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As the theme of this conference is æRediscover OtagoÆ it would seem appropriate to revisit the era of the gold rushes and subsequent mining industry which rapidly advanced settlement and economic prosperity for Otago, and left permanent reminders in the form of historic mining sites, many of which are now encompassed within the Otago Goldfields Park. I have been invited to give a paper at this conference on the subject of æHistoric Goldfields of Central OtagoÆ. As well as having a working involvement with historic areas through my employment with the Department of Conservation, I have a personal interest in the early goldmining industry of Central Otago as my grandfather came out from Scotland in the 1890s to help construct gold dredges on the Molyneux. My grandfather made headlines in the local paper in 1920 when he believed he saw a New Zealand otter at Island Block near Beaumont - but that's another conservation trail that I will not pursue any further today! For this paper I intend to divide my time to cover the following topics. Firstly, I would like to sketch a mental picture of the characteristics that make up the Central Otago landscape, and the general perception that early miners must have had when viewing this foreign land. Then I would like to briefly discuss the changes and the consequences in the early gold rush to Central. Finally, I would like+ to discuss the establishment of the Otago Goldfields Park, which I will illustrate with several slides.

Jan 1, 1992

By F. Mendaña

The characteristics of the igneous and metamorphic bedrock, extra-hard and abrasive, of the Guadarrama Tunnels, a bi-tube project of length 28.4 km without any intermediate attack, are first commented upon. Next, a detailed discussion is given of the most relevant aspects of the performance of the four double shield type TBMs. The experience of this leads to various recommendations to be borne in mind in future designs of TBM having to work in rock of similar characteristics.

Jan 1, 2007

By M. J. Miller, N. Ripepi, M. Karmis, J. M. Conrad

Unmineable coal seams present an opportunity to sequester carbon dioxide emissions from power plants, while enhancing the recovery of coalbed methane. Injected carbon dioxide is adsorbed and stored on the coal surface while releasing methane that can be commercially recovered. Carbon sequestration, therefore, allows the utilization of unexploited mineral resources while reducing “greenhouse” gas emissions. This paper presents the feasibility, efficiency and enhanced recovery potential of coalbed methane production using carbon dioxide sequestration in the Central Appalachian Basin. The focus of research is on geological characterization of unmineable coal seams in Central Appalachia and the corresponding carbon dioxide storage capacity. Virginia Tech and Marshall Miller & Associates, Inc. conducted this research under the Department of Energy’s Southeast Regional Carbon Sequestration Partnership program.

Jan 1, 2006

By John Vynne

Too often, a mine’s operations, including drilling, blasting, loading, hauling, crushing, processing, etc., are considered independent steps, rather then a continuous process. In fact, these are interdependent operations with each step in the process having an impact on subsequent operations. If the effectiveness of the drilling and blasting operations can be improved, they will impact the entire mining process. Some of the resulting improvements include: level benches on grade; fragmentation and diggability with the result being reduced loading times; haul cycles improvements; and the crushing and milling operations will be more efficient and less energy consumed. Thunderbird refers to this as “Drill to Mill” information cycle or process. This paper focuses on two of the technological enhancements Thunderbird has added to its drill monitors that allow the mines to impact the “Drill to Mill” concept. These enhancements are: incorporating global positioning satellites into drill monitors; and radio off-loading of data. Thunderbird is part of the Integrated Mining Systems (IMS) alliance. IMS offers the mining industry the most comprehensive line of monitoring and navigation products available today for mobile mine equipment. In addition to Thunderbird’s drill monitors and GPS systems, the product line includes: Fleet Management Systems for trucks and loaders; dragline and shovel monitors; GPS based navigation systems for shovels, dozers and other mobile equipment; and surveying systems. IMS uses common communication systems, operating systems, and hardware components in order to provide a truly Integrated Mining System.

Jan 1, 2000

By John A. Kiefer

Ground fault and overcurrent protection criteria for coal mine a.c. distribution systems were examined under a Bureau of Mines funded investigation. The report begins with a literature review which discusses relaying topics including instrument transformers, ground-fault pickup methods, static relaying, and comparison of relaying techniques. A chapter on ground-fault relaying provides recommendations for maximum and minimum pickup levels as a function of maximum ground current and power system line-to-ground capacitance. Research in the area of phase overcurrent protection has resulted in a complete set of procedural recommendations for the selection and setting of overcurrent relays and current transformers, molded-case circuit breakers, and distribution system fuses in coal mine power systems. The final chapter, which discusses relay system maintenance, introduces a unique test set which was developed by KETRON and used to test the performance of relaying systems in coal mines.

Jan 1, 1980

By R. A. Williams

The Pascua Lama Project is situated on the border of Chile and Argentina at an elevation of 4,800 m. The ore contains gold, silver and copper, and an initial milling production rate of 33,000 t/d is planned. The mineralogy of this deposit is unusual. The ore is hard and abrasive, and it contains a complex array of sulphate minerals, such as chalcanthite, jarosites and alunites. The sulphides are predominantly enargite and pyrite. A novel flowsheet has therefore been developed, which includes dry grinding and ore washing to remove and then neutralize the soluble salts, prior to flotation, cyanide leaching and Merrill-Crowe recovery of the precious metals. These metallurgical issues and challenges associated with plant design and construction in the high and remote Andes Mountains make this a particularly challenging project.

Jan 1, 2001

By Don C. White

The Vulture mine near Wickenburg, Arizona was a major gold producer from 1863 to 1942, having yielded about 11t(12.1 st) Au and 8t (8.8st) Ag. Gold occurs as coarse native metal and electrum in quartz veins and also finely dis¬seminated within a quartz monzonite sill and its silicified wall rock. The sill is semi-conformable within a Proterozoic volcaniclastic-dominated sequence, all dipping north about 35°. Early mining focused on the vein-hosted gold, particularly in the immediate hanging wall and footwall of the sill. Later efforts included some open-pit mining of the outcropping sill and adjacent altered and mineralized rock. Two sets of post-mineral faults have complicated the orebody geometry. The sill is a 350 m (1148 ft) long apophysis from a quartz mozonite stock to the west of the mine area. The stock has been dated at 85 my and contains abundant lesser gold occurrences in its core and about its margins. The Proterozoic rocks are notably lean in precious metals except where altered in proximity to the Creataceous stock and sill. Circumstances dictate an interpretation of epigenetic mineralization related to the Laramide intrusion.

Jan 1, 1990

By F. P. Haver

Primary lead is produced in the United States by the pyrometallurgical smelting of lead sulfide (galena, PbS) concentrates, which poses sulfur dioxide and lead air pollution control problems. The Federal Bureau of Mines has investigated an alternative hydrometallurgy procedure that does not generate gaseous sulfur oxides and diminishes the potential for the escape of lead into the atmosphere. The procedure involves leaching galena flotation concentrates with ferric chloride (FeC13) solution to obtain lead chloride (PbC12) and elemental sulfur as expressed by the following chemical reaction: PbS + 2FeC13 ? PbC12 + 2FeCl2 + S°. At 100° C, over 99 pct of the PbS in the concentrate is converted to PbCl2 in less than 15 min. The leach solution, composed of brine (NaCl) containing slightly more than the theoretical required amount of FeC13, dissolves the PbC12 as it is formed, leaving a residue of elemental sulfur plus gangue. High-purity PbC12 (>99.9 pct) crystallizes from the leach filtrate on cooling and is electrolyzed in a low-temperature, fused-salt cell to obtain corroding-grade metal (>99.94 pct Pb). Spent leach solution (FeC12) is regenerated for further use by reaction with the chlorine obtained in the electrolysis of lead chloride. Other values, such as Ag, Cu, Zn, and S°, are recovered by additional treatment of either the leach solution or leach residue.

Jan 1, 1976

By R M. Briggs

Kapowai Caldera Complex (KCC), located 10 km west of Tairua (eastern Coromandel Peninsula), is a late Miocene composite collapse caldera, formed during eruption of several small and large volume andesitic rhyolitic ignimbrites. Numerous epithermal Au-Ag mineral deposits and associated alteration zones at the KCC are related to caldera (rhyolite lava domes, intracaldera faults) or regional structures (faults). The main epithermal deposit exposed in the central KCC is associated with an E-W striking structural boundary fault that cuts the Welcome Jack rhyolite dome. Propylitic (calcite - chlorite) and sericitic (quartz - sericite) alteration haloes surround this deposit. Sporadic zones of sericitic alteration are also exposed within and on the margins of the Bulls Run rhyolite dome complex. Epithermal systems post-dated emplacement of these rhyolite domes, but were controlled by them. Propylitic alteration of ignimbrite in the floor of the Kapowai and Kauaeranga valleys is related to the major NE-trending Kapowai Fault which extends SW to south of Thames. Alteration along this fault pre-dates alteration associated with the rhyolite lava domes. Numerous sericitic and propylitic altered welded ignimbrite, rhyolite and andesite lava lithic fragments have been sampled from intracaldera ignimbrites, and although no direct source is known, they infer the presence of buried epithermal systems. Repeated epithermal activity at the KCC is inferred by the exposed epithermal deposits/alteration zones and the older buried geothermal systems. Silicic caldera volcanoes are considered to be critical volcanic environments for epithermal Au-Ag mineralisation in Coromandel, but are highly variable and need detailed stratigraphic, structural, petrologic, and geophysical studies to characterise them.

Jan 1, 1999

By Jerry E. Olson

In 1986, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied part of the 20,071-acre South Fork Wilderness Study Area (OR-005-033) and part of the 8,791-acre Sand Hollow Wilderness Study Area (OR-005-034) in order to evaluate their identified mineral resources. The study areas are located in Crook County, OR, about 58 air miles east from Bend. The areas studied are underlain by Tertiary- and Quaternary-age volcanic and tuffaceous sedimentary rocks. No mineral resources were identified in or adjacent to the study area. Except for common opal and agate occurrences along the northern boundary of the study areas, no mines, prospects, or mineralized zones occur within the study areas. Bentonite is periodically mined less than 1 mi southwest of the Sand Hollow study area boundary. Neither of the study areas has geothermal leases, but both areas are under lease for oil and gas.

Jan 1, 1987

By John Haviland, Richard E. Danell

"BHP Australia Coat Pty Ltd (BHPAC) operates seven large open pit coal mines in the Bowen Basin ofCentral Queensland, Australia. These mines have operated for periods ranging from 16 to 37 years. All of these mines have dipping seams to varying degrees and are facing increasing overburden removal in an effort to maintain production. To ensure the economic viability of the operations, this increased level of overburden removal must ah.0 be conducted at lower unit costs."

Jan 1, 1995

The alkaline ethylenediamine tetra-acetic acid (EDTA) leach process for extracting tungsten from scheelite (CaW04) ores has been examined for the treatment of low grade (<0.5 per cent WO,) residue dumps. The process has been considerably simplified by applying solvent extraction directly to the leach liquor.Ammonium paratungstate is thereby produced in a one step process and this obviates the need to physically recover EDTA prior to recycling. This modified process should be an economical method of tungsten extraction.

Jan 1, 1983

By D. R. Babich, E. R. Bauer

Noise-induced hearing loss (NIHL) in mine workers, especially underground coal miners, continues to be a problem in the mining industry. The recently enacted MSHA noise standard, Part 62 – Occupational Noise Exposure (Federal Register, 1999), is aimed at reducing NIHL in the mining industry. The U.S. National Institute for Occupational Safety and Health (NIOSH) is conducting a cross-sectional survey of noise sources and worker noise exposures to address NIHL in various aspects of coal mining including surface mining, coal preparation plants and underground mining. In underground bituminous coal mining, noise surveys, consisting of full-shift worker noise exposure, time-motion studies and equipment noise profiling, have been completed on longwall and continuous miner sections in six underground coal mines. The studies revealed widely varying shift-to-shift worker exposures, with workers in certain occupations routinely exposed to potentially hazardous levels of noise. A summary of these studies is reported, including worker dose, source/dose relationships and equipment noise profiles.

Since the introduction of water cooled test rings the operation of cupelling retort bullion has not alone been sImplified, but has also been the means of concentrating the bullion for the fining test in a much shorter time.The first water cooled test ring which I used was rectangular in shape, inside dimensions 5 ft. 3 in. x 2 ft. IQ in., and made of i in. mild steel plates, with a water space of 9i in. x 3t in. However, it was found that as soon as the filling commenced to wear and the litharge came in contact with the jacket, the plate was gradually affected on the lines of the wash, caused by the blast. After a while the inside steel plate went beyond the factor of safety, and was then substituted on the sides and the front of the test ring by a tin copper plate, which has stood now for the last five years without showing the least signs of wear or leakage.The test remains in use as long as the bottom is regarded as safe, and toward the end of the life of the test the litharge is allowed to work against the copper plate.

Jan 1, 1901

By H. Gurgenli

Mining companies require accurate short-term mining forecasts to meet budget targets and customer needs. Challenging mining conditions along with employee turnover and lack of standard geologic modeling and mine planning processes can result in time-consuming and inconsistent mine plans. Documentation and automation of the processes involved in mine planning, as well as proper software utilization, are critical in overcoming these challenges. This paper discusses the steps involved in achieving an optimized mine planning system to accomplish productive and cost effective operations. In addition, a case study is included to describe the process of implementing a semi-automated system whereby the geologic model and mine scheduling database are updated monthly to incorporate changes in geology in a relatively complex open-pit coal mine. This case study proves that the ability to update geologic models based on the latest information gathered from production drilling and mining activities can greatly enhance the ability to accurately predict short-term mining production.

Jan 1, 2011

By C. Nexhip, S. Sun

Critical to understanding and controlling phase mixing and separation in metallurgical processes, is the development of reliable experimental techniques to measure interfacial properties of melt systems. A series of experiments has been carried out to determine the effect of oxygen potential on the surface tension of liquid copper. Using an electromagnetic levitation method, a surface tension-oxygen chemical potential adsorption isotherm was produced for the Cu-O system at T 1400 K. The surface tension results show good agreement with the literature values e.g. within 3 per cent for pure copper. The Belton `ideal' adsorption isotherm was applied, and the following equation derived to best fit the experimental data ? =1251-77.5 1n41+ (2.79x105 . pO1/2)](mN.m Using this equation, the surface tension of copper was calculated/predicted as a function of oxygen potential at 1400 K, and showed excellent agreement with the experimental values. This confirmed that the adsorption behaviour of oxygen in liquid copper is ideal. The saturation coverage of oxygen on the surface of liquid copper was determined to be T0 = 6.65 µmoles.m,-2 corresponding to an area per adsorbed oxygen atom of ao ? 25 Å2. These values agree well with those cited in the literature, and our experimental data cover a very wide range of oxygen potential (10-5 to 10-17 atm). Keywords: levitation melting, surface tension, Cu-O alloys, oxygen potential, adsorption isotherm, surface coverage.

Jan 1, 2004

By JO Choi

Jet-grouting method is a useful technique to reinforce foundations on relatively soft or vulnerable soil layers such as fractured zone and stratum with cavities. Although jet-grouting has been widely applied to various field works, a reliable design standard has not been established yet. A number of model tests were performed to investigate end bearing behaviors of piles reinforced by jet-grouting. It was concluded that end bearing capacity was increased in proportion to uniaxial compressive strength of grout column. Based on the test results, the design criteria for the end bearing capacity were suggested.

Jan 1, 2006

KIeeman (1968) described practice in the Mount Hebbard dump concentrator, Broken Hill, N.S.W. The purpose of this note is to give data on flotation pulp chemistry in the plant for comparison with results of Woodcock and Jones (1970a, 1970b).Ten chemical parameters were measured at ten points in the circuit using the techniques of Woodcock and Jones (1970a, 1970b). Fig. 1 shows a condensed time plot of some continuous measurements in conditioner overflow and rougher feed. Fig. 2 shows average values of selected parameters at the start and end of each of the three rougher flotation stages.DISCUSSIONpH and redox potentiaIsFig. 1 shows that pH and Eh were relatively constant at the start of sulphide lead flotation. There was a fairly steady increase in pH throughout the circuit (Fig. 2), but flotation was always conducted in a slightly acid pulp in spite of the large amount of alkaline reagents added. Eh values became more positive as the pulp progressed through the circuit (Fig. 2) in accord with results elsewhere.

Jan 1, 1973

By O. W. Owings

"The handling and transportation of explosives and explosives supplies are inherently hazardous owing to their sensitiveness to impact and flame or electric arcs and sparks. Many accidents have occurred in the past during transportation of explosives, especially when they were carried by individual miners on man-trips. When electric haulage became the usual mode of transportation and shots were fired electrically, the hazards of carrying explosives and supplies on man-trips were fully realized, and in some mines all explosives were placed in one car, usually at the rear of the trip. Far-sighted managers saw the danger of this practice and provided separate trips for delivering explosives. This step was a definite advance in safety, but the latest achievement is the construction of special, rugged, nonconducting cars.Many coal-mining men have shown considerable interest in the construction of safe cars for explosives during recent months. Undoubtedly many others are interested in this phase of safety, therefore this circular is issued to give information on cars of this type now in use.Car A (fig. 1) is essentially a closed inner box separated from an outer box by an insulating lining of rubber. The double box is attached to a standard steel chassis that has spring journals and electric welding instead of certain rivets. The chassis is equipped with roller bearings. The over-all length from pin to pin is 11 feet, 9 inches; the wheel base is 54 inches, the track gage 42 inches, and the capacity eighteen 50-pound cases of permissible explosives. The box is 10 feet long, 6 feet wide, 3 feet high at the top of the arched roof, and 2 feet 9 inches at the edges. The top of the car is 46 inches above the top of the rail.The inner box is insulated from the outer box by two pieces of 1/4-inch switchboard.-insulating matting cemented together. To cover the top, two ends, two sides, and the bottom of the box requires 320 square feet of the l/4- inch matting.The walls are well-seasoned tongue-and-groove oak, 1 1/4 inches thick and 2 3/4 inches wide. A 1 1/4-inch air space is maintained by oak strips between the outer wall and the two thicknesses of 1/4-inch rubber matting. The inner box is made of 7/8-inch, well-seasoned, tongue-and groove oak fitted closely against the insulating matting. No nail, rivet, or bolt extends through the rubber insulation.The floor of the outer box is secured to the chassis by two sets of bolts through an intermediate piece of well-seasoned oak. One set of bolts is countersunk from the top of the intermediate piece of oak, and the other set is countersunk from the bottom. The countersunk portions are filled with ""insulate,"" an insulating compound. Adjacent bolts are at least 6 inches apart.The bed of the inner box is divided into six compartments by transverse strips of wood at the bottom and partitions near the roof. Each compartment accommodates three 50-pound cases of explosives. This arrangement prevents cases in adjacent compartments from touching, so that there is no possibility of end thrust of the entire load of explosives. Each inner compartment is 21 inches high, 5g inches long, and 16 1/4 inches wide. Separating strips at the floor are 3 inches wide and 1 1/4 inches thick. The outside dimensions of the 50-pound cases of explosives used are 17 1/2 inches long, 13 1/2 inches wide, and 12 1/2 inches high."

May 1, 1940

By John K. Owens, Wayne L. Howie

Mobile roof support (MRS) machines are used as roof support during pillar recovery in retreat operations in lieu of wooden posts, cribs, or hydraulic props. A Mine Safety and Health Administration-permissible load rate monitoring system was developed for the MRS by researchers at the Spokane Research Laboratory of the National Institute for Occupational Safety and Health. The system uses a dedicated embedded processor to monitor changes in pressure inside the hydraulic cylinders of the MRS through multiplexed data acquisition channels and converts these pressure changes to load rates that sequentially activate three load-rate-indicator lights mounted on the machine. Each light represents a different loading rate to alert mine personnel to dangerous conditions during pillar extraction.