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By X. Cui

Hydrocyclone is widely used in closed-circuit grinding process. However, in the first classification operation of coarse particles with high pulp density, the shortcomings of traditional cyclone are that the grinding cycle load is much high, the apex of cyclone is easily to be blocked and classification efficiency is less. Specifically, the problems of traditional cyclone used in grinding process are as follows: (1) Mill utilization factor is low and its handling capacity is small. (2) Coarse particles mixing in cyclone overflow affects the following separation process and fine particles mixing in underflow causes over-grinding, which affects the total recovery rate of valuable minerals. (3) High grinding cycle load leads to large amount of high-density slurry pumping, which causes high energy consumption and severe wear of cyclones, pipelines and pumps. The applications of new type pre-classification hydrocyclone with centrifugal volute in the first classification process of Iron Mine Mill are introduced in the paper. Pulp particles fed in the centrifugal volute were arranged in advance, so that coarse particles can be far away from the overflow pipe, which can reduce the short circuit current to avoid coarse particles entering overflow and improve classification efficiency and accuracy of cyclone. The strong points of the new cyclone in the coarse classification operation are as follows: (1) finer overflow and less fine particles mixing in underflow improves classification efficiency more than 10%; (2) lower ball mill load cycle improves ball capacity more than 10%;(3) grinding energy consumption reduces by more than 20% and cyclone feed pump reduces energy consumption by more than 12%. In short, new type pre-classification cyclone with centrifugal volute solves the problems of fine particles mixing in underflow, high grinding cycle load and less classification efficiency in the coarse classification operation. Therefore, it has broad application prospects in ferrous metal and non-ferrous metal ore dressing plant.

Sep 1, 2012

There is growing acknowledgement that successful organisations, including mining companies, achieve their competitive advantage by better managing their employees, customers and other stakeholders. The fact that I have been asked to address this conference is perhaps evidence of the recognition of the importance of ensuring the improved management capabilities of the personnel within Australian mining companies. As many of you will be aware, prior to my appointment to the role of President of Minera Alumbrera Limited (MAA), the operator of the Bajo de la Alumbrera project, my career had been more generally focussed on industrial relations and human resources management. My appointment was met by surprise in some quarters, as it is unusual for a person without the technical background of a mining discipline to manage a world-class mining operation. However, it was recognised early in the life of the Alumbrera project that the operation did not lack technical expertise or a committed workforce; rather what was required was innovative management of the project and its operational resources, particularly given that we were operating with totally ægreenÆ workforce in a country without a large-scale mining culture. It is my experience that a particular shortcoming of mining companies is that they have tended to ægrowÆ managers based on their technical expertise rather than people management skills. Historically, many companies have assumed, or at least hoped, that their better technical people would develop the requisite skills to take on the challenges of management. Such philosophy has not always met with success. Whilst the topic for my presentation was originally published as People in the Mining Industry, within the context of the overall theme for this plenary session, People: Education for the Future, it is a subject with an extraordinary breadth of possibilities for discussion. Therefore, I have chosen to redefine my presentation to People Management Issues in Offshore Mining Projects,an issue which I consider to be an important area within the overall topic and one which has particular currency given the increased tendency by Australian miners towards offshore exploration. It is also relevant from the perspective of continued rationalisation of our industry, the recognition that there will be more large-scale, global corporate mining entities and that significantly more mining professionals will become æcitizens of the worldÆ. We therefore need to prepare our future leaders for these challenges. The topic also allows me to highlight the importance of an holistic management approach as the establishment of a new project in a foreign environment puts into stark relief the need for the application of the full range of competencies, rather than the narrow ætechnicalÆ approach to doing business. I hasten to add, however, that the mining industry is not alone in this regard and I was interested to read an article in the Weekend Australian of 22/23 January 2000, which reported on the first key speech of former Westpac CEO, Bob Joss, as Dean of the Stanford University Graduate School of Business. He said: à We know that when our students go out into the world, if they have to struggle, it will not be because theyÆre not smart enough, or they donÆt have enough good ideas. It will be because they struggle over managing themselves and their relationships to other people. The article then went on to say that Bob Joss foreshadowed an initiative to build alliances between the Business School and other Humanities departments within Stanford University to draw on their learning. Other business schools have also recognised this need, albeit somewhat late in the day, as have the most enlightened of modern corporations; in summary, successful businesses have recognised that in an age where competitive advantage through, for example, technological breakthroughs is very short-lived, it is the quality of management that will provide the leading edge. By using the Alumbrera project as a case study, I will identify certain of the challenges with which companies and individuals may be confronted in the establishment of a greenfields project outside Australia. However, many of the issues raised will have direct application in the context of the development of an Australian operation. My objective is to provide an indication of areas which should be considered at the formative stages of a projectÆs development, with particular focus on the issues of people management. I would expect that such a study would be of benefit to companies, education institutions and individuals in preparing themselves for similar experiences.

Jan 1, 2000

By J. G. Davis, P. C. Thakur

Hazardous methane gas in coal mining is receiving increased attention due to the increased US demand for coal which has resulted in the exploitation of deeper seams and the utilization of more productive equipment. Problems posed by methane emission has the Mining Research Division of Continental Oil Co. (Conoco) accelerating efforts that began in the early 1950's with Consolidation Coal Co. (Consol).1 The program's focus is on finding new techniques for degasification of virgin areas as well as control of methane in gob areas.

Jan 10, 1977

By G P. F Chitombo

The dilution of blasted ore with cemented backfill materials has been recognised as a significant factor influencing the economics of some underground metalliferous mining operations. Several mechanisms have been identified as possible causes of fill failures. The purpose of this study was to determine the possibility of damage as the result of one mechanism, that of production blasting adjacent to bodies of cemented hydraulic fill (CHF). A vibration amplitude transfer function has been developed to model the transmission of blast vibrations from the source, through ore, across the ore to CHF interface and into the CHF mass. The model may be applied in the near field. The model has permitted estimation of vibration amplitude at a point in a CHF mass, to which damage criteria may be applied. A number of assumptions and simplifications have been made to render the problem relatively tractable. Ore and CHF material characteristics recorded by a number of authors were utilised to formulate preliminary damage estimations. A simple application of the amplitude transfer model indicated that a zone of plastically deformed CHF would be produced, and would extend to a distance of approximately 0.5 metres from the interface into the CHF. A sensitivity analysis was also conducted, that indicated that the zone of plastic deformation would be more extensive given appropriate conditions. Recommendations for further model development and future laboratory and field investigations have been made.

Jan 1, 1998

By A. W. Khair, S. S. Peng

Discussion by J. Parker Gentlemen; Rainy day in Upper Michigan, a good time to catch up on reading. Am doing that, and have a couple of questions concerning the K and P paper on roof problems and supports. I wonder if the authors can enlighten me. The compressive strength of the coal was reported as 4.4 MPa (633 psi) and compressive stresses measured in the coal seam were reported at around 27.6 and 48.2 MPa(4000 and 7000psi ). Can such a soft coal actually contain such a high level of stress? Can it be measured as if the material were elastic, or does the coal behave plastically? Can that stress level be confirmed with hydraulic load cells? And if the coal is so soft, and if it is plastic, why is the stress field not hydrostatic'? The intact roofrock appears to be unusually strong, with compressive strength reported at around 145 MPa (21,000 psi), and some failures were noted as soon as the rock was exposed. Were tests run to find out how that rock responded to the addition of moisture, from sprays or from humid air? Did moisture weaken the rock? Did it cause the rock to expand quickly, thus to induce internal compressive stress? How can the near-vertical cutters, as shown in the photographs, be attributed to primarily horizontal stresses? Did the cutters follow any particular pattern in the development panels, which might be related to a particular stress pattern? For example, did they always appear alongside the stiffest pillar? Or always along the northwest rib? Was there any evidence of the pillars and entries "rotating" under the influence of differential horizontal stresses? How much did the entries and pillars rotate as the longwall face approached and passed? After rooffalls, did the openings assume shapes which would indicate a preferred shape in that stressfield and geology? Did crosscuts always survive without damage, as shown in the sketch?

Jan 1, 1992

By Harold W. Lipper

BUREAU OF MINES helium plants produced a. record-breaking 477 million cubic feet of this essential element in 1959. The supply of helium was less than the demand before operations were resumed at the Navajo plant in July and begun Sit a. new plant at Keyes, Okla., in August. Helium was in abundant supply after August, and the informal allocation system which had been in use intermittently since 1955 was discontinued Delivery of 26 new tank cars in August and September increased the total in the tank-car pool to 163. Defense and space agencies and the Atomic Energy Commission continued to use more helium in their operations and research.

Jan 1, 1960

By Grace NC, Lightfoot BW

Small scale trials of the smelting of a copper concentrate in the Sirosmelt submerged lance reactor are described. Pellets of concentrate were dropped into the reactor while injecting air-rich mixtures of oil and air through a lance into a bath of matte overlain by slag. This produced a discardable slag and a matte which was converted in sequential stages in the same reactor to white metal and blister copper. Difficulties were encountered in determining the end points of the converting stages but control techniques were developed to allow successful operations producing blister copper. Deportments of minor constituents of the concentrate to slag, matte,metal and fume for the three stages are reported and possible applications are Discussed.

Jan 1, 1980

By R. J. Anderson, A. V. Castelli

In 1986, United States' barite production fell 48.9%, consumption - sold or used by grinding plants - was off 47.3%, and imports were down 63.8%. Meanwhile, world mine production decreased 29.6%, according to the US Bureau of Mines. However, value of US-produced barite FOB mine increased 46.51%, according to USBM figures. The declared value CIF US port of all imported unground barite decreased from $41.94/t ($46.23 per st) to $39.02/t ($43.01 per st). Nevada continued to be the leading US producer of barite with 69% of the total. It is followed by Georgia, Missouri, Tennessee, and California. The USBM estimates that 65% of the barite mined was used as a weighting agent in drilling fluids. The remaining 35% was used in the production of barium chemicals and as a filler. Most of the production from Missouri, Georgia, and Tennessee was used in the non-oilfield sector. This sector made up a larger percentage of the US produced barite in 1987 than it did in 1986, increasing the overall value per ton of barite. Barite consumption was at its lowest since 1963. It is estimated that 80% of the barite was consumed in the drilling fluid market. The remaining 20% was used in barium chemicals, glass, and as filler in plastics and paper. The decline of barite used in drilling fluid followed the decline in the average number rotary rigs operating - 964 versus 1968 in 1985. This was the lowest average number of rotary rigs operating since 1971. The non-oilfield market was up 5.3% in 1986. This increase can be attributed to the increased use as a filler in plastics. Imports of crude barite, though down nearly two-thirds, still made up 65% of the barite consumed in the US. China was the leading exporter to the US with 58%, followed by India, 15.4%; Morocco, 11%; Thailand, 5.4%; Mexico, 4.6%; Chile, 3.9%; and Ireland, 1.7%. Less than 1% of the imported ore was used in the nonoilfield sector. Imports of ground barite dropped from 64.4 kt (71,000 st) to 19.8 kt (21,800 st) in 1986. Of this amount, 14.1 kt (15,500 st) were used in drilling fluids in 1986 and the remainder for non-oilfield use. During 1986, more of the grinding plants supplying the drilling fluid market were closed. Dresser Magcobar and IMCO Services, a Halliburton company, formed M-I Drilling Fluids Co. Mine production in the US will probably decrease in 1987 due to the lower cost of imported ore. No significant change is expected in the drilling fluid market. The average number of operating rotary rigs is estimated at 950 in 1987 versus 965 in 1986. The nondrilling fluid markets (chemicals, glass, and filler) will follow the overall US economy. Bauxite and alumina R. J. Anderson, Ohio State University US bauxite production in 1986 dropped to a pre-World War II level, continuing a decline that began a decade ago. 1986 production totaled 450 kt (496,000 st), compared to 674 kt (743,000 st) in 1985. World production of bauxite also decreased in 1986. This reflected the soft market in alumina, aluminum, and related products. Total mine production worldwide came to 79 Mt (87 million st), down from 85 Mt (94 million st) in 1985. For the sixteenth consecutive year, Australian production of bauxite led all other sources. No other country approached the 28 Mt (31 million st) mined in Australia in 1986, despite a 4.4-Mt (4.9-million st) drop in its output from 1985. Other major producers in 1986 were: Guinea 11 Mt (12 million st), Brazil, 6.5 Mt (7 million st), Jamaica, 6.5 Mt (7 million st), and Suriname 2.8 Mt (3 million st). Despite weakness in world demand for bauxite, Venezuela, heretofore an alumina producer, is now pushing development of a new mining venture near the western border of the state of Bolivar. Plans call for barging bauxite down the Orinoco River to the Ciudad Guyana alumina plant, a distance of 650 km (400 miles).

Jan 5, 1987

By Robert Hunt

(New York Meeting, February, 1913.) I HAVE frequently stated that while the chemical composition of steel is important, yet even greater importance is connected with the mechanical and heat treatment of the metal. During the past year I encountered such a positive example of that fact that I deem it worth putting upon record. A prominent railway system divided an order for open-hearth steel rails between two steel works, both of which are under the control of the one corporation; giving to one about 18,000 tons, and to the other 7,500 tons of the same section and to be made under the same specifications. The rolling results obtained in the two mills varied so widely that a study of the figures is intensely interesting and serves to illustrate the advantages obtained by careful ingot casting, and, quite as pertinently, the possible benefits of careful subsequent heating and rolling with moderate reductions in the rolling process. The smaller order was rolled complete in four installments during the same months that the larger order was being made in six separate installments; but, to permit of exact comparisons, the totals of the four installments (completing the order with the mill which I will call A) are given with the totals of the first four installments of the larger order, made by the mill designated as B. These rolling results are:

Jan 5, 1913

By William A. Hoffman

In This Chapter [MSHA regulations for coal mines MSHA regulations for metal/nonmetal mines OSHA regulations for tunnel construction Types of respirators used in mines and tunnels Filter materials and filter efficiencies Donning, seal checking, and maintenance Filter service life and Respirator information resources] In many cases, engineering controls are not adequate to achieve satisfactory dust levels, so respirators must be used. This chapter explains the Federal regulations governing the use of dust respirators in mines and tunnels and describes the most common dust respirators used. Filter materials and filter efficiencies for respirators are discussed. This chapter also gives some guide-lines for respirator use and recommends sources for more dust respirator information. Respirator effectiveness in reducing dust exposure usually exceeds the effectiveness of most engineering control methods. RESPIRATOR REGULATIONS [Different regulations govern respirator use in coal mines, metal/nonmetal mines, and tunnels under construction.] Coal mines under Mine Safety and Health Administration (MSHA) jurisdiction. Coal mine operators are required to meet dust standards using only engineering control methods. Typical engineering control methods include ventilation and water sprays. Respirators are not regarded as an engineering control method, so respirators cannot be used in lieu of engineering controls.

Jan 6, 2003

In November 1999 Waihi Gold Mining Company commissioned its new crushing and conveying plant used to transport both ore and waste from the Martha Mine to its ore processing plant and also its tailings dam construction area. To date, a record monthly throughput of 854 000 tonnes throughput has been achieved. This paper outlines the measures taken subsequent to the commissioning of the system to achieve greater than design throughput and to mitigate the environmental and safety issues associated with operating the system in the middle of a town.

Jan 1, 2001

By Leon Maday, Dan L. Pecha, Jeremy Johnson, Daniel N. Adams

The Brightwater conveyance system includes 26 km of tunnels, a 130 mgd pump station, 2 km of micro tunnels, and a 2.4 km outfall. The tunnels extend from Woodinville to Puget Sound through varying soils in 1 to 7 bars of hydrostatic pressure and depths to 185 m. The tunnel diameters range from 4 to 6 m and include numerous lining systems. This paper highlights major shaft and tunnel design, including dual cellshafts, multiple pipe configuration tunnels, polymer concrete segments, and the use of a one pass lining designed to convey high pressure effluent.

Jan 1, 2005

Table B-1. Summary of respirable coal mine dust samples collected under 30 CFR 90 by MSHA inspectors for underground occupations, 1988-92* [ ]

Jan 1, 1997

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 S. A. Diatchkov

There is a misconception that mineral-project economic evaluations in the former Soviet Union are either nonexistent or very limited. This is not the case. In fact, there are at least two basic methods that can be utilized to evaluate the vast mineral resources of the Commonwealth of Independent States (CIS). Evaluation procedures are based either on a comparison to known projects, which may rely on limited available data, or on potential-profit calculations, which generally uses more extensive databases. Significant philosophical differences between these systems and those utilized in the Western world include the following: •Under the centralized-government system, the economic evaluation of a mineral project was based on artificially determined mineral prices and costs. Every ten to 12 years, prices for concentrates and metals were established by the Council of Ministers and remained unchanged until the next reconsideration of prices .

Jan 1, 1995

The perennial challenge facing mining and minerals operators is to improve productivity, usually by a combination of cost reduction and performance improvement. In a typical production situation involving mining and processing activities, the standard approach has long been to seek improvements in each activity, effectively in isolation from each other. However, the realisation is growing that there is considerable potential to achieve really substantial productivity gains by much improved integration of mining and processing with the key being to consider what is best in the total sense. Some of the linkages between fragmentation in mining and downstream processing are considered in this paper. These linkages involve technical, operational and economic Considerations.

Jan 1, 1997

By Amyn S. Dahya, David J. King

"The object of the paper is to discuss the developments in Carbon-In-Pulp (C.I.P.) technology for gold recovery. The CIP process is comprised of four major operations:(a) adsorption of precious metals onto activated carbon;(b) elution (stripping) of precious metals from the loaded carbon;(c) electrowinning of the precious metals from the concentrated eluate;(d) regeneration of the eluted carbon before recycle to the adsorption process.A detailed review of the technological developments in each of the above operations is presented together with a brief theoretical background of the underlying processes. The advantages and disadvantages of the CIP process are discussed in comparison with conventional zinc precipitation. IntroductionThe carbon-in-pulp (CIP) process involves the use of activated carbon for treatment of pulps containing dissolved precious metals, and provide s an alternative to the conventional gold recover y processes using filtration or counter-current decantation in conjunction with the Merrill-Crowe zinc precipitation process. The commercial application o f the CIP process in gold processing technology is a fairly recent development and it is of growing importance around the world.The fact that activated carbon ha s the property of adsorbing precious metals from solution was first published in 1847. In the following years , a great deal of work was carried out to develop an over-all recover y process using carbon, but all attempts were uneconomical because the loaded carbon had to be smelted to recover the gold.It was not until 1950 that Zadra, at the United States Bureau of Mines Research Centre in Reno, Nevada, developed a technique for stripping the loaded carbon using sodium sulphite-sodium hydroxide mixtures and then recovering the gold from the stripping solution by electrolysis. However, this process was not effective for stripping silver and further testwork was carried out on alternative stripping techniques. In 1952, Zadra published a paper describing the use of a hot sodium hydroxide- sodium cyanide stripping technique, which was effective in stripping both gold and silver. This paper included a description and flowsheet for the CIP process which is essentially the same as we know it today. This technique was used in the first major CIP plant, constructed and commissioned in 1973 by Hornestake Gold Mining Company. Since then there have been numerous CIP plants built in the U.S A., South Africa and Australia."

Jan 1, 1983

By S. H. Yi, J. R. Kim, Y. S. Lee

The viscosities of CaO-SiO2-Al2O3-MgO-FeO slags were measured under conditions ofCaO/SiO2=1.15–1.6, 10–13 percent Al2O3, 5–10 percent MgO and 5–20 percent FeO. Slag viscosity decreased with increasing FeO content at a fixed basicity (CaO/SiO2) of slag. Slag viscosity at low FeO (<7.5 percent FeO) exhibited a minimum value by increasing MgO content in slag. Viscosity decreased with increasing slag basicity up to 1.3 while it increased as slag basicity increased from 1.3 to 1.5. Thus, it was proposed that the driving force for the decreases of slag viscosity would be an increase in depolymerization of silicate network at C/S=1.3, while the viscous behaviour at C/S>1.3 would be increased with increasing the chemical potential of primary solid phase e.g. dicalcium silicate. A thermodynamic approach for the activity of primary solid phase in molten slags resulted in a reasonable relationship between viscosity and slag components. Therefore, it was confirmed that slag viscosity in basic slags system (C/S>1.3) could be determined by the chemical potential of dicalcium silicate. Keywords: viscosity, basicity, bosh slag, blast furnace, slag structure, FT-IR

Jan 1, 2004

By Xavier B. Starnes

"SUMMARYThe J. D. Price property is in Crittenden County, Ky., about 5-1/2 miles west of Marion. The Levias-Crittenden Springs fault system traverses the property. Mines on 3 miles of the same fault system immediately northeast have produced about 250,000 tons of fluorspar ore. The Keystone property, adjacent on the northeast, has produced about 150,000 tons of ore. 3/About 1934, lessees, sank a shaft upon the Price property to a depth of 111.5 feet and crosscut from the bottom of the shaft to the principal fault. No ore was found. Later, in 1942-43, they explored the same fault by core-drilling, but this project also was unsuccessful in finding ore.The author visited the property in September 1944, and subsequently the Bureau further explored the property by core-drilling three holes. No ore was found.ACKNOWLEGMENTSIn its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. This ex¬ploratory project was under the general supervision of E. D. Gardner, regional engineer of the Central Region, and 0. M. Bishop, district engineer, Bureau of Mines. The mining branch is under the direction of L. B. Moon. The work on the project was under the direct supervision of Xavier B. Starnes, mining engineer."

Jun 1, 1947

By C. C. RAE

The Texas Panhandle produced 18,677,000 bbl. of oil in 1932 as against 25,064,000 in 1931. The decline was caused by smaller market demand, since the Railroad Commission potential increased from 105,528 to 149,260 bbl. during the year. Well Completions, 1932 The development during 1932 compares with 1931&apos; as follows: Year Wells Drilled Dry Holes Gas Wells Oil Wells Initial Pro- duction, Bbl. 1931 200 6 77 117 347 1932 136 18 28 90 603 Crude oil prices, small market demand, and lower allowable rate of production caused less drilling. Expiration of leases was one reason for a greater number of dry holes through forced drilling of questionable areas. The small number of gas wells reflected the influence of the business depression upon industrial and domestic gas demand, together with difficulties of franchise negotiations or pipe line extensions under present conditions. Probably much of the gas-well drilling was done on expiration leases, or to protect against drainage, and equalize withdrawals as between the various units held by each gas pipe line company. The increase in average initial daily production was due chiefly to excellent granite wash wells in the LeFors district developed by the Texas Co. and Skelly Oil Company. In the Panhandle district, comprising a major anticline with almost a million productive gas acres, the pools tend to merge in time, the development being confined to more productive areas. Hence separation into pools becomes a matter of time of development with some effort to keep dolomite, archosic and granite wash production separate. Many pools, like the Finley and Bowers, have mainly one type, but many leases and even individual wells produce from two zones. The oil production is usually closely associated with sea level, where proper porous formations

Jan 1, 1933