Search Documents

By C. F. Lee, Bezalel C. Haimson

A 300 m deep test hole at Ontario Hydro's Darlington nuclear plant site, 65 km east of Toronto, was used to determine the state of stress in the Paleozoic limestones (O-22O m depth) and the Precambrian granitic gneiss (220-300 m). The results of the hydrofracturing measurements indicated a state of high horizontal stress along the depth of boring and a consistent orientation of principal stresses in each geologic unit. These results were confirmed by a borehole TV camera survey, and by overcoring tests. The magnitudes and orientations of the measured in situ stresses were used in a feasibility study of siting an underground nuclear plant, and in particular in the geotechnical design of proposed reactor caverns in Precambrian rocks. Their implications on cavern stability under operational and accident conditions were analytically studied, taking into consideration the potential superposition of thermomechanical stresses under loss-of-coolant condition, and the possibility of thermal spalling in the host rock.

Jan 1, 1979

By H Kundapen, J J, C Rumble, S Miller

This paper describes measures taken by Ok Tedi Mining Limited (OTML) to minimise the risk of acid rock drainage (ARD) resulting from mining operations at its Mt Fubilan porphyry copper-gold mine in the remote Star Mountains of Papua New Guinea. The risk of acid generation and metal leaching as a result of oxidation of these sulfidic deposits has long been recognised by OTML. In 1998, OTML instigated the ARD Management Program to fully evaluate these risks and to formulate, if necessary, trial and implement appropriate management strategies. In implementing the ARD Management Program, OTML has adopted a risk management approach consisting of five stages: risk identification, risk analysis, risk assessment, risk treatment, and review and monitor. Significant progress has been made in relation to risk identification, analysis and assessment. The work currently underway to put in place a comprehensive risk treatment and review process will ultimately determine the success or otherwise of this approach.

Jan 1, 2003

By R. Hogg, T. F. Dumm

A simple shape description scheme has been developed which has the specific aim of distinguishing between angular and more rounded particles. The procedure involves fitting a general polygon (usually about 20 sided) to the particle profile. Geometric shape descriptors have been defined based on variations in the angles between adjacent sides and their radial displacement from the particle centroid. A two-parameter shape description, incorporating an angular variabli1ity and an elongation index, has been shown to be clearly consistent with visual observations. A single-parameter angularity index has been shown to be very sensitive to small differences in particle roundness and seems to provide a better description of angularity than other approaches such as signature and fractal analyses. The scheme has been applied to three sets of fine quartz particles produced by different grinding procedures. The results indicate that the technique is capable of distinguishing between angular and re1atively rounded particles and can quantify their specific shape features.

Jan 1, 1991

By S Strohmayr, R Harvey, A See

Ernest Henry Mining Pty Ltd started production in August 1997. The Ernest Henry orebody consists of two distinct parts, a complex supergene ore zone overlying a primary ore zone. The economic copper minerals in the supergene ore were chalcocite, bornite, secondary chalcopyrite and native copper while the primary zone has only chalcopyrite. The variability of the supergene zone made concentrator operation difficult and predicting metallurgical performance using mineralogy essential to establish the capabilities of the concentrator. A paper presented at the 1998 Mine to Mill Conference entitled Mineralogy Controlling Metallurgy at Ernest Henry Mining (Barnes, Strohmayr, Brindley and Munro, 1998) presented the testwork and initial plant surveys that showed that the mineralogy of the ore controls the metallurgy of the concentrator. This paper presents the data obtained from the subsequent years of operation treating both the supergene and primary ore types. A review of the actual supergene mineral distribution in feed and subsequent recoveries compared to those predicted as part of the flowsheet design is also presented.

Jan 1, 2003

Following the usual custom, three meetings are planned for the year. The Mid-Continent meeting will be held at Oklahoma City, Okla., Oct. 7 and 8, and the California meeting is planned for Los Angeles, probably also early in October. A program along the usual lines is under way for the annual New York meeting. Discussion and planning of the year's activity started in March. An effort is under way to secure papers dealing with some overlapping phases of engineering, petroleum geology, geophysics, law, economics, refining, etc. The main reason for attempting a program along these lines is the belief that unusually interesting technical papers can be obtained. The degree of specialization in the technical and related fields has permitted but few individuals to develop a sufficiently comprehensive viewpoint. Also, at times the developments in a particular field are capable of giving great stimulus toward much needed solutions of difficult problems in others fields of activity. With the coming of the period of restriction of production to market demand, many changes have occurred in policy and technique of petroleum production. Some changes have been advances, others have been of retrograde nature. It seems doubtful whether the adjustment to the condition of excess producing capacity has been complete or sound in some major respects. Many changes are in progress and others need to be initiated. The industry has excessive producing capacity so far as immediate market demand is concerned, but reserves for several years hence are generally believed insufficient. Exploration and discovery should go forward but development should proceed with caution and under control. Property rights should be clarified and protected for the new condition— without excessive cost for drilling wells that serve no purpose except that of giving some protection to property rights at the cost of an increased price to the consumer. Under the more steady condition of assured supply for the immediate future, as compared to the hand-to-mouth condition of wide-open production, a greatly advanced technique of development and production is possible and is being developed. Great progress has been made, but much remains to be done. Along some important lines progress can be effected only by better understanding between the engineer and the geologist, the lawyer, the politician, the geophysicist, etc. There is need

Jan 1, 1937

By D. E. Walsh, J. T. Hollow, H. K. Lin, J. L. Oleson

At the Fort Knox Mine, Fairbanks, Alaska, carbon fines are generated during stripping, acid washing and kiln regeneration operations. Because of their gold value, carbon fines are collected by a filter press. Samples of the carbon fines show that they consist of 20% to 30% carbon, 70% to 80% grit and 0.17 to 0.68 g/kg (5.0-19.9 oz/st) gold. About 80% of the gold values in the carbon fines used in this study are in the form of recrystallized free gold grains, with the balance being the adsorbed gold on the carbon. High recoveries of gold and carbon were obtained from the fines in laboratory tests using froth flotation, with a high rejection of the grit. More than 95% of gold and 90% of carbon can be recovered by three stages of gold flotation followed by two stages of carbon flotation. Key words: Gold recovery, Activated carbon, Flotation

Jan 1, 2003

By Thomas Connolly

The Homestake Mine is situated in the northern portion of the Black Hills of South Dakota in a series of steeply dipping and highly folded Precambrian Rocks. The ore bodies are localized along plunging anticlinal and synclinal folds which are locally called "ledges." The gold bearing ore is confined mainly in the Homestake formation which is an iron-magnesium carbonate series of rocks. The individual ore bodies are pipe or lense-shaped zones which plunge 30º to 75º from the horizontal. These ore bodies range from 10 to 100 feet wide and 50 to 400 feet along the strike. Gold values are erratically distributed in a gangue consisting of cummingtonite schist, sideroplesite schist, quartz, pyrrhotite, arsenopyrite, chlorite schist and ankerite. Usually the ore bodies dip at 70° to 80º and often have folded shapes like "fish hooks" or "troughs." Ore grades must be determined by extensive sampling and all mining is based on assay control.

Jan 3, 1974

The restructuring of the minerals industry has created new challenges for the design and delivery of professional development, and difficult decisions for potential participants. New technologies offer some new methods of delivery, but fall short in providing all of the benefits of face-to-face participation. This paper is intended to be a catalyst for discussion of the issues involved in delivery and participation in cost-effective, relevant and timely professional development.

Jan 1, 2000

The Green Parrot and Reward stratabound silver-lead (copper-zinc) deposits are located in the eastern part of the Arunta Block. At Green Parrot, mineralisation is contained within a north-south striking lode horizon comprised of elongate lenses of massive garnet or calcsilicate-carbonate "lode rocks" with intercalated sericite-biotite schist and laminated biotite-feldspar schist. The "lode rocks" are increasingly calcareous to the west. The mineralisation is broadly zoned with an increase in lead content and decreases in copper and silver contents from east to west. The principal sulphide minerals are galena, sphalerite and bornite. The Reward deposit lies adjacent to a lens of massive garnet "lode rock" which is contained within garnetiferous sericite-quartz schist. Primary mineralisation consists of galena, chalcopyrite, sphalerite and pyrite. Both deposits are associated with a substantial thickening of the lode horizon which is narrow and discontinuous along strike from the Green Parrot and Reward deposits.

Jan 1, 1984

By Malcolm J. McPherson, Satya Harpalani

A thorough knowledge of coal permeability and its variation with factors like stress conditions, and time, is useful in simulation studies of mine ventilation and coalbed methane recovery, as well as characterizing coalbed methane reservoirs. An experimental investigation was carried out to study the gas flow characteristics of coal to enhance the under- standing of the mechanism of methane flow through it. The work consisted of measurement of permeability of coal samples under triaxial stress and an examination of the physical structure of coal using electron microscopy. Effort was made to fit the experimental data to several phenomenological models that have been used to describe fluid flow through porous media. It was realized that gas flow through coal cannot be described by models that assume this flow to be through a bundle of capillary tubes. However, results suggest that this gas flow could be predominantly through fractures and cracks in coal, and this could be represented by flow between parallel plates.

Jan 1, 1986

The American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc, shall be composed of constituent parts as follows Section 1 Societies-The Institute shall be divided into three or more Societies as follows a The Metallurgical Society of AIME Society of Mining Engineers of AIME Society of Petroleum Engineers of AIME Other Societies may be formed within the framework of AIME or granted member¬ship in AIME as approved by the Board of Directors Section 2 Divisions and Subdivisions-The several Societies of the Institute shall consist of Divisions as follows a The Metallurgical Society of AIME 1 Institute of Metals Division 2 Iron and Steel Division 3 Extractive Metallurgy Division Any Divisions or Subdivisions which may be formed in the future with the approval of the Board of Directors Society of Mining Engineers of AIME I Coal Division 2 Industrial Minerals Division 3 Minerals Beneficiation Division 4 Mining and Exploration Division

Jan 1, 1960

By S. Kelebek, S. O. Fekete

The flotation process developed at Falconbridge laboratories utilizes sulphur dioxide and diethylenetriamine (DETA) reagent combination in the depression of pyrrhotite to allow its separation from pentlandite and chalcopyrite. DETA by itself has failed to produce flotation selectivity with samples from plant and pilot plant streams which showed relatively high redox potentials. However, DETA was found to function effectively on laboratory-generated samples under certain conditions. The results of poor depression are in keeping with thermodynamic calculations which indicate that in the presence of sufficient xanthate and DETA, the formation of ferric dihydroxy xanthate and dixanthogen is possible under oxidizing conditions. The use of sulphur dioxide alone has also resulted in a rather poor depression of pyrrhotite. However, the combined use of these reagents has resulted in an efficient and consistent separation of pyrhotite from pentlandite and chalcopyrite. Various aspects of this selective flotation system are presented along with a discussion on possible operating mechanisms.

Jan 1, 1995

By C. Y. Chen

Public Law 95-87, the Surface Mining Control and Reclamation Act of 1977 (SMCRA), Section 516 (b), requires the underground coal mining operator to "adopt measures consistent with known technology in order to prevent subsidence cawing material damage to the extent technologically and economically feasible, maximize mine stability, and maintain the value and reasonably foreseeable we of such surface lands, except in those instances where the mining technology wed requires planned subsidence in a predictable and controlled manner.. . ." Congress also directed the Secretary of the Interior to promulgate regulations to implement the law. As a result, the control of subsidence from underground coal mining to minimize surface damage has become the mandate of a federal law. This paper discusses the mechanics of subsidence and the effects of subsidence on ground features. This paper also summarizes some measures used to minimize the possibility of damage to structures as a result of subsidence due to underground coal mining.

Jan 1, 1984

By John P. Bingham

GRACE mine and mill, owned by Bethlehem-Cuba Iron Mines Co. and operated by Bethlehem Cornwall Corp., are being developed to produce 9600 tons of 42 ½ pct Fe magnetite ore, to yield 5760 tons per day of agglomerated iron concentrates averaging 65 pct Fe. Located about 14 miles south of Reading, the property is ideally situated in relation to good highways and railroad. Three major steel plants, at Bethlehem, Steelton, and Sparrows Point, Md., are about equidistant from the mine. Discovery of the orebody resulted from an airborne magnetometer survey, completed in 1948, con¬sisting of 7000 lineal miles of flight lines spaced one-fourth of a mile apart and extending from the Delaware River on the east to Gettysburg, Pa., on the west. After examining the magnetic maps, Bethlehem's geologists made limited surface traverses over the Grace mine and Warwick area to check the location, and realtors were engaged to purchase the desired properties over and adjacent to the area showing favorable indication of ore.

Jan 1, 1957

By Lynn B. Hales, Randy Ynchausti, Jeffrey D. Mckay

Many consider rougher flotation control to be more of an art than a science. Some have even thought it impossible to make process control decisions and changes without human interaction. Controlling flotation bank pulp levels to maintain consistent pulling rates in the face of changing feed slurry flow rates, varying mineral types, and inconsistent reagent additions can be daunting. However, an advanced supervisory control strategy was installed on the plant floor to control an industrial rougher flotation circuit with little or no operator interaction. Plant staff monitored the flotation circuit under supervisory control and reported benefits of up to 4% improvement in copper recovery above that achieved with an older supervisory control strategy. To accomplish this work, a novel use of instrumentation to solve a flotation bank pulp level control problem was employed, a new implementation approach was used to correct some flaws in the older approach, and careful attention was paid to a few key process control principles. This paper discusses important aspects of these activities.

Jan 1, 2000

By W. C. Lacy

A WIDE variety of metalliferous deposits in Peru shows a close and consistent relationship to intrusive and extrusive igneous rdcks. This relationship furnishes a clue to the comp(osition of ore-bearing fluids and to the timing in separation of these fluids from differentiation magma Conclusions presented here are based on ten years' study of a large number of metalliferous deposits in Peru. The most important of these areas are shown in Fig. 1. The structural relationship of meta1 mineralization to the intrusive series and of the members of the series to each other can be illustrated by three examples: I The well described Cerro de Pasco (Ref. 1, p. 160) sulfide mass shown in Fig. 2 is localized along the ' eastern contact of an agglomerate-filled crater. Quartz-monzonite porphyry and related intrusive breccias, which in places border the pyrite mass On west, are replaced by the pyrite and cut by later transverse vein structures. Late unmineralized but

Jan 1, 1958

By Edward C. Mack, Ronald G. Stovash

INTRODUCTION Ronald G. Stovash General Superintendent Consolidation Coal Company Shoemaker Mine Moundsville, West Virginia Consolidation Coal Company's Shoemaker Mine is located in West Virginia's Northern panhandle near Wheeling, adjacent to the Ohio River. Steam coal is mined from the Pittsburgh #8 seam which averages 65 in. in thickness. The 10 in. of draw rock directly above the coal is taken on advancement, but remains when longwalled. The top consists of up to 12 in. of lower quality coal, and immediately over that, up to 10 ft of multi layered shales, coal, and bone. The cover ranges from 300 to 800 ft of shales and limestone. Two longwalls operate in the mine. The first longwall started in April 1975 and is retreating its eighth panel. This wall was the first to use shield supports in the United States. The second longwall started in September 1979 and is currently retreating its first 7,000 ft panel.

Jan 1, 1981

To monitor the quantity and quality of air in underground mines to assure safe working conditions. Approach Several mine air monitoring systems, consisting of sensing stations in the return airways and control stations on the surface, have been Installed and tested. How It Works Sensor stations are located at strategic places in the underground mine. At each station, the sensors measure air velocity, air temperature, methane concentration, and carbon monoxide concentration. In one system, differential air pressure between intake air and return air, is also measured. Output voltages of the sensors are converted to digital signals at the sensor stat ion; these signals are multiplexed so that data from all sensors can be trans-phone wire to a central station. There the data are displayed and alarms are triggered when the sensed values exceed (or in the case of air velocity, fall below) a preset value. In addition to receiving data automatically, the central station can poll individual sensors at any time.

Jan 1, 1978

By Adams R. W

A commercial scale strong acid leaching plant was commissioned at the Risdon plant of the Electrolytic Zinc Company of Australasia Limited, a member of the Pasminco group of companies, in February 1988. It was designed to upgrade the lead/silver residue product from 26% to 37% lead, thus improving the realised value and increasing overall zinc recovery. This in turn enables the lead smelter treating the lead residue to improve its productivity. The equipment consists of two 250m3 bricklined leach tanks and two 6.5m diameter stainless steel high rate thickeners operating with counter current washing at 95¦C and 120 g/L H2SO4. The present filtration and drying equipment is also being replaced. Two 35m2 squeeze action filter presses equipped with horizontal plates are being installed, together with ancillary drying equipment to ensure that the final product complies with the transportable moisture limit. The new filtration plant is due to be commissioned in mid-1989.

Jan 1, 1989

By Pierre-Yves Morvan

One of the numerous challenge for underwater mining is the positioning. This paper describes an architecture for the integration of an Ultra Short BaseLine (USBL), an Acoustic Synthetic BaseLine (ASBL) operating in Sparse Array mode and a Doppler Velocity Log (DVL) closely coupled with an Inertial Navigation System (INS) for precise subsea positioning in severe environments. By using such architectures, the INS can help to reduce the noise on the measurements coming from acoustic sensors. Another advantage is the capability to reduce the number of required transponders on the seabed, and as a consequence, reduce the time for the deployment and calibration of each transponder. The paper further describes sea-trials performed to assess the ability of a complete positioning system to provide decimetric positioning precision even with a single beacon deployed in the navigation area.

Jan 1, 2017