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By Teuku A. R. Putra, Patrick R. Taylor

Various pyrometallurgical methods for treating copper concentrates that contain appreciable arsenic are reviewed. Various aspects of the engineering of these treatment methods are discussed. The methods discussed include: complete oxidation with arsenic fixation; selective volatilization of arsenic; acid baking, soda ash roasting, and others methods. Methods for the ultimate disposal, or marketing, of the arsenic are discussed.

Jan 1, 2014

By M. J. Little

Potgietersrust Platinums Ltd (PPRust) is Anglo Platinum?s only open pit operation. The major slope stability concern at PPRust is rapid, small-scale brittle failure on the west wall of Sandsloot open pit. In order to improve safety and mine more economically, a comprehensive slope monitoring strategy has been implemented. In the last 3 years four new state-of-the-art monitoring systems have been installed namely an ISSI microseismic monitoring system, a GeoMoS automated prism monitoring system, prismless Riegl laser scanners and a GroundProbe slope stability radar (SSR). Groundwater monitoring and visual monitoring have also been improved over the same time period. To complement the visual inspections, SiroVision digital photogrammetry is now used for predicting where future failures may occur. All these monitoring tools provide primary monitoring which is used to identify high risk areas. The SSR is then set up in that area to provide early warning of failure so evacuation can be successfully done. Fault tree analysis has proved that with this comprehensive slope monitoring strategy the geotechnical risk at PPRust is greatly reduced, allowing mining to continue safely and economically in challenging conditions.

Jan 1, 2006

By Steven E. Mischler, Jay F. Colinet

The Mine Safety and Health Administration (MSHA) promulgated a rule in 2014 that required numerous changes in compliance dust sampling requirements for coal mine operators. Two key parts of this rule were the lowering of the respirable coal mine dust standard from 2.0 mg/m3 to 1.5 mg/m3 and requiring operators of underground coal mines to use a continuous personal dust monitor (CPDM) for compliance sampling. The CPDM currently approved for compliance sampling is equipped with a display that provides miners with in-shift information on their respirable dust exposure. The goal was to provide an indication of a potential overexposure and empower the miner and mine operator to implement changes in controls and/or operating practices to prevent an overexposure from occurring.

WHEN mining and treatment first started at Broken Hill only oxidised ores were available. These ores were rich in silver and lead-the silver mainly existing as chloride and the lead as carbonate.Treatment processes aimed mainly at the recovery of silver, lead being regarded as a by-product, and its recovery, except in so far as it affected silver recovery, was of minor importance.The first ore mined was carted to Terowie and thence railed to Melbourne, being smelted by the Intercolonial Smelting and Refining Co., of Spotswood.The first parcel (50 tons) returned £7442, or £148 16s. per ton to the Broken Hill Proprietary Company.The second parcel of 1053 tons, smelted at the Day Dream smelter, returned 132,142 oz. of silver, but no record is available as to its lead content.These results obtained from two parcels showed that by smelting the ore a handsome profit could be obtained, and Mr. La Monte was engaged to erect two 30-ton Nevada water jacket blast furnaces on Block 13. These furnaces were placed in charge of Mr. P...

Jan 1, 1928

By V. Balakrishnan, A. Hewitson

"The Kudremukh Iron Ore Company Limited, a government of India enterprise, has constructed iron ore mining, crushing, handling and concentrator facilities at Kudremukh, in southwest India. Concentrate produced is pumped 65 km to dewatering, storage and ship-loading facilities which were built at the same time at the sea port of Mangalore.A computer-based distributed process control system was implemented for all operations at Kudremukh and to interface with and monitor the Mangalore plant.The control system is examined from various standpoints, beginning with a description of its architecture, method of process input/output connection, and major hardware items.Software considerations and process applications are then looked at, with a review of the integration of the computer vendor's system software with user-developed applications programming. A control example of crusher operations is provided.Following the descriptive segment is a discussion of the design considerations and decision factors involved in the implementation of such a system considering the type of process and the remote nature of the installation site. It ends with a review of actual operating experience and conclusions regarding both this system and future similar applications.ScopeThe following is a discussion of the computer-based process control system applied for the Kudremukh Iron are Company Limited's ore handling, concentrating and shipping facilities located in South India.A general description of the process and plant equipment will be followed by an examination of the control system from the points of view of hardware and signal flow, software requirements, design considerations, implementation logistics and operating experience. Conclusions will be drawn concerning this and future computer applications."

Jan 1, 1984

By M. Hesham El Naggar, Osama F. E. Drbe

"Abstract: The use of micropiles has greatly increased the last twenty years, including applications involving low capacity micropile networks, seismic retrofitting, underpinning of existing foundations and high capacity foundations for new structures. This paper presents a field study of the behaviour of single hollow core micropiles in firm to stiff lean clay. Eight micropiles were installed using hollow bars (76 mm OD and 48 mm ID) with air/water flushing technique and advanced to a depth of 5.75m: six micropiles were installed using 228 mm (9 in) drill bit and two micropiles were installed using 178 mm (7 in) drill bit. All micropiles were instrumented with linear potentiometers to measure the vertical displacement of the micropile head and vibrating wire strain gauges to measure the axial strain at three points along the micropile length. Twelve full scale tests were conducted on the eight micropiles, four monotonic compression, four cyclic compression and four tension tests. Only the results of micropiles tested under monotonic compression is presented in this paper. The full scale load tests and a comparison of the performance of the micropiles with 228 mm and 178 mm drill bit are presented and discussed in terms of load-displacement curves, bond strength and tip resistance. The results showed that the proposed values of bond strength in FHWA give a conservative design of the hollow core micropiles. The micropiles constructed with 228 mm drill bit performed marginallybetter than the micropile with 178 mm drill bit in terms of the ultimate capacity.IntroductionMicropiles have been defined in a variety of ways, but can universally be classified as small diameter (less than 300mm), bored, and grouted in place piles (FHWA, 2005; Bruce et al., 1999; and Scherer et al., 1996). They can sustain axial (compression and tension) and/or lateral loads. Dr. Fernando Lizzi used micropiles in 1952 for underpinning of historic buildings damaged during World War II (Bruce D. A., 1988). Since then, micropile applications have expanded rapidly to include underpinning for existing foundations, in situ reinforcement, and seismic retrofitting and foundations for new construction. In particular, micropiles have graduated from use in low-capacity micropile networks toapplications as single high-capacity foundation.Micropiles capacity is affected by the construction technique, which involves drilling, placing reinforcement, and placing or pressurizing the grout. For example, the drilling method influences the degree of bonding between the grout and the ground, and the placement of reinforcement and the choice of grouting method have an impact on the development of the bonding. Bruce et al. (1997) showed that grout/ground bond is most affected by the grouting method. Based on the type of pressure applied during the grouting process, micropiles are classified as follows (FHWA, 2005): Type A: grout is placed under gravity pressure only using either sand-cement mortars or neat cement grout. Type B: pressures typically in the range of 0.5 MPa to 1 MPa are applied in order to inject the neat cement grout into the drilled hole while the temporary drill casing is withdrawn. Type C: involves two-step process; neat cement grout is first placed in the hole under gravity pressure head only as in type A, and prior to the hardening of this primary grout, a similar grout is then injected via a preplaced sleeved grout pipe at a pressure of at least 1 MPa. Type D: like type C, this type is a twostep process: neat cement grout is placed in the hole under gravity pressure head only (but pressure could be applied in some cases), additional grout is injected via a sleeved grout pipe at a pressure of 2 MPa to 8 MPa once the primary grout has hardened. In some cases, a packer is used inside the sleeved pipe, enabling specific horizons to be treated. Recently, Type E micropile is proposed, which involves"

Jan 1, 2014

By David L. Borusiewicz, M. Suri Surendra

"Abstract Helical piles have been used as anchors and for supporting lightly loaded structures as a method of underpinning, etc in the past. Recently, helical piles are being used to support new structures because of their simple installation process using relatively light and mobile equipment. This paper presents the results of evaluation and design performed for the temporary support of existing piers during a bridge rehabilitation project.INTRODUCTIONThe helical screw foundation was invented and patented by Alexander Mitchell in England in 1833. He installed screw piles to support lighthouses in the tidal basins of England. Many applications in the earlier years in the USA were in North Carolina and in Florida to support lighthouses (in coastal plain deposits). A lighthouse of similar foundation design is still in use at Key Biscayne, Florida.In the USA, the helical piles were reintroduced as foundation elements for electrical transmission towers. Helical piles were also used for anchoring guys of self supported towers and as tie-backs for excavation support systems. Typically, helical piles are being used for supporting lightly loaded buildings and for underpinning buildings undergoing distress as a means of remediation. The helical piles are not commonly used in the transportation industry.HELICAL PILESHelical pile is a segmented deep foundation system with helical bearing plates welded to a central steel shaft. Load is transferred from the shaft to the soil through these bearing plates. Central steel shafts are available in either a square shaft (Type SS) or a round shaft (Type RS). The Type SS series are available in 38 mm to 57 mm square sizes. The Type RS series are available in 73 mm to 114 mm diameter sizes. Type SS-RS combinations are also available for compression applications in soil conditions where dense/hard soils must be penetrated with softer/loose soils above the bearing strata.The leading segment consists of a shaft with one or more helical plates that are welded to the shaft. The plates vary in diameter from 203 mm to 355.5 mm and have a thickness of 9.5 mm or 13.7 mm. Typically the plate diameter increases from the bottom of the shaft upward. A helical bearing plate or helix is one pitch of a screw thread. All helices, regardless of their diameter, have a standard 76 mm pitch. Being a true helical shape, the helices do not auger into the soil but rather screw into it with minimal soil disturbance. Helical plates are generally spaced a distance of two to three times the diameter of the plate directly below in order for them to function independently as individual bearing elements. A typical detail of helical pile is shown on Figure 1."

Jan 1, 2014

By David C. Chang

A survey of in-situ methods for determining bulk electric properties of coal is given. Largely because of the strong dependence of coals properties on operating frequency, different sensing methods have to be adopted for different applications. Evaluation of both established and feasible methods is made in this report from the viewpoint of physical set-up, probing depth, and the type of inversion involved.

Jan 1, 1977

By John Nagy

To facilitate increase in the rate of coal production the Bureau of Mines conducted a study several years ago, on the basis of which the allowable charge limit for permissible explosives in single-hole blasting was raised from 1.5 to 3.0 pounds. Further demands for accelerated production led to consideration of multiple blasting in coal, a practice that is deemed hazardous and is not permitted by most States in this country. In multiple blasting, 10 to 20 pounds of explosive or more may be detonated in a coal face within a fraction of a second, which might result in blown-out or blown-through shots with possible ignition of gas or coal dust. As experimental evidence was lacking, in January 1949 an investigation was undertaken in the Experimental coal mine at Bruceton, Pa., principally to study and compare with single blasting the condi-tions under which simultaneous multiple blasting and particularly multiple short-delay blasting may be practiced without danger of igniting gas or coal dust in mines. The first report on this subject was presented at the last international conference of mine safety research. Since that time numerous additional experiments have been made; because of other pressing problems the work has been brought temporarily at least to a conclusion. This paper is the second report on the problem. It does not contain a detailed description of all test conditions and test arrangements, many of which were described 2 years ago in part 1 (now available as Report of Investigations 4868), but the conclusions are based on the entire study. A more complete review, which will incorporate data from the entire investigation, is being prepared as a Bureau of Mines bulletin. Up to the present time, short-delay blasting of coal in commercial mines has been introduced only experimentally in Washington and in a few mines elsewhere. If the system is adopted more generally, new problems may arise, and the study may have to be reopened.

Jan 1, 1952

By Y. Luo

A PC based computer model has been developed by the authors for predicting the surface subsidence due to underground coal mining. Its reliability, comprehensiveness and user friendliness demonstrate that it is a good tool for the mine operators, government agencies and scientific researchers alike.

Jan 1, 1989

By Parker A. J, Muir D. M

Solutions of acetonitrile in water dissolve water soluble copper(I) chloride. Removal of volatile acetonitrile from the resulting solutions, by distillation with low grade steam, precipitates pure copper(I) chloride. This is used to purify a crude copper chloride sublimate from the chlorination of nickel matte but is applicable to other sources of copper(I) chloride. The pure product can be converted to pure copper(I) oxide, copper(II) oxychloride or pure copper metal directly.

Jan 1, 1980

Stope support systems, typically consisting of props and packs, are used extensively in the gold and platinum mining industry to stabilize the rock mass in the excavation vicinity and to reduce the hazard associated with rockfalls and rockbursts. The design of stope support systems was historically based predominantly on past experience and practices, and cost considerations. The recent development of a new and improved support design methodology, has led to the potential for significant increases in worker safety and support cost savings. This paper reviews some of the fundamental rock mass and support criteria that form the basis of the improved support design methodology. The considered design criteria are the height of potential fall; quasi-static stope closure rates; dynamic stope closure rates; compressive hangingwall stresses; discontinuity spacing, orientation and interface properties; effect of support length (stoping width); effect of compression rate; consistency of support performance; a real coverage; support spacing; and zone of support influence. The proposed support design methodology combines both the zone of influence and key block stability theories, resulting in optimized support systems for rockfall and rockburst conditions. The site-specific methodology consists of two stages: (i) a tributary area analysis, and (ii) a zone of support influence and a stability analysis, considering hangingwall failure due to buckling, shear and block rotation, which gives maximum safe spacing of individual support units. The methodology is suitable for designing support systems for both blocky hangingwalls and hangingwalls fragmented by face-parallel extension and shear fractures.

Jan 1, 2001

By G. M. Kintz

"Methods and costs of rock-dusting bituminous coal mines have been discussed in various publications by the United States Bureau of Mines and others.3 This paper discusses the present methods and cost of dusting at the Swastika mine of the St. Louis, Rocky Mountain and Pacific Co., Raton, N. M.In the Swastika mine the recommendations of the United States Bureau of Mines with regard to rock-dusting are followed at least as well as in any mine in the States of Wyoming, Colorado, and New Mexico. This mine is located at Swastika, N. M., approximately 4 miles west of the town of Raton and is in the Raton coal seam. The mine is rated as gassy and produces approximately 1,000 tons of coal per day.A mining system known as the ""room-and-pillar with cut-offs"" is used which results in recovery of nearly 100 per cent of the coal. The mine employs approximately 250 men.Ventilation is maintained by a Sirocco fan so arranged that the air current may be reversed and exhausting approximately 130,000 cubic feet of air per minute at 3 inches water gauge. This fan is supplemented by two auxiliary fans for emergency use. Three main entries penetrate the hill in a straight line for approximately 8,000 feet. The haulage is through the center entry, which is also used as the intake in conjunction with a two-compartment concrete-lined shaft located at the end of the entries. The main return for 3,000 feet inby the fan is 12 feet wide and 7 feet high. For this distance the ribs have been reinforced by a wall made of coke-breeze blocks plastered over with cement. Solid concrete blocks are used for the top row of blocks of the wall. Steel 10-inch I-beams spaced 40 inches apart center to center are supported on these solid blocks and thus support the roof. The next 1,000 feet inby has the same area, but the cement blocks extend to the roof, as no crosspieces are needed. The airways are kept clean and well rock-dusted.A rather unique system is used to handle gas feeders along the intake and haulage entries. There these feeders occur in the roof or where gas is apt to collect in high points along the haulage, tin funnels as large as 3 feet in diameter are placed near the roof. From these a 2-inch or other suitable-sized pipe is run into the return through the wall of the nearest break-through. A valve on this pipe line controls the amount of air pulled. These devices keep the high places clear of any gas, even when strong feeders are encountered.Fifteen-ton electric trolley locomotives are used on the main haulage and approximately 30 roller-bearing oars, each having a capacity of approximately 3,000 pounds of coal, compose a trip. All loaded tripe carry steel drags on the last car, and automatic derails are located at advantageous points throughout the mine.All loaded trips are thoroughly sprinkled on the sectional partings and at the main parting. The track is sprinkled every idle day, or if needed, every day; from a large tank mounted on a truck hauled by a motor. Neither nozzle nor spray is used, as these were unsatisfactory. The water leaves the tank. through a 11/2-inch valve and is permitted to flow on the road through a horizontal 11/2-inch T. Water is obtained from filling stations located throughout the mine. It is stated by the officials that the use of this method of sprinkling permits the entire haulage roadbed to be wetted down in two hours."

Mar 1, 1930

The effect of rare earth element Y (0-2.0at.%) on the microstructure of TiAl alloys at the as cast and rapidly solidified conditions has been investigated. The results show that the addition of Y greatly refined the microstructure of TiAl alloys at both conditions. The refinement is more significantly with higher Y content. The refinement of Y in the cast alloys is attributed to that the strip-shaped Y-rich phase locating on the grain boundaries impedes the grain growth during solidification. In the rapidly solidified alloys, Y-rich phase dispersing uniformly as spherical particles in the matrix acts as heterogeneous nucleation sites which increases the nucleation rate of ??phase during the ????phase transformation, and produces a refined initial microstructure during solidification. Higher cooling rate restricts the grain growth during subsequent cooling.

Jan 1, 2010

Copper, zinc, lead, and silver in the discordant magmatic-hydrothermal orebody of the Conrad Mine, N.S.W., all have a relatively high mean abundance. Any single concordant sulphide orebody containing the same metals has a similar order of mean abundance of only one or two of these, particularly copper, copper and zinc, or zinc and lead.The relative abundances of the metals in the Conrad orebody vary more widely than in concordant orebodies, and the lead-zinc-silver and copper-zinc-lead relationships are significantly different.INTRODUCTIONIn previous investigations of metal abundances in sulphide ores, the basis of selection of the orebodies was their form, and to some extent their geological setting, rather than hypotheses concerning their origin. In all cases they were generally concordant with the bedding of the sedimentary or meta-sedimentary rocks enclosing them, and most occurred in volcanic-sedimentary sequences. Their mineralogies were simple, and they were copper, copper-zinc, zinc or lead-zinc rich in composition. Most were of the type ascribed by several authors to exhalative-sedimentary processes.In one of these investigations (Stanton, 1958), it was pointed out that since the metals in ores of this type showed similar abundance patterns and behaviour, it would clearly be of interest to examine, and to compare with them, orthomagmatic and vein types, unquestionably derived from their igneous rock associates.The present investigation is concerned with a single orebody, of clearly discordant type, and of indisputable hydrothermal origin. The abundance and behaviour of copper, zinc, lead, and silver have been determined and compared to similar data fOl!' the concordant type. Such a comparison tests the possibility that metal abundance patterns of base metal ores may be indicative of the mode of ore deposition.

Jan 1, 1963

By L. M. Amaratunga, G. G. Hein, D. N. Yaschyshyn

Fine tailings produced in the milling process have traditionally been disposed of in tailings ponds. Attempts have been made to use these fine tailings in backfill, however, to date the majority of backfill operations have utilized only a small percentage of fines. The remaining fines are, therefore, being sent to tailings ponds creating a waste disposal and environmental problem. This disposal practice is even more acute in the gold milling industry where fine grinding, required for value liberation, results in the production of large quantities of fine tailings, of which a large percentage cannot be used in backfill. Through Cold-Bond Tailings Agglomeration (CBTA), these fine tailings can be agglomerated into pellets which can then be used as a coarse aggregate in back-fill. This paper presents the results of using these pellets to create an Agglomerated Tailings Paste Fill (ATPF) made entirely of fine gold mill tailings and cementing binders. Through this process, supplementary imported aggregates such as sand, gravel, rock-chips are not required while still maintaining adequate back fill strength. By using this CBTA technology, fine tailings are diverted from tailings ponds and becomes utilized as a value added resource in the form of aggregates for use in paste fill.

Jan 1, 1997

By Donald F. Reed

In the latter half of 1948 the Bureau of Mines investigated the Magnet Cove Rutile Co.'s prerty in northern Hot Spring County, Ark. This work was supplemental to the work done by the Bureau on the same property in 1945.2/ It was undertaken for the purpose of investigating the extent of the ore body toward the south and west and at depth and to obtain representative samples of the ore for metallurgical tests. For the latter purpose, the samples were so taken as to minimize alteration of the physical characteristics of the ore, these characteristics being determining factors in working out processes of bencficiation. During the investigation, 27 holes were drilled, 10 with a diamond-coro drill end 17 with churn-drill rigs using a Baker standard cable-tool core barrel. Drilling developed an extension of the ore deposit westward from the previously mined area but did not disclose the full depth of mineralization. Metallurgical tests to determine methods of beneficiating the ore and utilizing the resultant products are now in progress.

Dec 1, 1949

By V. C. Kelessidis

The interaction between rock and drill bit during drilling has been modeled for many years, but a complete understanding of the phenomena occurring has yet to materialize. Successful models will allow the prediction of rate of penetration in a given environment and optimal selection of drill bit and drilling parameters, thus minimizing exploration costs. In most rock-drilling models the value of the unconfined compressive strength of the rock (UCS) is used in the predictive equations, within the concept of specific energy, and the value of UCS is the percentage of the value of the stress applied on the drilling bit in order for the bit to advance. While the exact percentage depends on the model used and it is not known with certainty, good knowledge of UCS is nevertheless required before any decent prediction can be made on rate of penetration. Determination of UCS, normally done via destructive testing, requires not only the availability of sound rock core samples but also expensive testing and significant time for the test, which frequently are not available for routine drillability predictions. Hence, a multitude of methods and techniques has been proposed for estimating UCS from various indirect and/or non-destructive measurements, or combination of measurements with neural networks, such as point load index, block punch index, unit weight, and apparent porosity, water absorption by weight, sonic velocity, and Schmidt hardness. The many proposed approaches are critically reviewed and the results are compared, and what becomes apparent is that after many years, not only in mining but also in oil-well drilling, accurate indirect determination of UCS is still an elusive goal. An equation to predict UCS from sonic velocity data is suggested based on several data sets reported in the literature. Use of the specific energy equation with UCS or sonic data and utilization of drilling data allows an estimation of the efficiency of energy transfer from the bit to the rock and of the friction coefficient. Analysis of data reported in the literature, both from laboratory and field studies, has shown that this approach is sound and enables the determination of energy transfer efficiencies and friction coefficients, which for the cases studied range between 15 and 30% and 0.15 and 0.30 respectively. Thus, the suggested data analysis approach allows drillers to focus on inefficiencies and optimize drilling practices in future campaigns. Keywords Rock drillability, unconfined compressive strength, prediction.

Jan 1, 2011

By Pound J. R

THIS mine, which is the property of the S. and M. Syndicate, London, is located at Moina, in North-West Tasmania, 18 miles from Stavertorr railway station and 36 miles from Devonport. There are metalled roads from both of these places, and, althoughhilly, these are good for team or motor traffic. Mails and passengers are provided for by a tri-weekly coach service from Sheffield, a railway town, distant 23 miles. The Moina mining field is situated on a main spur between the Forth and Iris Rivers, andat an elevation ranging from about 500 ft. above sea-level at the Forth River to 2400 ft. at the All Nations mine. The elevation at the mine office of the S. and M. mine is 1900 ft. The average annual rainfall, as recorded for the past eight years, is. 68 in.This inclildes, however, a couple of years during which the rainfall was much above normal, and taken over a longer period 60 in. would be nearer the average.

Jan 1, 1919

Phase equilibria have been determined experimentally for pseudo-ternary sections of the form ?MnO?-(CaO+MgO)-(SiO2+Al2O3) with a fixed Al2O3/SiO2 weight ratio of 0.17 and MgO/CaO weight ratios of 0.25 and 0.17 respectively for temperatures in the range 1473-1673 K. The primary phase fields present for the MgO/CaO weight ratio of 0.17 include manganosite (Mn,Mg,Ca)O; dicalcium silicate a-2(Ca,Mg,Mn)O?SiO2; merwinite 3CaO·(Mg,Mn)O·2SiO2; wollastonite [(Ca,Mg,Mn)O?SiO2]; diopside [(CaO,MgO,MnO,Al2O3)?SiO2]; tridymite (SiO2); tephroite [2(Mn,Mg)O?SiO2]; rhodonite [(Mn,Mg)O?SiO2] and melilite [2CaO?(MgO,MnO,Al2O3)?2(SiO2,Al2O3)]. For the section with MgO/CaO weight ratio of 0.25 the anorthite phase (CaO·Al2O3·2SiO2) is also present. The liquidus temperatures of ferro- and silico-manganese smelting slags have been determined. The liquidus temperatures at low MnO concentrations are shown to be principally dependent on the modified basicity weight ratio (CaO+MgO)/(SiO2+Al2O3).

Jan 1, 2004