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By R L. Brathwaite

The mesothermal quartz-scheelite lodes of the Wakamarina valley are one of twelve known mined or prospected gold-bearing areas in the Marlborough Schist. Recorded production was 556 kg gold, a little silver, and c. 390 t scheelite. 134 m of the 1800 m long Golden Bar reef are accessible in the No 2 level of the Golden Bar mine. The reef is a typical multi-banded mesothermal vein, mostly c. 1.75 m wide, enclosing narrow horses of schist country rock. Scheelite is sparsely distributed, and is more common in small veinlets in the hanging wall schist. The country rocks are textural zone I-1m schists of prehnite-pumpellyite to pumpellyite-actinolite metamorphic facies. Their geochemistry suggests they are part of the Caples Terrane, and of calc-alkaline volcanogenic arc origin. The associated Wakamarina Quartzite is strongly recumbent folded, and of the same metamorphic grade, with abundant pumpellyite, stilpnomelane, and garnet, presumably spessartine. Although it has geochemical signatures of a deep sea sediment, it is depleted in Cr and Cu, and greatly enhanced in K and Ti, when compared with a standard chert. It also has trace element characteristics of a calc-alkaline arc-related sediment. However, associated greenschist has MORB-like incompatible element chemistry. The Golden Bar reef lies within a steeply dipping, normal to transtensional dip-slip fault adjacent to a shallow-dipping mylonite shear zone, which, at least on the footwall side, is 040 m wide. The shear foliation has been severely dragged down to nearly parallel the Golden Bar reef within 1 m of the quartz lode. Preliminary structural analysis suggests that the shear zone is extensional. X-ray diffraction analyses of the wall rocks show a progressive depletion of amphibole, stilpnomelane, and pumpellyite towards the reef, and enhanced illite/muscovite and Kfeldspar adjacent to the lode, along with possible graphitic carbon within 10m. Two zones of intense quartz veining occur, one adjacent to the hanging wall for 12 m and one from 40 m outwards. Quartz vein systems in the country rock are complex and span from pre-schistosity to post-mylonite. They include multiple generations of quartz, actinolite, stilpnomelane, pumpellyite, albite, adularia, chlorites, illite/muscovite, calcite, and scheelite. Metal analyses across the Golden Bar reef showed gold values of 0.13.1 ppm, and low tungsten values, consistent with the observed sporadic scheelite occurrences. As and Sb are at background levels, but enhanced Cr (150 - 430 ppm) relative to the schists (30 - 41 ppm) suggests that the source hydrothermal fluids passed through and leached mafic to ultramafic rocks.

Jan 1, 1994

By J. Bootle

Marrow vein deposits will continue to be an important source of valuable minerals. Productivity per manshift is not keeping pace with operating costs. Increased mechanization of stoping operations must be obtained to create greater productivity at a reduced cost per ton. This application of mechanization may be to either present methods or to newly developed concepts. The total mine unit operations will be effected by increased productivity. Two approaches to increasing the mechanization of narrow vein stoping were studied with the intention of increasing stope productivity and decreasing stoping costs. A method of bringing efficient rubber-tired equipment into narrow cut and fill stopes was designed. It proposes to provide stope access by way of a ramp constructed on the stope fill. Impact breaking equipment was studied and specific applications proposed.

Jan 1, 1977

By C. Daly

The Faculty of Engineering at the University of New South Wales (UNSW) offers a core first-year engineering design and innovation course, ENGG1000, undertaken during the first and second semesters. This course is highly regarded in the sense that it provides an introduction to many concepts and activities that students will experience over the four-year minimum for which they are undergraduates at UNSW. Approximately 1400 students enrol in the semester 1 course across the Faculty, typically 80 of which undertake the Mining Engineering stream. Students in teams of between six and eight design and construct a physical model to represent an aspect of their chosen discipline. For example, in 2013 the mining engineers designed and built a model dragline. This paper concentrates a major aspect of the course ? the involvement of team members in group activities and the development of the associated skills of peer assessment and peer review as the course progresses over a period of 12 weeks. The term ?peer assessment? in this paper refers to the requirement for students to assess the design components of their peers. This course has a structured requirement in terms of how a successful design is a result of a sound design process rather than a ?try and see? approach. Each student must describe in detail the process they undertook to achieve their final design ? hence the approach is independent of the discipline and/or project selected. Peer review is a process whereby students review the contribution of their team members to the overall design. This activity encourages team involvement and interaction. The final assessment mark can be moderated by the outcome of this peer review, although it is run twice during the semester. The first ?run? is for feedback only during week six and hence no moderation is undertaken. It was found through consultation with students and from questionnaires that both processes are well accepted and highly regarded by students, as they give them a degree of ownership of the assessment process. In addition, the processes provide rapid and relevant feedback on the progress of individual students. Peer review and peer assessment are also considered to be very valuable tools for use in courses in succeeding years. For instance, many of the courses in mining engineering rely heavily on group assessment tasks.

Jan 1, 2014

By C. Daly

"The Faculty of Engineering at the University of New South Wales (UNSW) offers a core first-year engineering design and innovation course,ENGG1000, undertaken during the first and second semesters. This course is highly regarded in the sense that it provides an introduction to many concepts and activities that students will experience over the four-year minimum for which they are undergraduates at UNSW. Approximately 1400 students enrol in the semester 1 course across the Faculty, typically 80 of which undertake the Mining Engineering stream. Students in teams of between six and eight design and construct a physical model to represent an aspect of their chosen discipline. For example, in 2013 the mining engineers designed and built a model dragline. This paper concentrates a major aspect of the course - the involvement of team members in group activities and the development of the associated skills of peer assessment and peer review as the course progresses over a period of 12 weeks.The term ‘peer assessment’ in this paper refers to the requirement for students to assess the design components of their peers. This course has a structured requirement in terms of how a successful design is a result of a sound design process rather than a ‘try and see’ approach. Each student must describe in detail the process they undertook to achieve their final design - hence the approach is independent of the discipline and/or project selected.Peer review is a process whereby students review the contribution of their team members to the overall design. This activity encourages team involvement and interaction. The final assessment mark can be moderated by the outcome of this peer review, although it is run twice during the semester. The first ‘run’ is for feedback only during week six and hence no moderation is undertaken.It was found through consultation with students and from questionnaires that both processes are well accepted and highly regarded by students, as they give them a degree of ownership of the assessment process. In addition, the processes provide rapid and relevant feedback on the progress of individual students.Peer review and peer assessment are also considered to be very valuable tools for use in courses in succeeding years. For instance, many of the courses in mining engineering rely heavily on group assessment tasks."

Jan 1, 2014

By Leonard Obert

[Part I of this report3/ proposed a sonic method for determining pressure, in situ, on rock pillars, arches, and other structures. Tin r Loa required (1) a laboratory determination of the variation of the velocity of sound with pressure in samples of rock taken from mine pillars to establish a velocity pressure relationship for the type of rock, and (2) a measurement of the velocity of sound in the mine pillars from which the laboratory samples were taken. The pressure on the pillars could be determined by correlating the velocity in the pillar with the velocity-pressure relationship established in the laboratory. The success of this method depends on the extent to which velocity of sound varies with pressure. Furthermore, Young's modulus of elasticity, E, can be calculated from longitudinal velocity, V, by the relationship, E V2d .....(1) where d = density. Hence, the variation of the elastic modulus with pressure also can be determined. It pointed out that this method might be extended to assist in the prediction of rock bursts, inasmuch as the rock is subjected to extreme pressure in these instances.]

Jan 1, 1940

By Edward Jacobsen, Patrick J. Lydon

"The ongoing expansion of the Oak Creek Power Plant in Oak Creek, Wisc., includes a tunnel bored in rock that connects to four vertical intake shafts approximately 1.5 miles (2.4 km) offshore in Lake Michigan. In 2004, Case Foundation Company was awarded a lump sum contract to install these intake shafts. In spite of delays that shortened the May to September construction season by up to 50%, four shafts and liner assemblies were drilled in 2005 and 2006. The shafts were connected to the tunnel in 2007 by mining upward to reach the lower portion of each liner and then removing its internal bulkheads so that lake water fl owed into the tunnel. The project is one of the largest private construction projects ever undertaken in Wisconsin. The expansion adds 1,230 megawatts of generation. In addition to the tunnel and offshore work, there will be 16 miles (26 km) of railroad track and 6 million cubic yards (4,600,000 m3) of earth work. The 27 ft (8.2 m) diameter tunnel, drilled some 150 ft (46 m) below the surface of Lake Michigan, originates onshore at a pump house. A structural slurry wall was constructed as the foundation for the pump house. The tunnel passes to the south near the current water intake before bearing east toward the new offshore intake shafts, which are 12 ft (3.6 m) diameter by 108 ft (33 m) long steel liner assemblies. These were grouted in place from approximately 3 ft (1 m) above the crown of the intake tunnel and then to 20 ft (6 m) below the lake bottom.Site GeologyOffshore. The plant site is north of the Racine-Milwaukee county line in an area affected by glacial activity. The soil conditions encountered at each shaft location were consistent, with noticeable variations occurring in the top of rock elevations that sloped downward from the innermost to the outermost shaft."

Jan 1, 2008

By William R. Yernberg

The 2003 Rapid Excavation and Tunneling Conference (RETC) was held at the New Orleans Marriott, New Orleans, LA, June 15-18. The New Orleans conference was the 16th since the RETC was formed in 1971. This year’s conference was sponsored by the Society for Mining, Metallurgy, and Exploration, Inc.(SME), with co-sponsorship of the Construction Institute of ASCE. Attendance at the meeting was 1,178, a conference record. This was up significantly from the771 attendees at the 2001 meeting in San Diego, CA. The RETC was formed to “advance the engineering and scientific knowledge of rapid underground excavation and tunneling through interdisciplinary meetings, publications, technical-educational exhibitions and encouragement of research.” The RETC conferences are now held every other year. They provide an opportunity for individuals to meet with designers, contractors and manufacturers associated with the tunneling industry to share experiences in all phases of tunnel design and construction.

Jan 1, 2003

By J. J. Fitzpatrick

"This paper deals with the methods used by Quebec Cartier Mining Company in the evaluation and selection of new haulage equipment and in increasing the productivity of the existing fleet.Selection of new equipment is based upon the comparison, for each model under consideration, of the capital investment required and the estimated operating costs and production rate. The calculation of the production rate is based on a widely used estimating procedure. Actual operating conditions considered in the method include: payload, haul distance, road grade, rolling resistance, loading and dumping times, and operational efficiency. A digital computer is used to handle the large volume of repetitive calculations required. Where a fleet of haulage equipment includes trucks of different size and performance characteristics, the problem exists of assigning each truck type to the different working locations to minimize total cost. Linear programming can be used in the solution of this problem."

Jan 1, 1967

By Fennell B

A process for the recovery of cobalt from a speiss produced at Sulphide Corporation is presented. The speiss is leached in oxygenated sulphuric acid to dissolve the metallic iron at a pH of around 4. The resultant iron (11) is subsequently oxidized in the leaching vessel and precipitates as goethite. Acid is regenerated in the precipitation allowing dissolution of further speiss. Subsequent to the conversion of most of the iron in the speiss to goethite, conditions become sufficiently oxidizing to dissolve cobalt. Cobalt is not co-precipitated under the leaching conditions, yielding a pregnant solution containing the cobalt and some iron (11). The principal advantage of such a process is the significantly lower acid consumption over that obtained by complete dissolution followed by selective precipitation. An impure product of cobalt hydroxide can be obtained from the pregnant solution by neutralization.

Jan 1, 1983

By Jim Baumann

Deposited millions of years ago in irregular paleokarstic channels, Jamaica’s extensive bauxite deposits provide good quality ore for alumina production and subsequent aluminum smelting. Bauxite mining operations are critical to the Jamaican economy. It accounts for a large percentage of Jamaica’s export earnings. Bauxite production in Jamaica accounts for about 10% of the world’s output each year. Bauxite deposits in Jamaica lie close to the surface. They can be extracted using standard surface mining techniques. The deposits occur in scattered pockets across the country’s rugged landscape. So it was necessary for two of the country’s major mining and refining operations to implement cost effective methods for the acquisition and management of bauxite reserves and surface ownership distribution rights.

Jan 1, 2002

By James H. Owen

Because of price structure, ANFO is normally considered to be the most cost effective explosive used in quarry blasting. Results indicate that bulk smulsion can be more cost effective in applications where hole sizes range up to 6.5 inches in diameter while providing the simplicity of single product loading and storage. This can be accomplished without any fragmentation and/or movement loss usually in patterns which are about twice the size of ANFO patterns, allowing the combined drilling and blasting cost to be less when using bulk emulsions. Examples are presented supporting this concept using actual field results along with some simple calculations which take into account differences in the products such as density, matrix and detonation velocity.

Jan 1, 1998

The Peelwood district of New South Wales is located some 65 miles south of Bathutst on the Tuena-Crookwell road. A number of occurrences of lead-zinc-copper ore are known from this district but only three mines, Peelwood, Cordillera and Mt. Costigan, have achieved any significant production. The purpose of the paper is to describe the mineral composition of sulphide ores from these three localities.HISTORYNo published information on the geology of the Peelwood area is available. Came (1899) reports that, at the time of cessation of mining operations in 1888, the Peelwood mine had produced some 600 tons of copper metal and regulus, the Cordillera mine had yielded 9000 tons of ore at the recoverable grade of 2·5 per cent Pb, 2·5 per cent Cu, 90z/ton Ag and 1 dwtjto:p. Au, but that no production figures were available from Mt. Costigan. No further work was carried out on these properties until 1951 when the Electrolytic Zinc Company of Australasia instigated a programme of geological mapping and exploratory diamond drilling (Whitten, unpublished data, 1953). The Peelwood district was recently mapped by Mutton (unpublished thesis, 1960) from whom the following geological summary account was taken.GENERAL GEOLOGYAll rocks in the Peelwood area belong to a series of interbedded fine grained sediments and volcanics that are thought...

Jan 1, 1961

By Fathi Abdrabbo

Open caissons are used for many geotechnical engineering applications. Open caissons may be used as deep foundation elements bypassing weak soils to tip in firm deeper strata, and in rivers and maritime construction to reduce the risk of scour. Open caissons are also used for collecting sewage water through gravity sewer pipe networks or from sewer force mains. In such applications, the design and construction of open caissons require a detailed soil investigation program. In this way, the design and construction plan of an open caisson can be developed with full knowledge of the prevailing subsoil conditions. The engineering and construction techniques are key factors to achieve functional caissons. Based on close observations during construction stages, the current study presents some challenges that were encountered during the construction of two open caissons of internal diameters 20 m and 10 m (65.6 ft and 32.8 ft). This paper describes the procedure followed to alleviate the construction difficulties encountered. Site exploration program and control measures required to satisfy design and construction requirements are crucial aspects. Sinking of open caissons in dense or very dense sands is risky. Incorrect sinking of open caissons may cause extra cost, delay in construction, and harm to nearby structures. Air/water jetting near the cutting edge of an open caisson, outside slurry trench, and/or inside open trench may be used to drive an open caisson downward. Unsymmetrical work around an open caisson may lead to tilting of the caisson. If this occurs, the tilt should be immediately corrected before resuming the sinking process. Improper cleaning of fine materials on the caisson?s excavation bed, and/or inappropriate pouring of underwater concrete may result in a defective concrete seal. The paper contains a series of practical guidelines to assist those intending to use open caissons, and shares good caisson sinking practice with practitioners. Finally, the study aims to understand the difficulties encountered and to anticipate future problems.

Jan 1, 2012

By Mika Muinonen

"Dewatering of nickel concentrate at the INCO Thompson integrated mine-metallurgical site takes place within the smelter plant. The eight original 60 foot diameter cable torque thickeners of which four were operational and eight Dorrco internal drum filters have been replaced with a single Outokumpu high rate thickener and a single Lasta pressure filter. The modernization has resulted in a filter cake which has a more stable and lower moisture content. Control of the entire dewatering process has been improved and costs have been reduced.Typical filter cake produced from the Dorrco filters during processing of high tonnages of Birchtree mine ore was ~20% moisture vs. ~13% moisture for concentrate produced from the Thompson mine ore. The high moistures were correlated with the amount of fine magnesium silicate gangue in the concentrate. As Birchtree ore processing rates have increased, this filter cake moisture became unacceptable because of material handling problems and the impact on furnace metallurgy. The Dorrco filters were replaced with the Lasta filter in 2003 that has consistently produced filter cake at ~11% moisture.This paper summarizes the piloting, design, installation and commissioning of the modernized dewatering circuit.INTRODUCTIONThe Thompson integrated nickel processing facility was built in 1958 and originally consisted of a mine-mill-smelter and, soon after, a refinery.Nickel concentrate is pumped from the mill as a dilute slurry directly to the smelter facility ~200 meters along an unheated pipe trestle. Originally, nickel concentrate was de-watered using up to 8 conventional 60-foot diameter thickeners and 8 internal vacuum drum filters."

Jan 1, 2006

By K. L. Cashdollar, C. K. Man, J. R. Gibbins

Oxyfuel combustion is currently one of the principal technological options being considered for capturing carbon dioxide from pulverised coal power plants. In oxyfuel combustion, coal is burnt in a mixture of recycled flue gases and added oxygen instead of in air. In principle this yields a flue gas containing only carbon dioxide, water vapour and small amounts other impurities. Oxyfuel combustion is superficially similar to combustion in air, but there are inevitable differences. This paper describes ignition tests on pulverised coal suspensions using a suite of coals of different rank and from different countries of origin and over a range of oxygen and coal concentrations of interest for oxyfuel combustion. The ignition tests were carried out using the National Institute for Occupational Safety and Health (NIOSH) 20-litre explosion chamber. The purpose was to determine how easily the various coals ignite and burn in mixtures of O2 and CO2 compared to their combustion in air. The residual char volatile and ash contents for the ignition residues were measured using a thermogravimetric analyser (TGA), allowing Q factors (i.e., enhancement in apparent volatile yield due to higher heating rates and/or heterogeneous reactions) to be determined and compared. An ignition index has been derived from the explosion and char data. This index has been used to rank low volatile coals for ignition propensity in air. The results show that to obtain ignition and combustion comparable to that in air, the oxyfuel O2-CO2 gas mixture must contain over 30% O2. Keywords: CO2 capture, combustion, pyrolysis, oxyfuel.

By D Craw, J Youngson

Recent exploration for mesothermal gold deposits in the Otago Schist has focussed largely on extensions of, or analogies to, the reverse fault-hosted Hyde-Macraes Shear Zone deposit. Abundant normal fault-hosted mesothermal and epithermal vein deposits in the Otago Schist have attracted less attention, largely because they have limited lateral extent and steeper dips. Northwest-striking normal fault-hosted vein sets near Barewood and Hindon in east Otago crosscut schist foliation on the Barewood-Hindon plateau at a high angle along a combined strike length in excess of 20 kilometres. The trend of the vein sets is not linear, but rather contains several right lateral steps. Almost all veins dip steeply to the northeast. Angular discordance between schist foliation and the plateau surface along the trend increases from near zero at the northwest end of the veins to about 30¦ at the southeast end. Crude formation depth estimates decrease from about 7.5 km at the Barewood end of the zone to

Jan 1, 2002

By G. Montes-Atenas

Throughout the years, research studies have reached a consensus in acknowledging the relevancy of surface chemistry phenomena on minerals separation and metals extraction. Many techniques, and notably, scanning electron microscope-based technologies have revolutionised the entire mineral processing industry. Nevertheless, the comprehensive understanding on how surface chemistry properties influence the performance of many processes involving ores is still a challenge, a matter of controversy. The latter is mainly due to the fact that all interfacial processes do not necessarily require stoichiometric and well defined atomic structures. This is particularly true in the case of sulphide minerals which are well known to be superficially unstable in aerated media. When trying to measure any variable related to mineral-mineral or mineral-aqueous solution interfaces, there are too many unknowns regarding how sensitive the interface is when facing sampling protocols and sample handling. The aim of this research work is to make a case for improving future concentrators? survey protocols. It suggests a methodology to study effectively chemical changes at the outmost mineral surface layer at different stages of a mineral processing operation. The sampling protocol and sample handling is presented in details and it is applied to the regrinding stage of an industrial plant.

Feb 27, 2013

By Berny Rivera

The paper point out the Galvanox process developed at the University of British to leach concentrates containing copper sulfide mixtures, mainly chalcopyrite. This patented process is based primarily on the galvanic interaction between chalcopyrite and pyrite, which allows chalcopyrite to be leached preferentially over pyrite. Under the correct process conditions, near-complete extraction of copper can be reached typically within twelve hours. This study will also show that this process is suitable to treat low grade copper concentrates (bulk concentrates) taking advantage of the selectively of chalcopyrite over pyrite, and the use of pyrite as a catalyst.

Sep 9, 2007

By Stephen J. Harven

Geologic conditions in eight northern operating sections of Jane Mine, Keystone Coal Mining Complex. Armstrong County, Pennsylvania are defined by utilizing drillhole data and underground geologic mapping. Three of the eight sections are experiencing difficult mining conditions in the Shelocta "0" coal seam (formerly the Lower Freeport). The five remaining productive sections will exhaust their reserves within one year. Coordinating mine planning with future production levels is aided by indicating areas that appear favorable and lack the geologic conditions that cause difficult mining. Roof rock 1 ithologies, lithologic variations in and below the floor, jointing, overburden thickness, coal splits, paleochannels. and clay veins are the principal geologic factors believed to influence mining conditions in Jane Mine. Careful definition of each cause allows for a reasonable assessment of future mining conditions.

Jan 1, 1987

By Fun-Den Wang

This report presents the results of two large scale field coal pillar strength tests (80 ft by 80 ft), the results of a series of laboratory small core sample tests, and the correlation between those field and laboratory tests. The concept of applying laboratory coal sample strength data to predict the in situ coal pillar strength appears to be feasible. The deformation property of large pillars can be obtained successfully by testing the coal sample in the laboratory within acceptable accuracy. There are prevailing directional strength and deformation properties in coal pillars along the butt and face cleat system.

Jan 1, 1976