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By C. G. Clifton

The Oatman District produced approximately 2.2 x 10 6 ounces of gold and 0.8 x 10 ounces of silver between 1897 and 1942. A total of 3.8 x 10 tons of ore averaging 0.58 O/T gold and 0.17 O/T silver was extracted from eight major orebodies and a number of lesser deposits. Oatman lies at the center of a trachyte-latite-rhyolite volcanic complex which contains at least one resurgent caldera. The orebodies are typical epithermal quartz-calcite + adularia lode deposits which are very deficient in sulfur. Ore deposition has occurred within dilatant zones on faults which radiate from a common point within-the complex. Fischer-Watt Mining approached the Oatman District with an integrated exploration program utilizing four basic procedures to define the characteristics of past productive areas the results of which were applied to unexplored portions of the vein system. These procedures, listed in their order of usefulness, in defining known and prospective mineralized zones are: vein contouring, detailed alteration mapping, fluid inclusion temperature determinations, and geochemical sampling.

Jan 1, 1980

By George Joseph Malina

Contractor chose and Owner allowed concrete to be placed using the arch first principle while excavating the 35'-3" O.D. rock tunnel. The contract included excavating and lining 26,000 L.F. of rock tunnel to 33'-I.D. Concrete was placed at a rate of 90LF per working day using a movable bridge to allow batching, mixing and pumping of concrete adjacent to the tunnel form.

Jan 1, 1981

In April 2012, work started on one of the most ambitious construction projects of Austria?s ÖBB-Infrastruktur AG ? the New Semmering Base Tunnel. Scheduled for completion in 2024, the 27.3 km (17 mile) tunnel through the Semmering range will cut the journey time on the south railway connecting Lower Austria and Styria. Before con-struction can begin at the entrance portal and tunnel bores, the work concentrates on the above ground sections with the clearance and excavation of the entrance ramp site. The slope is currently being excavated by the Baubeteiligungsge-sellschaft m.b.H. BBG-GRAZ. The cut face is shored up with shotcrete and permanent self-drilling anchors produced by Minova MAI, an economical bolting solution for softer rock formations. After completing the surface construction work, the twin-bore, single-track tunnel will be cut through the Semmering by conventional and continuous excavation beginning in 2015. Once completed, the New Semmering Base Tunnel will be one of the longest rail tunnels in Austria. It will act as a vital link on the route crossing Europe?s heartland from Northern Germany to Italy, which currently has to climb the steep Semmering pass between Gloggnitz and Mürzzuschlag on a historic mountain railway recognized as one of the UNESCO World Heritage sites. The old route imposes considerable limitations on heavy freight trans-port, and passenger trains have to slow down to a speed of around 50 kph (31 mph). The New Semmering Base Tunnel will bypass this bottleneck and cut 30 minutes off the journey time between Vienna and Graz. It represents a particular advantage for freight traffic, since the new route?s minimal incline of 8.4 percent removes all obstacles for even heavy freight trains.

Jan 1, 2013

By A. B. Van Cleave

It was first pointed out in 1934 by Gaudin (1) that the "oily" oxidation product of the alkyl xanthate ion-dialkyl dixanthogen, might be the "active flotation agent" on sulphide minerals and there have been a number of studies supporting this hypothesis (2,3,4). However, all of these studies have relied largely on electrochemical evidence. Galena, being a semiconductor, may be used as an electrode in aqueous solution and it was shown that ethyl xanthate ion does not adsorb with charge transfer in the absence of oxygen unless the potential of the galena surface is above -100 mv versus the hydrogen electrode (H2 E). At this potential the galena surface is slightly hydrophobic but does not become strongly hydrophobic unless the potential is raised to 210 mv (versus H2 E). It is suggested that, at potentials of 210 mv or above, ethyl xanthate ions are oxidised to diethyl dixanthogen and that chemisorption of oxygen raises the galena surface to this potential. On the other hand, examination of xanthated galena surfaces by chemical or physical methods (5,6,7) has failed to detect dixanthogen and it has been shown that dixanthogen may be reduced to lead xanthate at a lead sulphide surface. (5,8)*. It was suggested by Leja and Poling (5) that, as dixanthogen is a neutral molecule it would not be repelled by the negatively charged galena surface so that the adsorption was envisaged as taking place through homogeneous oxidation of the xanthate ion to dixanthogen, adsorption and reduction of the dixanthogen to a chemisorbed lead xanthate species. In paper I of this series (11) it was shown that the thiosulphate ion, which forms on galena surfaces in slurries at the pH normally used for flotation, will reduce dixanthogen. There is, therefore, the impasse that the electrochemical evidence requires that xanthate ion be oxidised to dixanthogen at the galena surface while the chemical evidence shows that the reverse reaction takes place.

Jan 1, 1973

By John Carr

The tremendous growth in grinding mill size and horsepower during the '70s demanded advancements in gear cutting technology and equipment for the '80s. Computers are used as an aid in the design and selection of the mill drive system; sophisticated computer graphics are used to create manufacturing drawings; and a new generation of gear cutting machines are used to manufacture the gears. These new gear cutters can generate-cut gears over 40' (12.2 m) in diameter at an AGMA quality level exceeding the currenty acceptable standards. The precision of the resulting gear assures maximum tooth contact, which will result in longer gear set life.

Jan 1, 1981

By Michael Karmis

"In December 2011, the U.S. Attorney’s Office for the Southern District of West Virginia, the U.S. Department of Justice, Alpha Natural Resources (ANR) and Alpha Appalachia Holdings entered into a nonprosecution agreement related to the explosion at the Upper Big Branch Mine (UBB) that killed 29 miners. This coal operation was owned by Performance Coal Co., an affiliate of Massey Energy Co., which was acquired by ANR in June 2011, more than a year after the UBB explosion. Pursuant to the agreement, ANR agreed to:• Establish a trust within 120 days.• Pay a total of US$48 million into the trust to be used solely to fund and administer research and development (R&D) projects to improve mine health and safety.• Administer the trust by three highly qualified individuals with academic and/or professional backgrounds in mine health and safety.In April 2012, the Alpha Foundation for the Improvement of Mine Safety and Health was created. The three directors - Michael Karmis, president; David Wegman, vice presidenttreasurer, and Keith Heasley, vice presidentsecretary - approved a plan to expend both the interest and principal of the trust, aiming at an 8-10 year research horizon. The foundation also appointed David Belden, an experienced manager of nonprofits and professional associations, as the first executive director of the foundation. The IRS approved the foundation’s tax-exempt application, as described in Section 501c(3) of the Internal Revenue Code, on Dec. 18, 2012. The board established guiding principles of the foundation, which are as follows:• Mission: to improve mine health and safety through funding R&D projects to qualified academic institutions and other not-for-profit organizations.• Vision: to enable miners in the future to be free of work related injury or disease by the implementation of the results of the projects funded by the foundation and undertaken by the best researchers from any discipline that can contribute. The foundation is now approaching its third year and regularly posts updates, including semi-annual reports, to its website (www.http.alpha-foundation.org/), which serves as the main medium for communication with the broader stakeholder community"

Jan 1, 2014

By C. E. Ekburg

Gold Quarry is a sediment-hosted, epithermal disseminated gold deposit located along the Carlin Trend. Gold, hosted by allochthonous Ordovician siltstones and cherts, is localized at the intersection of structures sympathetic to the major Good Hope and Gold Quarry faults. The magnitude of Gold Quarry was discovered in 1979 by surface exploration and by percussion holes drilled near the Maggie Creek orebody. Four years of development drilling delineated an open pit mineable gold deposit that contains 130 Mt (144 million st) of ore at an average 1.68 g/t (0.049 oz per st) of gold and includes a high-grade core of 46 Mt (51 million st) that average 2.64 g/t (0.077 oz per st) gold. Milling of the higher-grade portion began in 1985.

Jan 1, 1987

By Jan M. Mutmansky

The application of computers and operations research to mine planning problems has changed and progressed significantly over the last several decades with a continuing growth and increased breadth of applications being quite evident. A scan of the volume associated with the 1969 APCOM published two decades ago (Weiss, 1969) indicates that the primary applications in mining were often in the areas of short-term and long-term planning and production scheduling. The applications at that time were oriented toward underground and surface mining, but block and other mine sequencing and scheduling problems for large open pit mines were perhaps the most popular target for the operations research approach. A variety of operations research techniques were used at that time with heuristic models, mathematical programming models and simulation programs all being commonplace. The computers used were usually mainframe models which were of ten shared by accounting, engineering, planning and research groups.

Jan 1, 1989

By Ted H. Eyde

Both private industry and the Interior Department have become alarmed about the enormous amount of Federal land that has been withdrawn from appropriation either under the Mineral Leasing Laws or the Mining Law of 1872. According to a recent article by Gary Benethum and L. Courtland Lee, governmental actions have withdrawn nearly 400 million acres from the operation of the Mining Law of 1872 and over 500 million acres from the Leasing Laws. An addition al 100 million acres for the Mining Law of 1872 and 70 million acres for the Leasing Laws are either encumbered or being managed in such a way as to constitute a defacto withdrawal from mineral development. This means simply that mineral exploration end development under the Mining Law of 1872 is either prevented or discouraged in an area the size of the states of California, Arizona, Washington, Oregon, Nevada, Utah, Idaho, and one half of Colorado combined. Under the Mineral Leasing Laws, exploration and development is either prevented or discouraged in an area equal in size to all the states east the Mississippi River, except Maine.

Jan 1, 1976

By J. A. M. Cano

Pot Grate tests were carried out in the pilot plant at Samarco producing pellets containing SiO2 between 2.0% and 2.2% in a wide range of basicity to be used in blast furnace. These pellets were submitted to tests in Samarco's laboratory and another laboratory in Germany to evaluate the metallurgical properties. The pellets in the binary basicity range (CaO/SiO2) from 0,87 to 0,95 were those that presented the best results in the Pot Grate tests. Based on the results, these pellets are being routinely produced?on industrial-scale confirming the results observed in laboratory tests.?

Jan 1, 1994

By Nai-piu Tong, Huaren Dou, Sui-shun Poon, Leslie H. Swann

This paper mainly presents geotechnical aspects of a vehicular underpass that was built across under one of the busiest highway in Hong Kong. The underpass, in a section comprising an upper arch and invert slab, is approximately 6.2 m high at crown and 15 m wide at the base level with 40 m in length. The construction inevitably requires the underpass to be built using tunneling techniques to keep the overheadroad traffic uninterrupted. The paper will describe the design of temporary support for the tunnel excavation that was provided by an arch formed with horizontal pipes, which were installed using the pipe ramming method. The pipes arch was then supported by steel ribs founded on rock or mass concrete. Permanent lining design consideration was also discussed. Results of numerical modeling of the soil-structure interaction using the 2-D computer code FLAC will be presented. The predictions have been compared to the monitored results during construction, which indicates the prediction is in reasonable agreement with the measurement in the light of ground movement. The construction challenges will also be discussed in the paper.

Jan 1, 2003

By John M. Ackerman

In the spring of 1988, Freeport-McMoRan Resource Partners Ltd. Partnership, IMC Fertilizer Inc. and Homestake Mining Co., as joint venturers, were awarded the sulphur lease for Main Pass Block 299, lease number OCS-G 91372. This was one of 11 leases awarded to the joint venturers. Following the initial discovery wells in December 1988, delineation drilling confirmed proven sulphur reserves of 68 Mt (67 million long tons). Proven, recoverable oil and gas reserves are 6.2 Mm3 (39.4 million bbl) and 1114 Mm3 (7.2 billion cu ft), respectively. Development of the sulphur mine was given approval as a fast-track project in 1989. The oil and gas reserves were acquired from the original hydrocarbon lessee in 1990 and were also given fast-track status. Fast-track for these projects meant design and engineering would not be complete before construction began. Joint venture The Main Pass Joint Venture is one of 13 joint ventures formed between Freeport and three other companies - IMC Fertilizer, Inc., Felmont Oil Corp., a wholly owned subsidiary of Homestake Mining Co., and Texasgulf Minerals and Metals Co. Felmont has since changed its name to Homestake Sulphur Co. Texasgulf assigned its interests to its parent company. Texasgulf did not participate in the Main Pass 299 joint venture. Joint venture negotiations, anticipating a lease sale in mid-1988, began in December of 1987. This joint venture, the first of its kind, was created to acquire offshore leases, explore, develop and mine sulphur. The Interior Department's Minerals Management Service (MMS) announced a lease sale date of Feb. 24, 1988 on the first business day of 1988. This greatly accelerated the joint venture negotiations. Of the 13 leases the joint ventures bid on, 11 were awarded. Freeport holds its interest in all the leases through its ownership interest in Freeport-McMoRan Resource Partners, Ltd. Partnership. Resource Partners is the operator on all of the leases.

Jan 1, 1992

By Milton E. Wadsworth, M. Ken Han

The kinetics of leaching of galena in hydrochloric acid solutions with sulfur dioxide gas have been investigated experimentally. The leaching method is then applied to complex sulfide concentrates to evaluate its selective leaching capability and to develop a new hydrometallurgical lead extraction process based upon the method. The leaching reaction follows a linear rate with an activation energy of 61.9,KJ/mole. The rate Is of first order with respect to the product [H+] [Cl-] . Excel lent selective leaching capability f s demonstrated and an attractive hydrometallurgical process flow sheet is proposed.

Jan 1, 1989

By J. C. Norman

The boron review arrived too late to appear in the June issue. The United States was the world's second largest producer and the largest consumer of boron compounds during 1991. According to the US Bureau of Mines, boron mineral concentrate and chemical production in the US totaled about 1.1 Mt (1.2 million st), yielding about 608 kt (670,000 st) of BO, in 1991. Total estimated value was $440 million. That level of production was equal to 1990 revised production figures. Value was greater by $37 million, however, reflecting a strengthening of boron product prices. The US continued to supply essentially all its own boron while maintaining a strong position as a source to foreign markets of sodium borate products and boric acid. Domestic employment in the mining and beneficiation of boron products in 1991 remained at 1100 people, about the same level as in 1989. The Bureau of Mines estimated total world production of boron in 1991 - mineral concentrate and chemical - at about 2.9 Mt (3.2 million st). That corresponds to about 1.2 Mt (1.3 million st) of BO ,. World production in 1991 was about equal to revised 1990 levels. US production Mines and processing operations in southern California were the only domestic sources of boron mineral concentrates and chemicals in 1991. US producers, in order of quantity of production, were US Borax and Chemical Corp., North American Chemical Co., and American Borate Co.

Jan 1, 1992

By C. Alan Tapp

Introduction Mine sampling determines the practicality of any mining operation. Improper sampling can result in an incorrect appraisal of present production and future potential. Therefore, the mine department in charge of ore-reserve calculations and mine sampling should be overseen by competent and experienced professionals with technical backgrounds qualifying them to produce accurate results. Sampling is a process by which portions of an ore body are collected and analyzed to estimate the average mineral content of the entire ore body. It is incorrect to assume that a large number of samples eliminates any errors in the sampling method. To obtain unbiased samples, proper sample location with respect to rock type and mineralization is just as important. The sampling procedure must yield correct results for the type of mineral deposit, and careful consideration should be given to whether or not the sampling technique has been developed to an extent sufficient to eliminate as much human error and bias as possible. Only after the ore has been mined and milled is the sampling accuracy known. Sampling also provides information about the bulk composition of the ore for mineralogical and metallurgical tests that determine the economic ore-waste boundaries and the geologic trends for exploration. Actual mining plans can be developed from this information to maximize profits. Accurate sampling is critical, and thus must be approached in a scientific manner. Sampling Techniques Sampling practices and techniques are as varied as the mines in which they are used. The method(s) chosen must be tailored to suit the company and mining needs. For instance, tabular uranium deposits, vein gold deposits, and porphyry copper deposits pose special problems in conducting unbiased sampling. The mine geologist or engineer in charge must develop a sampling method, test it in a sample area, and then critically evaluate the results. If the results from the test area are accurate within the economic limits established by the company, they then may be adopted for general use in the mine. Four routine sampling methods are suitable for specific sampling objectives in the daily mine routine: (1) channel sampling, (2) chip sampling, (3) grab sampling, and (4) bulk sampling. The final sampling results depend upon how the four methods are combined to accurately determine the grade of the ore body. When used in conjunction with each other during different stages of mine development, the channel, chip, grab, and bulk sampling methods provide an in-house check or a comparison by which mining methods and sampling procedures can be evaluated. However, the most valid check is based upon the daily mill production. Channel Sampling Channel samples consist of cuttings collected from a groove cut into the rock about 102 mm (4 in.) wide and 19 mm (0.75 in.) deep. Various tools ranging from a 1.8-kg (4-lb) hammer and moil to a pneumatic chisel can be used to cut the sample. Accessibility and rock hardness determine the applicable sampling tools. Before attempting to take a sample, the rock surface must be cleaned thoroughly; the method of cleaning depends upon the amount of mine dust accumulated on the surface or the degree of alteration of the rock surface. Typical cleaning methods 'employ a wire brush, water, or chipping a fresh surface. Next, the sample outline is marked on the prepared surface, taking care to choose appropriate sample loca- tions. After determining the proper sample outline and length, the sample can be chiseled out, catching the rock fragments on a canvas tarpaulin on the floor, in a powder box, in a canvas bag to avoid contamination, or by some other suitable means to capture all of the sample. Vertical veins present a special problem because the drift's back usually is arched, not square. For example, Fig. 1 shows that if sample intervals are measured from A' to D', the length of the sample interval is greater than the true vein width, resulting in an incorrect calculation of the ore reserves. The correct method would collect three samples at A'-B', B'-C', and C'-D', using either actual measurements in the mine represented by A-B, B-C, and C-D or trigonometric calculations to determine the true ore thickness. Then, each sample can be weighted by grade and true thickness for the vein. Channel lengths usually are a maximum of 1.5 m (5 ft), and it is good practice to divide longer samples into smaller intervals according to structures, changes in rock types, or differences in rock hardnesses. The influence of those features on the mineralization then can be determined. Chip Sampling Chip sampling is a variation of channel sampling used when the rock is too hard to channel sample economically or when little variation in the mineral content indicates that this sampling method will yield results similar to those of channel sampling. Rather than cutting a channel in the rock, small chips are flaked off at regular intervals over the entire face or area being the mine. sampled. Care must be taken to assure that the sample is representative of variations in the rock hardness and type. hi^ method is fast and useful in preliminary evaluations, but it should not be used for quantitative ore-reserve calculations. Grab Sampling Grab sampling is a fast method for double checking either channel or chip-sampling procedures, and, in some instances, mine production can be estimated from carefully taken grab samples. Grab sampling takes equal amounts of material at selected intervals over a mine dump, a muck pile, or from an ore car to estimate its Channel Sampling mineral content. Generally, this method is not considered reliable. Many independent variables can affect this type of sampling process. Thus, if the ore occurs in the softer fraction and a proportional amount of the result-

Jan 1, 1982

By William P. Lorenz

Overlying the sulfide mineralization at Anamax Mining Company's Twin Buttes Mine is an oxidized zone up to one hundred meters in thickness. The principal copper minerals in this zone are chryso-colla, tenorite, cuprite, native copper and copper-manganese-iron wad. This ox¬idized zone also contains minor amounts of uranium ranging in concentration from 0.002 to 0.010 percent. Since pit development through 1980, some 38 million tonnes of oxide ore with copper contents greater than 0.6 percent have been brought to the surface. Copper in the oxide ore is extracted at Twin Buttes in, an agitated sulfuric acid leach plant followed by solvent extraction and electrowinning producing 90 tonnes per day of copper cathode. During leaching of the oxide ores small amounts of uranium are solubilized along with the copper values. This is not limited to Twin Buttes as most acidic copper bearing leach solutions throughout the southwestern United States contain small amounts of uranium.1

Jan 1, 1982

By Peter S. Schneidkraut

This paper will discuss the Final Tunnel Linings which were placed in 6700m of a 2.32m inside diameter precast concrete lined interceptor sewer tunnel in Staten Island, New York. Two methods were employed to install the final tunnel linings. One method involved forming and placing a polypropylene fiber reinforced concrete cunnette invert, followed by an arch pour. The second method involved the jacking of reinforced concrete pipe into the tunnel, followed by a low density cellular concrete backfill grout. These two methods will be described and compared.

Jan 1, 1993

By M. Ge

An in-seam seismic (ISS) - based void detection technique was developed and tested for three general mine conditions: anthracite, bituminous and trona. The detection range tested varied from 80 to 100 m for trona mines and from 33 to 66 m for bituminous mines. High quality and broad band signals were obtained from these tests and were used to delineate the voids. The paper provides a brief discussion on the technical features of this void detection technique, the testing conditions and results, and a general assessment of the technique.

Jan 1, 2010

By J. B. Hiskey

The principle oxide minerals of molybdenum are wulfenite (PbMoO4), ferrimolybdite (Fe2(MOO 4)3.nH2O), powellite (CaMoO4), and ilsemannite (Mo304). Wulfenite is found in Arizona, New Mexico, Nevada, Utah, California, and Montana. It is also found in the states of Sonora and Chihuahua, Mexico. Prior to 1915 wulfenite ores were the primary source of molybdenum. The solubility of wulfenite in hot sodium sulfide was first noted by Bonardi(1) during attempts to sulfidize wulfenite material prior to flotation. He identified lead sulfide and soluble sodium molybdate as reaction products. Bacon (2) sulfidized wulfenite in preparation for flotation and by X-ray analysis found the reaction product to be lead sulfide. Holmes(3) made an extensive investigation of the extraction of molybdenum from wulfenite concentrates by leaching. Nearly 100% molybdenum extraction was possible from -100 mesh samples leached for 15 min with 10% sodium sulfide solution at room temperature. Molybdenum extraction from -100 mesh samples after leaching 30 min at a temperature of 45°C using 2, 4, and 6% sodium sulfide was about 32, 79, and 98% respectively. The extraction showed little sensitivity to time, temperature, or particle size using 10" sodium sulfide solution.

Jan 1, 1976

By G. A. Kordosky

The control of pH in solvent extraction circuits is an old technique (1,2) but one which has a large potential for future use. The equilibrium position of any reaction which has hydrogen or hydroxide ions, either as products or as reactants, can be controlled by pH adjustment. Several examples of reaction types which are important in solvent extraction systems and which also show a pH dependence are shown in Figure 1. The examples were chosen to show the wide variety of reactions which fit the above criteria, but it is not meant to be a complete listing of all the possible reaction types, Some of the reactions are presented in a simplified form. It is the intent of this paper to discuss pH controlled solvent extraction reactions for some relatively simple systems through more complex ones.

Jan 1, 1979