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By Mustafa Yalçin, Ali Ihsan Arol

Coconut shells are the most widely used raw material for the production of activated carbon used in the gold production by cynanide leaching. There have been efforts to find alternatives to coconut shells. Shells and stones of certain fruits, have been tested. Although promising results to some extent were obtained, coconut shells remain the main source of activated carbon. Türkiye has become a country of interest in terms of gold deposits of epithermal origin. Four deposits have already been discovered and, mining and milling operations are expected to start in the near future. Explorations are underway in many other areas of high expectations. Türkiye is also rich in fruits which can be a valuable source of raw material for activated carbon production. In this study, hazelnut shells, peach and apricot stones, abundantly available locally, have been tested to determine whether they are suitable for the gold metalurgy. Parameters of carbonization and activation have been optimized. Gold loading capacity and adsorption kinetics have been studied.

Jan 1, 1995

By Robert M. Becker

The evaluation of in situ rock stresses from measurements of the change in diameter of a borehole that is stress-relieved by overcoring has become a common practice. Generally the stress evaluation has been based on isotropic relations whereas rock in varying degrees is anisotropic. A plane elasticity solution for a circular hole along one axis of an orthotropic medium has been adapted to evaluation of in situ stress. The necessary elastic parameters for this evaluation may conveniently be obtained from static tests on the overcore in conjunction with a consistent orthotropic thick-wall cylinder solution. The method and equations for the laboratory and field evaluations are summarized and illustrated.

Jan 1, 1968

By William E. Robinson

Our earthly treasures are being quickly depleted. We have experienced what can happen in an energy crisis. You have read and heard all kinds of stories as to what caused this crisis. On the surface it would seem that all of a sudden a situation becomes a crisis whether it be fuel, potatoes, beef or whatever. Well, of course, they don't just happen. There is always a little fore-warning here, an indicator there. Someone recognizes a sign of potential trouble but is ridiculed when he forecasts it. We are running out of sand: Producers of aggregates who can say today ... "That couldn't happen to me", can well be awakened tomorrow to the cold fact of reality. It could come from any number of directions. Depletion is mostly foreseeable but zoning isn't. Legislation can also be sudden death to availibility. With the ever growing population moving into the rural countryside, available deposits are being sold either to developers or being zoned for restricted use. The fact that a gravel pit or quarry is located on a particular plot has not fazed some of the local planning boards when they decided to place the adjoining property in a residential Zone A. Proponents of zoning preach that such use is necessary to insure that the land will be put to its best use. Planning boards establish the best places for schools, homes, shopping areas, factories, etc., so that the individuals or groups are in harmony with each other. This is usually done to date without thought or consideration to the geological importance or potential of the area. Today over half of the United States is living under some form of land use restriction. Little consideration has been given to what lies under the ground to be zoned. Fortunately, the states are slowly getting around to geological surveying. I feel that it is about time that state and federal authorities institute governmental restrictions to prohibit or control local zoning ordinances which would deplete or deny an area of its natural resources. While I could continue for the balance of my time just on this facet of our industry's problems, my point is: How sure are you of your next load of sand? I could be well laughed at by some of you for saying that there is an alarmingly rapid disappearance of "nearby" sand and gravel reserves in many areas of the country. A questionable statement, except to those producers where depletion has already taken place.

Jan 1, 1974

By Mohamed A. Younis, Robert J. F. Goodfellow

This paper investigates the design approaches taken and the philosophy employed during the construction of the Metropolitan Airport Commission (MAC) storm tunnels, part of the Phase 4 Segment of the MAC Trunk Storm Sewer Project at Minneapolis St.-Paul International Airport, located in Minneapolis, Minnesota. URS Corporation was retained to provide a design and Construction Management (CM)services for the MAC Trunk Storm Sewer Project. A case history of the design and construction challenges of the project is presented. The MAC storm tunnels consisted of the construction of twin 10-foot inside diameter (I.D.) tunnels within 7 feet of an existing 72-inch I.D. storm pipe at the base of a 70-foot high highway embankment. The analysis required during the design stage of the project is discussed. This analysis and our design approach provided a defensible framework and justification to make design decisions on relevant issues including: allowable spacing of new and existing structures; preferred order of construction; expected ground deformation behavior; response of lining types to adjacent construction; and effects of proposed changes to design at the submittal stage and during construction.

Jan 1, 2003

By H. S. Duzgun, N. Demirel

Estimating productivity of a walking dragline is of paramount concern to mining engineers and mine planners. Risk based evaluation of the dragline productivity is a valuable tool to estimate the dragline’s long-term availability, to develop preventive maintenance plans and to make future projections about the dragline’s performance. This paper aims to provide mining professionals with an overview of risk assessment methodology for productivity of two walking draglines, Page 736 and Marion 7820, which have been operating in the Tunçbilek openpit coal mine of Turkish Coal Enterprises (TKI) in Turkey. The study encompasses three main stages: (i) acquiring of monthly maintenance records, operating hours, mechanical and electrical failure hours between 1998 and 2009; (ii) reliability modeling using mean time between failure data and (iii) determining hazard rate and consequences to compute risk associated with dragline productivity. The results showed that that Page 736 (15.29 m3) seemed to be more reliable and less likely to fail when compared with Marion 7820 (30.58 m3). The operating hours without failure range from 41 to 51 hours with 50% reliability.

Jan 1, 2011

By John A. Lombardi

The HW Process Technologies Engineered Membrane Separation (EMS"') technology is a patented system for the removal of multivalent base metal cyanide complexes from cyanide process streams, and EMSni permeate, concentrate and recovery terminology is explained. Specifically, use of the EMS™ system for the removal of Cu(CN)i- and Cu(CN)43- cop­per from cyanide process streams is discussed. The historical "Copper-Gold" processing paradigm of copper related cyanide consumption and complexation and methods to recover copper and copper complexed cyanide from Cu-Au process solutions are summarized. An advanced stage R&D sequential Cu-Au leaching circuit is proposed wherein two PLS streams are generated, i.e., a high copper tenor "first flush" Cu-PLS and low Cu tenor "second flush" Au-PLS. Copper and cyanide recovery from the EMS"' concentrate generated by Cu-PLS EMSTI,f processing by well known acidification processes and lesser developed, but techni­cally feasible, electrowinning processes are projected to be lower cost than similar dilute solution treatments. Gold is described as Merrill-Crowe plant recoverable from the EMS™ permeate stream coming from the Cu-PLS EMS"' process. Gold is also recovered from the EMSTI,f permeate generated by the processing of an Au-PLS bleedstream. The economics of the proposed Cu-Au-EMS"' circuits are estimated as $2/ gpd capital cost for large systems and $1- $3/ l 000 gallons treated operating cost plus royalty.

Jan 1, 1998

By Keith G. Wallace, Gary K. Rogers

As a supplement to an analysis involving methodologies for the estimation of airflow resistance in shafts used for both ventilation and hoisting, a detailed shaft characterization survey was distributed worldwide. The survey provided detailed information which enabled verification of recommended velocities and established limitations on fill factors and relative velocities. This paper evaluates the information obtained for 37 shafts and presents a statistical evaluation of the results. Apart from airflow rates, conveyance rates, and physical characteristics, qualitative information regarding means of conveyance stability and velocity control techniques at unloading and loading points are also presented. Calculations of fill coefficient, free area velocity, and most importantly, relative velocity between the airflow and hoist, are conducted. These results are presented by frequency diagrams which illustrate the trends, as well as provide limitations for these parameters. The data illustrates that, commonly, the fill coefficient for two or more conveyances, does not exceed 30 %. A limit of 50% is suggested for a single conveyance shaft. A recommended free area velocity of 10 m/s (1,970 ft/min) for combined ventilation and hoisting shafts, is sup- ported by these results. Relative velocities of 30 m/s (5,905 ft/min) are most frequent and 50 m/s (9,840 ft/min) being a practical maximum.

Jan 1, 1987

By T. Tamagawa, I. Iwasaki, N. X. Fu, M. Kobayashi

A three-stage fluidizing-bed process consisting of chlorination, selective oxidation and sulfur chloride conversion was tested for processing chalcopyrite concentrate. It was found that the use of excess oxygen was essential for the stable operation of the oxidation reactor. The excess-oxygen gas inevitably causes the oxidation of the sulfide concentrate in the chlorination and sulfur chloride conversion reactors. A new flowsheet is proposed to separate the chlorination and selective oxidation steps with separate flow paths of the fluidizing gases, thereby, preventing the passage of excess-oxygen gas in the chlorination and sulfur chloride conversion reactors. The feasibility of the proposed flowsheet was demonstrated in a laboratoryscale fiuidizing bed setup.

Jan 1, 2002

By Raymond E. Krauss

The McLaughlin Mine is based on a world class epithermal gold deposit located in the coastal thrust fault of northern California, about 1 12 air km (70 air miles) north of San Francisco. Owned and operated by Homestake Mining Co., the McLaughlin deposit contains about 18 Mt (20 million st) of gold ore at an average grade of 5.2 g/t (0.152 oz per st), or about 93 t (3 million oz). The area was identified as a gold target by Homestake in early 1978. Drilling confirmed it to be a commercial deposit by 1980. The mine was then planned, engineered, built and brought into production by March of 1985. The deposit was historically a part of the Knoxville District. It was mined for cinnabar, which was used to produce mercury for use in recovering gold and silver in the Mother Lode and Comstock districts. At that time, the mine was called the Manhatten and later the One Shot Mine. It was worked for more than 100 years, producing about 76,000 flasks of mercury without any awareness of the presence of economic concentrations of gold. By 1978, the site was largely disturbed and entirely unreclaimed.

Jan 1, 1990

By Ronald H. Mullennex

The growing need for development of thinner, more erratic, or less easily- mined coals in the Appalachian region requires more detailed analysis of conditions and factors controlling or influencing deposition of these seams. The value of depositional modelling in evaluation of such coals has been demonstrated in many recent studies and publications. Such modelling may be applied to allow prediction of factors varying from regional coal occurrence trends to very local areas of seam discontinuities, but requires thorough utilization of all available types of data. Mapping of general depositional energies, as derived from basic geophysical and driller's logs, can be applied to specific prediction of coal occurrence, and projection of particular facies as representative of unique depositional features or conditions often proves more applicable to coal character delineation than does mapping of the coal itself. Depositional modelling and trend projection may also serve as a guideline in reserve classification and confidence-levels in reserve estimations.

Jan 1, 1981

By L. A. Arrington-Webb

Forty-four states produced clay products during 1994 for a total value of $1.6 billion. This was a 3% increase in total tonnage and a 7% increase in value from 1993. Kaolin Domestic production of kaolin during 1994 was estimated to be 9.3 Mt (10.2 million st), according to the US Bureau of Mines (USBM). Georgia remained the leading producer with 7.5 Mt (8.2 million st), followed by South Carolina with 535 kt (589,000 st). Kaolin used as a paper coating or filler pigment accounted for 51% of domestic consumption. Other uses included grogs (14%), fiberglass (5%) and plastics (4%). A reclassification by an Alabama producer of fire clay to kaolin accounts for the introduction of kaolin used in grogs. This also accounts for the apparent decrease in the use of kaolin in paper from 60% in 1993. However, the actual amount of kaolin used in paper was the same.

Jan 1, 1995

By R. L. Grayson, G. Mishra

Introduction Many old underground mines have been developed extensively into reserves requiring large numbers of workers to maintain and rehabilitate lengthy track haulages and/or belt conveyor systems. Often, large numbers of fans are required to maintain minimal airflows in areas where poor conditions and huge leakages prevail. Problems that beset one such coal mine and projects undertaken to restore it to potential profitability are presented. Brief history The Vesta No. 5 mine was opened in 1908. Drift development began near the Monongahela River, which was the primary avenue for shipping metallurgical coal to coke ovens in Pittsburgh. Over the ensuing 75 years, the main haulage entries were developed a distance of 16.1 km (10 miles) to the present mining area. Track haulage was used to transport coal from working sections to the river loading facility. As haulage distance and areas of high water influx increased, management decided, in 1973, to construct an underground conveyor belt system. The project spanned 36 months and culminated in a system of 22 flights, ranging from 205.7 to 1767.8 m (675 to 5800 ft) long. Six intake and eight return entries were developed as the mains were advanced. These entries provided adequate ventilating capacity over the years, but as extensive gob areas progressed and roof conditions deteriorated, the entries became inaccessible and more resistant to airflow. By 1981, five fans were being used to circulate 943.9 m3/s (555.5 cfm) of air through the mine. An average of 6440 t (7100 st) were produced from 20.8 continuous miner unit shifts and 2.7 longwall unit shifts each day in 1981. The ratio of support to production personnel was 1.94. To maintain the outby 16.1 km (10 miles) of haulage, 110 personnel were used. The average cost per ton was $43.54 ($39.58 per st), resulting in excessive bottom-line losses. The mine possessed a rather promising reserve, mostly in lease, of good quality, medium-sulfur metallurgical coal, but it also had a number of formidable operating problems. Operating problems Contributing factors toward relatively low productivity and high costs were the conditions of the track haulage, conveyor, and ventilation systems. Productivity was affected greatly by downtime associated with the conveyor system, which lacked adequate access for making splices or other repairs. Many areas within the conveyor belt entry itself required more

Jan 1, 1988

By William Hodder, Ehsan Alavi, Muhib Hussain

Disc Cutter Wear is influenced by several geological and technical factors and excessive wear can have a major impact on the excavation efficiency of Tunnel Boring Machines (TBM). Disc cutter replacement events cause a disruption to the construction schedule and costs, and should be minimized throughout the project to the extent possible. A well-executed cutterhead inspection and maintenance plan can help mitigate abrupt cutterhead interventions and reduce its effect on project schedule and cost. This paper examines cutterhead inspection and disc cutter replacement events as well as subsequent wear data recorded in the first 7km of the 10.3 km long, 6.3 m diameter Coxwell Sanitary Bypass Tunnel (CBT) project in Toronto, Ontario. The CBT alignment is mainly through Georgian Bay Formation shale.

Dec 1, 2022

By C. C. White

Although many notable scientific investigations relating to roof control have been made, roof control still must be considered one of the more baffling problems confronting the miner. Each year contributions are made to our understanding and techniques in dealing with various single phases of the overall problem, however, an equation considering all the variables involved in roof control, if formulated, would indeed be hopelessly complex. Among the factors to be considered is first, gravity which is always acting but which is sometimes less of a problem than lateral forces. There are lateral forces due to expansion, resulting from the weight of overlying rock; to these must be added lateral stresses of orogenic or tectonic orgin, which may be enormous. Stresses due to plastic flow of beds, water pressure, gas pressure, expansion due to absorption of water, faults, joints, fractures, pot heads, and the like may complicate the solution. Therefore, we must base decisions on roof control, and roof bolting in particular, largely on experience, and far too often on few "knowns" and many "unknowns", The development of "in situ" roof trusses may prove of benefit because, they unlike roof bolting, promise positive calculable roof support. These trusses require installation of steel tensioned rods in the roof, which rods are arranged to produce a stress pattern similar to a bridge truss, the roof rock acting to transmit the compression forces. The simplest form of truss (see figure 1) consists merely of two steel rods anchored at the back of holes drilled at an angle of approximately 45° over the pillars, collared near the the middle of the room, the lower ends of the rods being connected together by tierods and turnbuckles. Used in this way, a 3/4" diameter rod can offer greater support than a 10" x 5-3/4" wide flange steel beam. By tightening the turnbuckle, uplist on the roof can be produced,, the downward reaction being transmitted to the pillars by the rods. This simplest form of truss has been used in rooms up to 24' in width. Trusses of four panels, that is, consisting of a truss within a truss, as shown in figure 2, have been used successfully in rooms 30' wide. (figs 2 & 3) It appears a 6 panel truss could be used in a 40, wide room.

Jan 1, 1968

By V. Shchukin

According to the scientific views formed by the middle of nineteen seventies there should be no possibility of commercial diamondiferous kimberlites in the north of the west European platform. However a later analysis of the geological data gave rise to the concept that diamond bearing kimberlites would be present in the north but on the mineralogical level they would differ from kimberlites of South Africa and Yakutia. Further investigations resulted in the confirmation of these conclusions and with discovery at the beginning of 1980 of diamond bearing kimberlite pipes in the Arkhangelsk region.

Jan 1, 1995

By C. E. Capes

The continuous balling? operation whereby a moist particulate mass is tumbled in a horizontal revolving drum with recirculation of the undersize product can be extremely unstable. Product and recycle rates are subject to wide fluctuations. Although the problem seems to be well-recognized, there is little published information or quantitative data readily available, especially in relation to industrial-scale circuits. Probably the best available published results are in the Russian literature, an illustration of which is given in Figure 1. These data, taken from a study') of some of the factors which influence the stabilization of the pelletizing process, illustrate the wide variations in circulating load and circuit productivity which may be encountered over a period of operation. The problems of balling circuit stability may be traced to random seed or nuclei generation and uncontrolled agglomerate growth. The situation is analogous to that in crystallization processes where (4 considerable attention is given to nucleation control. Traditionally attempts have been made to optimize system and operating variables to stabilize the balling process. A supplemental approach which is taken here is to build on the considerable

Jan 1, 1975

By Ronald A. Crowson

Detailed stratigraphic studies of the overburden at North Carolina Phosphate Corporation new South Creek Mine have delineated several aquifers and acquicludes within the 30-meter-thick overburden section of late Pleistocene sands and clayey sands. A major aquifer occurs in the 10-meter-thick sequence of shelly sands of the early Pleistocene Croatan Formation. The water-charged Croatan sands thicken into a paleodrainage surface on top of the Pliocene Yorktown Formation, a major aquiclude. A three-phase dewatering program is projected: 1) improve surface drainage around mine perimeter to reduce both flowage into the pit and rainfall recharge; 2) use a wellpoint system to dewater the upper 8 meters; and 3) use recharge wells along the axis of the paleo- drainage to dewater the overburden below 8 meters.

Jan 1, 1983

By C. P. Boddy

One of the most difficult tasks a project manager will have in pre-mine planning is dealing with the mine site's hydrologic regime. Numerous federal statutes passed by Congress in the last decade have made the coal mining industry more responsive to the environmental impact during all phases of the mining process. Permitting these mines has dictated a cradle to grave approach in dealing with water related issues. This paper will attempt to explore the application of these technology- based laws and their direct application to the unique environment found in Alaska's interior regions.

Jan 1, 1985

By Sam M. Pickering

Most high, purity silica is produced from crystalline quartz-generally from sand. However, there is a small area of southern Illinois where a porous, friable white chert rock is found which is very different in physical form from quartz sand. This microcrystalline material, commonly referred to as tripoli, is more easily ground to micron sizes than sand. Although of similar Moh's hardness, microcrystalline tripoli is less abrasive than either ground quartz sand or many synthetic abrasives. Location The southwestern corner of Illinois is underlain by extensive deposits of very porous chert; in some places the material is quite white. Two companies - Illinois Minerals Co. and Tammsco, Inc. - mine and process this white material. The Illinois Minerals plant is located at Elco, and the Tammsco plant is in Tamms, Illinois. Both companies mine from various locations within a ten mile truck haul of their plants. Production from this district has been continuous since at least 1915. Malvern Minerals Company mines and processes a generally similar microcrystalline, friable novaculite near Hot Springs, Arkansas.

Jan 1, 1985

By Hassan El-Shall, Rosana M. Macedo Borges, Ponisseril Somasundaran, Regis Stana, José Renato B. Lima, Patrick Zhang

The phosphate fertilizer industry is a large activity in Brazil because the soil has a phosphorous deficiency. The phosphoric acid that is produced is extensively used in the production of fertilizer. It is produced by reacting phosphate carbonaceous rock with sulfuric acid, generating phosphogypsum as a by-product. In 1991, there were about 29 million tons of phosphogypsum stored in Brazil. This has increased to an estimated 280 million tons in 2001. While the phosphogypsum is used in the cement industry and also in agriculture, the quantity used is much less than the production rate, and the stockpiles are still increasing. The radioactivity of this waste may not allow its continued use as a construction material and some other uses. However, Brazilian phosphogypsum contains a smaller quantity of radioactive materials than is reported for phosphate rocks from other countries. One important reason is the geological origin of the Brazilian apatite. All the large deposits being currently mined are igneous, not sedimentary, as is the majority of the phosphate rock produced around the world. An extensive study is being conducted to characterize the phosphogypsum generated in two production facilities in Sao Paulo state to develop safe uses for this waste and determine the environmental impact caused by the present method of phosphogypsum disposal.

Jan 1, 2002