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By Sandra Penttinen

There are several ways to get a positive reaction from neighbors to blasting projects. When you need to enter structures to conduct a pre-blast inspection, the impression you make on the structure owner must be positive from the very start. Public relations with neighbors is the key. The purpose of all communications with persons residing near planned blasting operations is to educate structure owners as to what will take place during the blasting operations, to explain that safe blasting practices will be followed and vibration and airblast limits will be imposed to protect surrounding structures from damage. Once access into the structure is obtained, the structure owner can be shown, by careful documentation, all existing cracks and defects in the structure prior to blasting and construction. The objective of your visit and all communications is get your foot into the door and win the confidence of the structure owner so that he or she understands blasting will not compromise the structure.

Jan 1, 2006

By M. Magnelöv, Du Sichen, U. Sjöström

An experimental study has been performed to investigate the behaviour and separation of inclusions at the interface between steel and slag. The study has been limited to liquid inclusions because they can be a potential problem in transient situations such as ladle changes in continuous casting of steel. Model experiments with water and silicon oils have been carried out to study the kinetics of separation of simulated inclusions at an interface. The properties of the inclusions and the slags have been varied by using different oils with different viscosities, densities and surface tensions. The effect of temperature of the liquids has also been examined. Measurements of the terminal velocity, rest time and the behaviour of the liquid inclusions at the interface have been recorded using a video camera. It has been found that the inclusions reach their terminal velocity early in the vessel and the experimental velocities differ somewhat from the values evaluated using ?intermediate law?. The results from the experiments have shown that the size of the inclusions has no appreciable influence on the rest time. Droplets of AK50 oil have been found to have considerably long rest time. A water film surrounding the droplet has been expected to be the main reason for the long rest time. The present study has also shown that the viscosity of the oil has certain effect on the rest time, but only to some extent, since viscosity has double functions. A higher viscosity provides higher resistance to the droplet entering the oil phase leading to longer rest time and at the same time damps the lateral movement of the droplet along the interface, leading to easier stabilization and shorter rest time. On the other hand, a high viscosity of the oil phase results in slow dissolution process. It has been concluded that a meaningful model of inclusion separation at the metal-slag interface must take the interfacial phenomena into consideration. Keywords: Inclusions, terminal velocity, rest time, dissolution.

Jan 1, 2004

By G. C. Lammers

The object of this study was to determine the economic feasibility of hydraulically transporting Sandow (Tex.) lignite 100 miles and dewatering and thermally drying the transported lignite to a surface-dry condition. The most important factors involved in the feasibility of hydraulic transport, are the degradation incurred during transit, the length of the line, and the cost of alternative methods of shipment. In pipeline tests in which roughly 75 miles of hydraulic transport was simulated the percentage of minus-325-mesh solids increased from about 1 to 41 percent for both lignite and bituminous coal; in the micron sizes the coal fared considerably better than the lignite. Such degradation, even though it enhances flow through the pipe-line, severely aggravates the dewatering problem on lignite. Cost studies indicated that continuous vacuum filters offer the most economical means of dewatering minus-1/8-inch material. Surface moisture, if high, must be removed by relatively expensive thermal drying.

Jan 1, 1958

Cessation of mining on the Bendigo goldfield makes it evident that, as the older generation fades away, knowledge of the famous Bendigo saddle reefs will be limited in the future by their written records. It is important therefore that the summarised account by D. E. Thomas (1953) in the Geology of Australian Ore Deposits should not be misleading. Fig. 6 in this article is stated to portray a cross section and longitudinal section through a series of gold shoots in the Garden Gully 300 ft. reef. The gold shoot along the capof the saddle reef is represented as extending down the east leg in a series of prongs, with the tips of the prongs about 50 ft. apart. It is the purpose of this note to indicate that this illustration can be suspected to be a diagram of the old stopes instead of a diagram of the distribution of gold in the quartz.The original sketches of Figs. 6 and 7 in Thomas' account were extracted, I believe, from the field note books of H. S. Whitelaw, years after his death in the late twenties. Whitelaw was stationed in the Bendigo office of the Geological Survey of Victoria, carrying out geological surveys of the Bendigo mines. He was there for many years before the Gold Research committee started its investigations in 1916 and he was acutely aware of the problem attached to the distribution of gold in the reefs. He had felt concern that manyauriferous reefs were being mined without adequate study and record and he decided, as he expressed it to me, to pick up what he could as he went along. There can be little doubt that the diagrams of Figs. 6 and 7 are products of this resolve.Opportunities to investigate gold occurrences at Bendigo were limited before 1916 because the field was operated by Manuscript received at The Institute 18th November, 1960.

Jan 1, 1961

It's long been suspected that there has been an increase in the incidence of premature failure of rock bolts in underground coal mines over the past ten years. As far back as 2002 a study found a possible contributor to such premature failure in some Australian coal mines might be linked to stress corrosion cracking (SCC) (Crosky et al, 2002). That study suggested the low impact toughness could be a major influence on the susceptibility to SCC of different steel compositions. A subsequent study involving laboratory corrosion tests however failed to confirm any link with metallurgical factors (Villalba and Atrens, 2007), a finding that is at odds with field experience. Some mine sites today are still reporting prematurely failed rock bolts to the rock bolt manufacturers; the failures are being identified at SCC induced. To this end a research project has recently been commissioned at University of New South Wales (UNSW), which aims to identify the environmental factors causing SCC, through field test sites and simulating the conditions within an accelerated corrosion laboratory. This paper outlines the methodology that will be used in this study.

Nov 25, 2010

By Elmer Stewart, Richard May

"The Central Mukur deposit was discovered by the Semipalatinsk Geological Exploration Expedition (GEE) during detailed searches from 1977 to 1980. Andas Altyn Ltd., a Kazakhstanian gold mining company acquired the property and commenced mining in 1995. In 1998, Andas-Altyn Ltd. became a wholly owned subsidiary of Eurasia Gold Corporation.The Central Mukur gold project covers a linear series of parallel, discontinuous zones of near surface oxide gold mineralization that covers a distance of 7 kilometers and extends past the property boundaries. The oxide gold mineralization is a result of the regional oxidization of a primary sulfide gold mineralization emplaced in a series of shallow dipping thrust faults. Resources as calculated by the GEE are 3.45 mt at an average grade of 1.84 gmt Au in the C1 +C2 category and 7.52 mt at an average grade of 1.80 gmt Au in the P1 category. The Central Mukur Gold Heap Leach Mine consists of an open pit, heap leach pads, and an ion exchange resin gold recovery plant. Limited gold production (<2,500 ounces/year) has been achieved over the past three years leaching run of mine oxide gold mineralization. Gold recovery utiling cyanide to dissolve the Au and ionic resin technology to recover the Au for the leachate is approximately 60%. Loaded resin is shipped to a treatment plant at Almaty where the gold is stripped from the resin, refined and sold.This paper will describe the geology, mining, and processing of the Central Mukur ore. In addition, it will describe what it is like doing business in Kazakhstan and the transition from a Soviet style operation to a more western style operation.INTRODUCTIONThe Central Mukur Mine is owned and operated by Andas-Altyn Ltd. a Kazakhstanian gold mining company located in northeast Kazakhstan. Andas-Altyn is a wholly owned subsidiary of Eurasia Gold Corp., a Canadian public company listed on the Alberta Stock Exchange. The Central Mukur mine consists of a small open pit, and a heap leach operation that utilizes ion exchange resin to recover gold from pregnant solutions. In addition to the Central Mukur mine, Eurasia also owns the Myaly heap leach gold project which is also operated by Andas- Altyn Ltd."

Jan 1, 1999

By M. SIDDARAJU, Rameshwar Sah, T. Umadevi, K. S. SRIDHARA, B. D. Ganesh Shetty, M. RAJU

The production of high strength iron ore sinter for blast furnace iron making unit was developed by optimizing the granulometry of less than − 0.150 mm fines in sinter base mix which consists of iron ore fines (− 10 mm size with 0.150 mm: 41%), beneficiation plant jig concentrate, i.e., washed ore (− 3 + 0.150 mm size with − 0.150 mm 3 to 9%), beneficiation plant concentrate (− 0.150 mm size 97%), limestone, dolomite, coke breeze, lime, sinter return fines, direct reduced iron (DRI plant) fines, and micropellets produced from steel plant waste. The sintering process consists of preparation of base mix, mixing, and production of nodules using mixing and nodulizing drum by maintaining the optimum moisture, transferring of nodules to the sintering machine, and firing of sinter by applying optimum suction pressure. To optimize the < 0.150 mm fines in sinter base mix, the − 10-mm size iron ore fines was replaced with washed ore. The size analysis, granulation index (G index), and optimization of moisture w.r.t. sinter bed permeability were carried out by varying the washed ore addition from 0 to 55% in sinter base mix to vary the − 0.150 mm fine size. With decrease in washed ore addition from 55 to 0% in sinter base mix the finer fraction, i.e., − 0.150 mm in sinter base mix increased from 9.4 to 26.7%. Granulation (G) index increased from 1.46 to 3.10, sinter bed permeability increased from 33 to 53 Japanese Permeability Unit (JPU), and balling index increased from 1.4 to 3.0. With increase in − 0.150 mm fines in the sinter base mix from 9.4 to 26.7%, the sinter tumbler index (T.I) increased and sinter reduction degradation index (RDI) decreased. Increase in sinter strength and decrease in sinter RDI was due to increase in formation of Silico ferrite of calcium and aluminium (SFCA) phase and decrease in pore phase. The SFCA is the main bonding phase in iron ore sinter, and it provides strength to sinter. Sinter base mix with − 0.150 mm fines 18.9% (washed ore addition 25%) achieved desired sinter properties with moisture 8.0%, G index 2.44, balling index 2.3, and sinter bed permeability > 45JPU. Decreased the sinter properties with washed ore addition in sinter base mix beyond 25% due to decrease in − 0.150 mm fines in sinter base mix. Further, to improve the sinter properties with washed ore 30 to 45%, 3 to 10% beneficiation plant concentrate, i.e., − 0.150 mm fines was added to maintain the 18.9% of − 0.150 mm fines in sinter base mix. From the laboratory sintering studies, it was found that minimum 18.9% (range from 18.9 to 26.7%) − 0.150 mm fines should be maintained in the sinter base mix to achieve desired sinter properties.

Oct 16, 2021

By S. S. Rowland

Good afternoon, ladies and gentlemen. It is a pleasure, for several reasons, to be here at this 13th International Conference on Ground Control in Mining. Of course it&apos;s always a pleasure to be able to see and reacquaint myself with many long-time friends; but it&apos;s also a pleasure, or 1 should say worthwhile, because I take something back with me, some knowledge about mining that lets me do my job better and more safely. if I can do that, I&apos;ve accomplished my purpose in being at a conference such as this. This conference is a little different, though. I have to earn my stay. I have to earn it by telling you a story; a story about mining through a mile of rock to get from one coal seam to the same seam on the other side of an ancient river channel; a story about mine personnel taking over the job from a contractor; a story about having to mine through two faults after the hard part was supposed to be over, but, most importantly, it&apos;s a story about how it was accomplished successfully and safely by a group of ordinary coal miners possessed with determination, belief in themselves, and a "can do" attitude. If you can take any part of my story and use it to do your job better and more safely, then I will have accomplished my purpose in being here today. Kerr-McGee Coal Corporation&apos;s Galatia Mine is located in Southern Illinois near the town of Harrisburg in Saline County, about 350 miles south of Chicago and 120 miles southeast of St. Louis. Construction of the mine began in 1982, and the first coal was shipped in 1984 from the Harrisburg No. 5 Seam, 550&apos; below the surface. Mining began in the Herrin No. 6 Seam, 100&apos; above the No. 5 Seam, on April 1, 1985. Mining in both seams began by using the room-and-pillar method. In 1989, the No. 6 Seam was converted to longwall mining, as was the No. 5 Seam in 1992. Today, all mining is done by the longwall method except for the required development work, which is performed by continuous miners. A heavy-media preparation plant with a 4.2 million-ton annual clean-coal capacity processes the coal. By the end of 1994, with annual production now exceeding 4 million tons, we will have shipped over 30 million tons of steam and metallurgical coal throughout the United States and the world. Most of the coal has been used as the primary source of fuel to generate electricity for the city of St. Louis. The No. 5 Seam coal can be used as a semi-soft coking coal or as a high-Btu, relatively low-sulfur steam coal. Its use allows utilities to comply with Phase I of the Clean Air Act Amendments of 1990 without installing flue gas desulfurization units or blending with other coals. The Herrin No. 6 Seam is a high-Btu, medium-sulfur steam coal that requires blending to meet Phase I requirements. Because the No, 6 Seam coal does not meet the Clean Air Act Amendments&apos; Phase I compliance standards, we were forced to cease mining operations in the No. 6 Seam, leaving 170,000,000 tons of minable coal in the ground. Last month the Galatia Mine became a single-seam operation mining the Harrisburg No. 5 Seam only. The Clean Air Act Amendments of 1990 and the resultant S02 emission limitations on electrical power generation plants effectively eliminate, beginning in 1995, the near-term potential for profitable mining of the Galatia Mine&apos;s high sulfur Herrin No. 6 Seam coal. Because of the Clean Air Act Amendments, it is virtually impossible to market high-sulfur coals like the No. 6 coal unless the mine location and mining conditions enable greatly depressed sales prices to cover costs. We, along with the majority of

Jan 1, 1994

By John Dasher

The analyses reported on in this paper indicate that there are hydrometallurgical routes from sulphide concentrates to copper that are potentially competitive with smelters which are not permitted to emit sulphur oxides. The various hydrometallurgical processes, and their economics, are discussed.

Jan 1, 1973

By J. M. Jimenez, G. D. Schena, A. J. Cazorla

A full-scale Deister column was operated in parallel with the conventional cleaning bank of cells and a pilot Jameson cell in parallel with the conventional rougher cells. Flotation column performance was appreciably enhanced by use of an improved washing system and an internal launder. The performance of the rougher bank of cells, Jameson cells, cleaner cell bank and column were described by simple linear functions. These allowed calculation of overall circuit recoveries and evaluation of alternative circuits. An evaluation procedure based on a financial criterion is demonstrated with a simplified example, illustrating how revenues and operating margins are often of more concern than concentrate grade and recovery

Jun 18, 1905

By Darcey Baker

Quarry Blasting is usually boring, and that is how we like it. By this, boring means routine, straightforward, meat and potatoes blasting. Quarries typically will not utilize cast blasting, coyote tunnels, or any of the other more spectacular blasting techniques – just plain, old day-in and day-out quarry production and possibly overburden blasting. Differences in material characteristics, mining method, equipment availability, and target markets all play a part in determining the blasting procedures employed at any given location. However, variables exist everywhere and with foresight and planning, effects of tangible variables can be minimized. Variables caused by geology, weather, neighbors, or limitations caused by major plant or mobile equipment are, generally speaking, intangible; and leave the operator with finite options to improve or modify blasting procedures.

Jan 1, 2009

By J. S. Coats, G. E. Patts, N. Hughes

Conventional sampling methods are known to suffer from the variable loss of fine gold by elutriation. Freeze sampling yields representative and quantitative data that, when combined with information on the sedimentology of gravel-bed rivers, may facilitate the development of improved dispersion models for source detection. It is suggested that freeze sampling may have particular application to the orientation stage of a large gold exploration survey

Jan 1, 1991

By G. Tranell, L. Kolbeinsen, S. Gaal, J. Safarian

The effect of carbon material properties on the rate of MnO reduction from ferromanganese slag by solid graphite was investigated. A sessile drop technique was used to study the reduction rate of a synthetic slag containing 45 wt% MnO at 1500 and 1600 ºC. Different types of graphite substrates were used and the con-tact angle between slag droplets and substrate were measured in-situ. Moreover, the slag droplet volume during the interaction with the graphite substrates was calculated and normalised. The mathematical relationship between the slag density during the reduction and the normalised slag droplet volumes during the reduction were derived and the MnO reduction curves were then calculated. A method for measuring the slag reactivity of solid carbon was defined and used to qualify the propensity of the different graphites to react with the liquid slag. Some supplementary studies such as manganese evaporation measurement and EPMA analysis for determining the extent of MnO reduction were also carried out. It was observed that there is nota significant difference in the wetting angle of the graphite substrates by the slag, and the wetting is not changed within the temperature range of 1500-1600ºC. However, the changes in the contact angle during the slag reduction at 1600ºC are more than at 1500ºC. The kinetics of MnO reduction is dependent on the type of graphite and it is more dependent on the graphite properties at lower temperatures. On the other hand, the dominant properties of graphite on the reduction rate vary with temperature. A multivariate analysis on the graphite properties and the parameters related to the slag reactivity indicated that the kinetics of MnO reduction is mainly dependent on the temperature, and then on the graphite properties. It was also found that at1500 ºC the surface area and the CO2 reactivity are the most important graphite properties for the slag reduction, suggesting that the reactivity of carbon is rate controlling at 1500 ºC. However, the porosity related parameters are the most important graphite properties at 1600 ºC, suggesting that CO gas desorption is rate controlling at high temperatures.

Jan 1, 2007

By H. Maleki, G. Tetreault

This study was initiated by the Bureau of Land Management (BLM) to develop guidelines for determining the maximum economic recovery of resources in coal mines. The work was in response to a requirement in the Mineral Leasing Act of 1920 and Federal regulations. The intent was to address the economic rainability of small, irregular reserves in existing longwall mines. In particular, there was a need to determine if room-and-pillar mining using a continuous miner (CM method) was economically sound, or whether unconventional (short or odd-shaped) longwalls could be used to recover small coal reserves economically. Small reserves, called "widgets" are left in longwall mines on one side of the mains, near outcrops and adverse geological conditions, or near any other location where reserve geometry does not lend itself to mining with a rectangular longwall panel. The work included (1) analysis of the geologic, geo-technical, and economic factors that influence the recovery of small coal reserves, (2) analysis of historic changes in supply, demand, and coal prices, (3) development of typical cost models for room-and-pillar and longwall mines, and (4) development of a practical methodology for determining maximum economic recovery. The methodology included an evaluation of the ratio of coal mined during longwall mining to that mined for development (LDR) as well as costs of maintaining coal quality depending on market conditions. The LDR is a good indicator of mine efficiency and overall coal recovery in modem longwall mines and thus is used to evaluate the

Jan 1, 2001

By Keith Bowers, Frank Mimnagh, Eddie Woods

The CTRL London Tunnels The Channel Tunnel Rail Link (CTRL) London Tunnels comprise 36km of internal diameter bores that were driven by Earth Pressure Balance (EPB) Tunnel Boring Machines (TBMs). The tunnels were constructed between the autumn of 2002 and the spring of 2004. The permanent works also included the 1.1 km long station box at Stratford, five ventilation shafts of depths between 30 and 54 m, 29 cross passages and various large diameter sprayed concrete lined connecting tunnels. The tunnels were driven under densely populated areas of north and east London, as depicted in Figures 1 to 4. Under the parliamentary CTRL Act the project had obligations to make

Jan 1, 2005

This chapter summarizes data on crude nonfuel mineral production for the United States, its island possessions, and the Commonwealth of Puerto Rico. Also included are tables that show the principal nonfuel mineral commodities exported from and imported into the United States and that compare world and U.S. mineral production. The detailed data from which these tables were derived are contained in the individual commodity chapters of Volume I and in the State chapters of Volume II of this edition of the Minerals Yearbook. Although crude mineral production may be measured at any of several stages of extraction and processing, the stage of measurement used in this chapter is what is normally termed "mine output." It usually refers to minerals or ores in the form in which they are first extracted from the ground, but customarily includes the output from auxiliary processing at or near the mines.

Jan 1, 1988

NEW MEMBERS The following list comprises the names of those persons who became members during the period Oct. 10, 1916 to Nov. 10, 1916. ANCHOR, HANS C., Supt., Dome Extension Mines Co., Ltd., South Porcupine, Ont., Canada. BABCOCK, EARLE J., Dean, College Of Min. Engrg., State Univ. Of N. Dak., Grand Forks, N. Dak. BIDDIS0N, P. McDONALD, Construction Engr., The Ohio Fuel Supply Co., 52 W. Gay St., Columbus, 0. BOISE, PAUL T., Asst. Mgr., Stimpson Equipment Co., Felt Bldg., Salt Lake City, Utah. BOURNE, RALPH H., Vice-Pres Whiting Foundry Equipment Co., Harvey, Ill. BROWN, EDWARD OTTO FORSTER, Min. Engr., 706-707 Salisbury House, London, E. C., England.

Jan 12, 1916

By H. Kazemi, G. W. Thomas, M. S. Seth

The double-porosity model of Warren and Root7 for examining pressure drawdown and buildup phenomena in naturally fractured reservoirs has been extended to intetpret interference test results. Both analytical and numerical solutions are presented. The practicality of some of the assumptions in the Warren-Root model was also investigated. The standard procedure for interpreting interference tests in naturally fractured reservoirs beretofore employed an equivalent homogeneous reservoir model. A comparison of our results with the equivalent homogeneous model indicates the latter is inadequate for early time responses. For late time responses, however, the simpler equivalent homogeneous model yields favorable results. Finally, the effects of well spacing and the magnitude of the interporosity flow parameter are briefly cited. INTRODUCTION Interference tests can be used to provide reservoir information not obtainable from conventional pressure drawdown and buildup tests. The technique involves measuring the response in one or more wells arising from a pressure perturbation introduced into another well. It has been. successfully applied to single-layer, homogeneous, unfractured, isotropic and anisotropic formations to arrive at values of well storage capacity and a measure of directional permeability.l The techniques of interference testing usually can be extended to heterogeneous systems, provided the permeability contrast between any existing rock layers is not excessive.9 In such cases, the practical interference effects in an observation well of an interconnecting heterogeneous reservoir can be predicted using an equivalent homogeneous model. The calculated properties are then average values. Russell and Prats2 have demonstrated the utility of this approach for a single-phase, two-layer system. For naturally fractured reservoirs, some different approaches usually are necessary. The major departure from homogeneous or nearly homogeneous reservoir treatment is to characterize the fractured system as an entity having "double-porosity"; namely, we suppose the existence of both primary and secondary porosity, where the former is contained within a systematic array of identical rectangular matrix blocks and the latter is contained within an orthogonal system of continuous, uniform fractures (see Fig. 1). It is sufficient to assume that the permeability of the rock matrix is so small that movement of reservoir fluids to the producing wells is entirely through the fracture network. This assumption has been validated by Barenblatt3 and .employed by others?-7 Warren and Root7 used the double-porosity model to develop an interpretation of pressure drawdown and pressure buildup tests in naturally fractured

Jan 1, 1970

By Thomas, J. Elmer

WHEN the price of crude oil was advanced on July 26, 1928, with some 4,000,000 bbl. daily of potential production shut in under proration regulations, and with as much more new production shortly available from semi-proved undrilled reserves, students of the oil industry were made to realize that a new order of things now prevailed in petroleum economics. A new interpretation of the law of supply and demand had taken the place of the archaic method of influencing current production by changing crude price levels. Proration had caused the change. The long period of over-production just experienced, the prospects of a potential over-supply far into the future, had set up certain forces which brought about some fundamental changes. Their cause, effect and future influence can best be developed by a detailed study of the history of the period since war-time regulation

Jan 1, 1928

By Kirk A. Mcintosh

Augered, cast-in-place (ACIP) piles have been utilized in the United States for a wide range of projects since the 1950&apos;s. Due to the cast-in-place nature of the installation method (and lack of a driving criteria); however, ACIP piles have not been readily accepted by some practicing geotechnical and structural engineers. Since ACIP piles were initially developed, the installation equipment and techniques have been improved and refined and the number of experienced contractors has significantly increased. Over the past 10 to 15 years, the pile type has experienced significant growth in the United States (particularly in Florida) because engineers have become more knowledgeable and comfortable with its use. The Miami area, in particular, has experienced considerable growth in the utilization of ACIP piles primarily due to their usage on the $1 billion Miami Metrorail System project in the early 1980s. The economic advantages over other deep foundation types, coupled with some unique installation advantages, have shown that ACIP piles can be a viable foundation alternative on many projects. Even though ACIP piles have gained respect in the private sector, the pile type has generally not been readily accepted by government transportation agencies. The reluctance to readily accept this foundation type stems primarily from the quality assurance aspect of cast-in-place pile construction. Additionally, there has not been much research activity on this foundation type, technical papers, formal associations (other than the DFI), or a concerted effort to standardize the industry. This paper serves to discuss the state of practice for ACIP pile installation in the state of Florida.

Jan 1, 1997