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By Sheridan J. Rodgers

Improved methods of dust control in the metal and nonmetal mining industries were studied. Preliminary dust surveys were made at selected mines and three mines were chosen for additional studies. Dust control effectiveness was evaluated using full shift gravimetric sampling and GCA Dust Monitor readings. Analyses for free silica content and particle size distribution were conducted. A belt washing system which was used to control dust at a transfer point was evaluated. The average reduction of respirable dust was 48% and the average reduction of total dust was 78%. The belt washing system not only maintained the work place within compliance but reduced maintenance problems along the beltway by 90%. Exhaust ventilation at a crusher was evaluated for control effectiveness. Ventilation along with operation of the crusher control room under slight positive pressure, maintained the work place within compliance. An exhaust ventilation system was designed for use at an underground rotary dump. Although the system was not installed or evaluated, details on the design are given. High expansion foam was used at an ore chute in an attempt to control dust at the draw point and loading point. Results indicated that foam did not effectively control dust.

Jan 1, 1978

By M. Martins

This work presents and discusses the influence of the surface tension (gLV) of methanol/water mixtures on the flotation response of apatite versus gangue minerals conditioned with flotation reagents (75 g/t cornstarch and 100 g/t Berol 867) at pH 10.6. Berol 867 is a collector composed of sodium alkyl sarcosinate plus nonionic surfactant. The highest Schulz efficiency of separation (recovery of apatite minus recovery of gangue) was achieved at ?51.0 mN/m. The critical surface tension of wettability (gC) of apatite was found to occur at 34.7 mN/m when determined by means of gamma flotation experiments, and it was 33.9 mN/m when determined by Zisman?s approach.

Jan 1, 2009

By J. L. Thompson

The U.S. Bureau of Mines conducted a water-jet-studies program using a single-bit, in-seam test unit to determine effects of a moderately high-pressure (up to 10,000 psi) water-jet-assisted cutting system on rock weakening. The in-seam test unit was used to obtain cutting force data in tangential, normal, and side force directions. Conical continuous miner and radial longwall miner bits were used to penetrate test samples of coalcrete, Berea sandstone, and Indiana limestone with unconfined compressive strengths of 4,600, 8,000 and 10,000 psi, respectively. Depth of cut in the coalcrete tests was 1 in, with 2-in cut spacing (2:1 ratio). Because of cutting equipment and instrumentation limitations, the Berea sandstone and Indiana lime-stone were cut using a 0.5-in depth of cut and 2-in spacing (4;1 ratio). Bit velocity was maintained at 25 ft/min for both bits. Each specimen and bit type was tested using 0.3-, 0.6-, 0.8-, and 1.0-mm-diam nozzles and water-jet pressures of 2,500, 5,000, 7,500, and 10,000 psig. Water-jet-assisted cutting decreased average resultant conical and radiallongwall bit cutting forces 6.4 and 8.4 pct in coalcrete, 5.5 and 1.4 pct in Berea sandstone, and 2.0 and 5.5 pct in Indiana limestone. Slight reductions of power requirements resulting from water-jet assist were ascertained during these experiments.

Jan 1, 1989

By J. C. Engel

Recent innovations in mine safety include the use of mercury vapor lamps for mine vehicle illumination. Such lamps, however, extinguish whenever the line voltage at the machine momentarily sags or is interrupted. The lamps must then cool for several minutes before they will restart. By supplying reduced high frequency power to the lamps from an auxiliary source, it is possible to maintain ionization in the arc tubes preventing the lamps from extinguishing. Essentially an auxiliary high frequency supply, the keep alive system provides additional power to the lamps automatically whenever the lamps are in danger of dropping out. The system can also provide the operator with the ability to dim the lamps at will for periods of up to three minutes by simply interrupting the 60 Hz power to the conventional ballasts. Each unit, housed in a steel explosion proof enclosure with a volume of approximately 0.6 ft3, is capable of servicing up to six 175 watt H-39 mercury lamps and two 100 watt H-75 reflector flood lamps. A total of 16 units were produced for the USBM under this contract and its extension.

Jan 1, 1979

By Jay L. Hodkinson

Replacement of an aging twin span river crossing in Vermont required a temporary bridge to accommodate traffic during construction. Soils beneath the temporary approach embankment consisted of very soft organic clayey silt underlain by interbedded, loose alluvial fine sand and silt/clayey silt. Reinforcement was required for the southern temporary approach embankment to limit settlement and to increase global stability factors of safety. A ground improvement design was developed using Rammed Aggregate Pier® reinforcement and was included in the contract documents as an FHWA Category II Experimental Feature. Instrumentation intended to document the performance of the supported embankment was installed. Piers were then constructed and monitoring commenced as embankment and bridge construction occurred. Weekly instrumentation data reports indicated continuing excess pore water pressure, settlement, and lateral deformation of the subgrade soils as the embankment and temporary bridge abutment was constructed. In response to the unanticipated monitoring results, further investigation indicated that significant deviations from the conditions and basis upon which the ground support design was developed were made during construction. This paper discusses these deviations and their specific impacts to embankment support performance, how these deviations occurred, the role that the ground support system played in maintaining global stability, measures taken to limit further detrimental impacts to the embankment, and provides recommendations for contract document preparation and construction oversight to prevent similar situations from occurring on future projects.

Jan 1, 2011

By George A. Morgan

The successful expansion of crude oil production begun in late 1977, led to promising development of the nonfuel minerals sector. Although actual production of nonfuel minerals was limited both in variety and in percentage of output on a world scale, the potential for expansion with a rapidly developing infrastructure was significant. The energy base was expanding with construction of two new hydroelectric powerplants in addition to the existing plant near Edea. The Song Loulou plant will have a 240-megawatt capacity, and a hydroelectric plant under construction in the northern part of the country by mainland China will have 72 megawatts of installed capacity. Inflation of between 15% and 20% resulted in a real gross domestic product (GDP) of $2.8 billion2 in fiscal year 1980 (July 31 to June 1), up 6% from that of the previous fiscal year. Petroleum became the leading export item in terms of value, surpassing coffee and cocoa exports. Mineral exports as a whole increased eightfold in value, mainly because of oil sales. Oil exports also caused a reduction in the trade deficit by nearly one-third, and the Government expected its 1980-81 budget to be balanced at $1.17 billion. The Port of Douala accounted for about 8 million tons of cargo, or 93% of total maritime traffic for Cameroon. Expansion plans for the port call for an initial increase to 5 million tons, and a cargo handling capacity of 7.5 million tons in 1985 and 10 million tons by 1990. The Port of Victoria will gain importance with the startup of an oil refinery. The country's third seaport at Kribi was used solely for timber shipments, and capacity at the Port was to triple by 1981. The Government operated its own shipping line with six oceangoing freighters. France was the dominant trading partner, accounting for 25%

Jan 1, 1982

By Will Callupe Arzapalo

The success of the minimization of blast induced-damage at Barrick?s Pierina Mine in Peru is the result of an effective working relationship between Mine Operations and the Geotechnical Services Department. A detailed design criteria manual is used to match the blast plan to the site?s varying rock types and slope designs. The Geotechnical Services Department has further developed a comprehensive pre- and post-blast checklist that is critical to the drilling and blasting process as it pertains to wall stability. Wall control blasts are evaluated with quality assurance field checks, vibration monitoring and frequency control, video assisted performance quantification and post excavation face profiling. These detailed observations are compiled and summarized in a blast performance evaluation that is considered to be an ?Industry Best Practice?. The information and detail provided by each performance summary allows accurate blast analysis and effective design refinement.

May 1, 2006

By Ian Hutchison, Ted Sluder, Jack Caldwell, Don Moore

Introduction The Cannon mine at Wenatchee, WA has recently been brought into operation to recover gold from the sandstones of the Swauk formation. The mine is a joint venture between Asamera Minerals (US) Inc. and Breakwater Resources. A tailings impoundment was constructed to impound 2.7 to 3.6 Mt (3 to 4 million st) of tailings at 1.8 kt/a (2000 stpd) over about five years. This paper describes the design and construction of the impoundment. In particular, it describes the 100 m (300 ft) high earthfill embankment that is the main feature of the facility. Project environment The project is located on the outskirts of Wenatchee, a town of about 40,000 people. The town is situated on the flat alluvial terraces beside the Columbia River. The Cascade Mountains rise from the terraces in a series of ridges and valleys. The mine is at the foot of the Cascades. The tailings impoundment is in one of the steep valleys. The climate is mild and dry (Table 1). Site selection Twelve alternative sites within a 16-km (10-mile) radius of the mine were examined. Decision making theory was used to select the most suitable site. Advantages of the chosen site include its proximity to the mine and its low visibility from points of common public access. Also, the area was already heavily impacted by an existing silica quarry. The major disadvantage of the site is the need to pump tailings over a distance of 1.5 km (1 mile) and against a static head of 200 m (655 ft). Also, it is located in a gulch just upstream from the town of Wenatchee. Site geology The impoundment is generally underlain by interbedded sandstones and siltstones. The siltstones are often shattered. The sandstones are often friable. Both rock types are extensively jointed. Some isolated faulting of the sediments occurred before the area was covered with basalt flows. About 10,000 years ago, at the end of the ice age, the basalts were covered by 3 to 10 m (10 to 33 ft) of wind blown loess - a fine sandy clay and silt. River deposits filled the base of the valley to depths between 5 and 25 m (16 and 82 ft). Under the main part of the embankment, these materials were removed to expose bedrock. Ground water flow is generally through the more permeable layers. The permanent water table is about 5 m (16 ft) beneath the ground surface. Project and impoundment layout Figure 1 shows the layout of the mine, the mill, and the tailings impoundment. The tailings deliv-

Jan 8, 1986

By Tiezheng Li

Keywords: Laminate Composites; Mechanical Behavior; Damage Evolution The mechanical performance of Ti-6-4-Al3Ti metal-intermetallic laminate (MIL) composites synthesized by a reactive foil sintering technique was evaluated. Crack morphology of untested Ti-6-4-Al3Ti MIL composites has been characterized by optical microscopy. Mechanical tests were performed on Ti-Al3Ti metal-intermetallic laminate (MIL) composites and pure Al3Ti, and the principal mechanisms of damage initiation and accumulation were identified experimentally. The elastic properties and anisotropy of the laminates were calculated and successfully compared with Resonant Ultrasonic Spectroscopy (RUS) measurements. The effect of residual stress on the fracture toughness of the Ti-6-4-Al3Ti MIL composites was analyzed.

Jan 1, 2005

By A. L. Sweetser

EXPERIENCE has shown how difficult it is to obtain information regarding laboratory-tests in connection with the chlorination-process for the extraction of gold from its ores, and I therefore present the following method, somewhat in detail, for the benefit of those who may desire to pursue research work in this field. The ore chosen was a partly-decomposed porphyry, extremely siliceous and comparatively soft, and of an average value per ton of from $25 to $26 in gold and $0.68 in silver. The chemical analysis gave : Fe2O3, 3.35; FeS, 1.5; MnO2, 0.75; ZnCO3, 4; Al2O3, 3.20; H2O, 0.7; SiO2 and insol., 83.50 per cent. The ore, first crushed to pass a 5-mesh screen, was coned and quartered until a 45-lb. sample was obtained. Samples for assay and analysis, taken from this lot by means of riffles, were crushed to pass a 100-mesh screen. The original sample was divided into 10-lb. lots, of which one was crushed to pass a 10-mesh screen; another through a 12-; the third through a 20-, .and the last through a 30-mesh screen. Because of the production of an excessive quantity of fine material it was deemed inexpedient to crush finer than 30-mesh size-a decision the wisdom of which is proved by the data in Table I., showing the increasing ratio of slimes, in proportion as the ore is crushed finer. In order to determine the percentage of fines in the sizes of mesh selected, a weighed sample of ore was taken from each mesh, and a sample from the 10-mesh lot was passed successively through 20-, 40- and 100-mesh screens, and the percentage remaining on each screen determined. This process was repeated with the 12-, 20- and 30-mesh lots, with the results given in Table I.

Sep 1, 1907

By H. J. Sloman

Mining laws of the several coal-producing Stat e with respect to safety catches on mine cages and their testing are extremely variable and generally indefinite in scope. The most specific requirements are contained in the Coal Mining Laws of Washington,3/ as follows:

Jan 1, 1944

By Michael Drozd

"The operation of an activated charcoal system has five separate unit operations. These unit operations have common points for CIP, CIL and CIS system, which vary widely in application.The unit operations are:a. Absorptionb. Desorption (Stripping)c. Acid Washingd. Reactivatione. Carbon Handling (carbon transportation, sizing, dewatering, etc.)Cost optimization starts with the basic operating parameters (design philosophy) set down at the time of engineering design. These parameters undergo almost immediate change due to site specific ore requirements, throughput changes, operator requirements or reagent availability.Activated charcoal is sometimes viewed as simple, uncomplicated reagent that requires not optimization. To some extent, this statement is true, but under most circumstances, if the time necessary to optimize the use of activated charcoal is available, the effort is rewarded with significant savings. CPL-Carbon Link has embarked upon a program of supplying technical support with its activated charcoal. Several operations in the United States have undertaken to have CPL-Carbon Link do an operational survey to determine if potential savings are possible. CPL-Carbon Link has offered to do these surveys for projects that are clients or simply would like to have CPL-Carbon Link review their operation. The information accumulated by CPLCarbon Link is being used to attempt to fashion industry standards so that a common reference point can be established for activated charcoal usage."

Jan 1, 2008

Samples weighing 0·5 g are decomposed with hydrofluoric and other acids. Most elements are extracted ftom the acid, aqueous solution by Alamine 336 (tricaprylyl tertiary amine) and thorium is determined in an aliquot taken from the aqueous phase by means of its reaction with arsenazo III. Concentrations down to 4 p.p,m. may be determined at a rate of 100 samples per man-day of 8 hr.

Jan 1, 1971

By Philippe Poirier

Les parcs à résidus miniers représentent un risque environnemental qui nécessite une gestion adéquate. Suite à la publication du « Guide sur la gestion des parcs à résidus miniers » en septembre 1998, les membres de l?industrie minière ont appliqué les éléments de gestion du Guide, permettant ainsi une amélioration continue des opérations. En février 2000, l?industrie minière a indiqué le besoin d?établir des lignes directives plus spécifiques pour l?opération sécuritaire des parcs à résidus. Dans cette optique, l?Association Minière Canadienne a publié, en septembre 2002, un Guide pour l?exploitation, l?entretien et la surveillance (EES) des parcs à résidus miniers. Suite au développement du Guide et à son application sur plusieurs sites miniers, il apparaît que la mise en oeuvre d?un Manuel ESS des parcs à résidus miniers permet : ? d?établir les responsabilités des intervenants; ? de s?assurer que les critères d?opération sont appliqués; ? de mettre en oeuvre le plan de déposition des résidus et de gestion de l?eau; ? de rencontrer les normes et exigences environnementales; ? de définir un programme d?entretien et de surveillance des ouvrages; ? d?identifier les risques et de mettre en oeuvre un plan d?intervention d?urgence; de démontrer une opération diligente.

Nov 1, 2002

During the period 1979 thru 1982, Multi Mineral Corporation conducted a mining research program at the United States Department of the Interior's Bureau of Mines Oil Shale Mining Environmental Research Facility in the Central Piceance Creek Basin, Rio Blanco County, Colorado. The program consisted of mining, environmental and geotechnical research data and the results are described in this report.

Jan 1, 1983

By Jilai Xue

Experiments with various industrial cathodes ranging from 35 wt.% to 100 wt.% graphitic and fully graphitized carbons were carried out in a laboratory aluminum electrolysis cell. Sodium and cryolite bath penetration into the cathode samples was measured by XRD and SEM-EDS analysis. For a higher cryolite ratio in the bath, the cathodes with lower graphitic carbons exhibited more sodium penetration than the fully graphitized. The increased graphitization in the cathode materials can reduce Na, NaF and Na3AlF6 penetration. SEM-EDS inspection reveals that the sodium and fluorides penetration within the cathode samples has different patterns for varying graphitization of the carbon materials. XRD quantitative analysis indicates that there is a large percentage of Na3AlF6 in the penetrated bath. The results can provide useful information for quality evaluation of the industrial cathode products.

Jan 1, 2010

Approximately half of all the fuel energy used in the United states is now pro-vided by oil and natural gas. A persistent and rapid growth in energy demand during the last 3 decades has been absorbed largely by the liquid and gaseous rather than solid fuels. In 1948 the energy provided by coal was substantially the same as in 1920. Meanwhile, the use of oil and natural gas each had increased fivefold. On a per capita basis, the change is more significant. Coal consumption has dropped from about 6 tons per person to 4-1/2 tons, while oil has increased from 4-1/3 barrels to 14-1/3, and natural gas from 7,500 cubic feet to about 35,000. These facts would have only academic interest if the United States had unlimited supplies of all fuels. However, while the Nation's reserves of coal are adequate to meet our needs for centuries, those of oil and natural gas appear limited. It is obvious, therefore, that the security of our liquid-fuel position would be greatly enhanced if the supply could be based in an increasing degree on solid fuels, such as coal and oil shale, which make up more than 95 percent of our fuel reserves, instead of natural oil and gas. In addition, this would create new employment and help to stabilize the market for coal, which may be facing comparatively bleak prospects in the near future unless its position with respect to other fuels is improved.

Jan 1, 1950

By AIME AIME

LOCAL COMMITTEES. GENERAL RECEPTION COMMITTEE.-Mr. and Mrs. H. S. Chamberlain, Mr. and Mrs. J. T. Lupton, Mr. and Mrs. T. H Lasley, Mr. and Mrs. R. S. Faxon, Mr. and Mrs. H. Clay Evans, Mr. and Mrs. C. E. James, Mr. and Mrs. B. F. Thomas, Air. and Mrs. H. S. Probasco, Mr. and Mrs. W. M. Lasley, Mr. and Mrs. L. W. Llewellyn, Mr. and Airs. T. G. Montague, Mr. and Mrs. E. B. Thomasson, Mr. and Mrs. C. F. Milburn, Mr. and Mrs. C. A. Raht, Mr. and Mrs. C. C. Notting¬ham, Mr. and Airs. Z. C. Patten, Mr. and Mrs. Willard Warner, Mr. and Mrs. S. R. Read, Mr. and Mrs. Carl White, Mr. and Mrs. M. M. Allison, Air. and Mrs. C. E. Buck, Mr. and Airs. H. F. Temple, Air. and Mrs. M. M. Hedges, Mr. and Airs. X. Wheeler, Mr. and Airs. John A. Patten, Air. and Airs. N. T. Montague, Mr. and Mrs. R. H. Williams, Mr. and Mrs. T. R. Preston, Mr. and Airs. Morrow Chamberlain, Mr. and Airs. T. C. Thompson, Mr. and Airs. T. L. Montague, Mr. and Mrs. O. L. Hurlbut, Air. and Mrs. C. A. Lyerly, Mr. and Mrs. Garnett Andrews, Air. and Mrs. M. B. Ochs, Mr. and Airs. Webster James, Mr. and Mrs. D. P. Montague, Mr. and Mrs. Z. C. Patten, Jr., Mr. and Mrs. W. A. Sadd, Mr. and Mrs. J. B. Pound, Air. and Mrs. George D. Lancaster, Air. and Airs. J. F. Johnston, Mr. and Mrs. R. W. Barr, Air. acrd Mrs. W. B. Davis, Mr. and Airs. Douglas Baxter, Air. and Mrs. W. R. Crabtree, Mr. and Mrs. Lewis M. Coleman, Mr. and Mrs. Newell Sanders, Mr. and Mrs. E. Y. Chapin, Mr. and Mrs. W: B. Riddell,. Mr. and Mrs. J. B. Frazier, Mr. and Mrs. John A. Moon, Mr. and Mrs. C. D. Mitchell, Dr. and Airs. J. H. Race, Mr. and Airs. A. W. Chambliss, Mr. and Mrs. J. P. Smartt, Mr. and Mrs. J. F. Tarwater, Mr. and Mrs. L. D. Drewry, Capt. and Mrs. A. B. Putnam, Mrs. Minnie C. Ewing, Mr. G. F. Meehan, Mr. Sam S. Gerstle, Mr. P. A. Brawner, Mr. C. M. Preston, Air. George M. Guild, Mr. L. M. Mansfield, Dr. J. W. Johnson, Dr. J. AI. Hogshead. EXECUTIVE COMMITTEE.-H. S. Chamberlain, Chairman; H. S. Probasco, C. M. Preston, H. Clay Evans, J. T. Lupton, M. B. Ochs, C. C. Nottingham, Al. Al. Alli¬son, R. S. Faxon, C. E. James, C. A. Raht. EXCURSION TO CHICKAMAUGA PARK.-T. C. Thompson, Chairman; B. F. Thomas, G. F. Meehan, Morrow Chamberlain, W. J. Bass, J. K. McGoodwin. EXCURSION TO HALES BAR LOCK AND DAM.-R. H. Williams, Chairman; John A. Patten, Newell Sanders, George M. Guild, Capt. A. B. Putnam. EXCURSION TO ROCK-WOOD.-F. H. Clymer, Chairman; T. L. Brown, T. A. Wright, J. P. Tarwater, T. L. Peterman. INSTITUTE HEADQUARTERS.-The Hotel Patten. THE first session, held Thursday evening, Oct. 1, in the Banquet Hall of the Hotel Patten, was called to order by Capt. H. S. Chamberlain, Chairman of the Local Committee, who, in behalf of the city of Chattanooga, extended a hearty welcome to the members and guests of the Institute.

Nov 1, 1908

By Garry Johansen, Andrew McCallum, Sandy Gray, Gary Patrick, Jennifer Abols

"The authors challenge the traditional thinking that whole ore cyanidation followed by Carbon in Pulp (CIP) or Carbon in Leach (CIL) should be applied as a standard process in the majority of gold processing flowsheets. The concept of whole ore leaching by using cyanide can result in unnecessary environmental and capital risk. Alternative, currently available technologies can be used to provide the desired level of gold recovery at a much lower installed cost and less impact on the environment. Gravity concentration, alone or in conjunction with flotation, can produce a gold bearing concentrate that can then be fed directly to a batch or continuous intensive cyanidation unit.The InLine Leach Reactor (ILR) is an intensive cyanidation unit developed by Gekko Systems of Australia. Advantages of this technology include significantly reduced capital outlays for greenfield plants or plant upgrades and increased investor returns. Reduction of onsite cyanide and carbon inventories improves plant safety, materials handling and site security. By using direct electrowinning to treat the gold bearing solutions produced by the ILR, the need for a conventional carbon stripping circuit is removed. Potential also exists to increase grind size – saving energy, further reducing capital and operating costs and decreasing the environmental impact of a mill. Detoxification of cyanide before the release of solution to the tailings dam can minimise tailings disposal and containment requirements.When used in the right application the proposed process will have little or no impact on gold recovery and may actually increase recovery for complex ores. Areas applicable to this type of treatment include: plants in environmentally sensitive regions, lower tonnage higher grade deposits, coarse gold deposits, and preg robbing ores - some of which may not currently be economically feasible using standard processes and flowsheets. We have provided three examples of such projects, where an alternative to whole ore leach and CIP or CIL has delivered these benefits."

Jan 1, 2003

By G. G. Roy, R Shekhar

Pachuca tanks are extensively used for the cyanide leaching of gold and the carbonate leaching of uranium, processes in which oxygen mass transfer plays a very important role. Experiments were carried out to clarify the effect of design and operating parameters on oxygen mass transfer. Parameters such as the ratio of tank height to tank diameter, the ratio of draught-tube diameter to tank diameter and the tank design were found not to influence oxygen mass transfer. Results also showed that equal superficial gas velocities may be used as a criterion for scaling up oxygen mass transfer in both full-centre-column and free-air-lift Pachuca tanks with clear water. A volume-averaged, volumetric gas-liquid mass-transfer coefficient (k'av) was used to characterise oxygen mass transfer in full-centre-column tanks. The axial dispersion model was used to determine k'av. The resulting model used only tank geometry and air flow rate as inputs for the prediction of k'av in industrial-scale tanks. Predictions from the model show clearly that "local" mass-transfer coefficients, measured at one or two locations, may not adequately represent gas-liquid mass transfer in industrial tanks. It is therefore necessary to obtain an estimate of k'av

Jun 18, 1905