doing this. PLANNING AND CONTROL Blasting operations must be carefully planned and carried out to avoid discomfort to persons or damage to property. This increase in the use of rock blasting in city areas alone has led to a number of problems due to ground vibrations, air shock waves, and the psychological effect of noise. While the latter seldom if ever causes damage, it does create irritation and discomfort to persons living or working near the blasting sites. A result of this is a steady increase in the number of complaints in respect of damage to houses and other premises. Many such complaints are genuine and damage may undoubtedly be caused when incorrect blasting techniques are used.

Jan 1, 1997

By K. K. Kelley

The entropy values at 298.1° K. for the elements and inorganic compounds, on which sufficient data were available for calculation in 1931, were discussed in a previous publication (96).3 Since that time the specific beats at low' temperatures of many more inorganic substances have been determined, and considerable advances have been made in the realms of spectroscopy applicable to the determination of thermodynamic properties. Moreover, a critical study of the existing vapor-pressure data made by the author (98) furnishes entropy of vaporization results suitable for obtaining approximate values of the entropies of a number of gases from the entropies of the solids or liquids. Consequently, it appears worth while at the present time to supplement the former publication, giving the new values now obtainable and making such revision in the older values as the data warrant. The methods of calculating entropies were discussed in previous publications (96, 98) and will not be repeated here. ENTROPIES AT 298.1° K. FOR INORGANIC SUBSTANCES In the following pages, the same arrangement is followed as in the previous publication (96). All entropy values are expressed in 15° gram-calories per degree Kelvin per gram-formula mass of substance. The figures given for gases do not include the effect of nuclear spin, as is nearly universally customary at present. The estimates of accuracy in the case of the values obtained from heat-capacity data apply only to the existing measurements and to the necessary extrapolations as they are made. It is assumed usually that the substances are in such an energy condition at the lowest temperatures reached in the specific-heat measurements that the usual normal type of extrapolation may be made. No allowance is made for error in this assumption. The recent work on Gd2SO4. 8H2O and FeC13 illustrates the difficulties that may arise in obtaining the entropies of some paramagnetic substances. Also the data and calculations for such substances as CO, H20, and N20 show that the correct entropy is not obtained in all cases by indiscriminate application of the usual

Jan 1, 1936