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By Luis Enrique Vargas V.

A medida que la tecnología minera en equipos de extracción de material de gran tamaño avanza, el minado de material volado y/o disparado crece notablemente y la excavación a taludes finales son realizados en menor tiempo. Este trabajo se enfoca en recomendar mallas y cargas, que minimicen o reduzcan el daño en las paredes del talud, ya sea por vibración provocado por las voladuras, o por el proceso de minado en la mina Toquepala.

Sep 1, 2017

By Whang K, Choi H

A study of flocculation of ultra-fine coal particles by ultrasonic waves was investigated on a laboratory scale.The coal suspension was dilute, with low ionic strength, and at pH 6·2.When a stationary sonic wave is set up in a solution containing suspended coal particles, it is believed that high and low pressure regions are alternately established at the half wave-length of the sonic wave and this resultsin the migration of coal particles towards the low pressure regions.As expected the flocculation is more effective as to frequency and the power of the ultrasonic waves is increased.The shape and size of the test equipment are also important variables.

Jan 1, 1977

By R. V. Ramani

This volume is the fourth of a four-volume final report on research carried out under a contract from the U.S. Bureau of Mines on the development of a computer simulation model for surface mine reclamation planning. The other volumes are titled as follows: Volume I: Ore Reserve Estimation, Volume II: Dragline Model, and Volume III: Mine Coordinate Generator System. The Open Pit Materials Handling Simulator (OPMHS) was first developed" in 1971 and modified and updated in 1975. The present work is an update of the 1975 version and provides a direct link between the geology and reserves system and the various activities of the mining equipment in a mining system. Also, the modeling techniques in OPMHS/2 have incorporated a flexible method for describing various equipment (shovels, trucks, belts, trains, etc.), locations, their sequence of operations, place changes, and their interactions. These features allow for studying mining equipment selection, mining method analysis and reclamation planning. This report describes the Open Pit Materials Handling Simulator Version 2 (OPMHS/2). The report details the program features, operation, and application. Through an extensive set of appendices, the data input sequence, input variable definitions, sample data listing and program output are presented in detail.

Jan 1, 1985

By Carnevale Francesco, Bracci Laudiero Alberto, Pampanin Piero

"SummaryIn the Port of Naples a slurry wall has been realized through a sandy layer up to a deep tuff layer using the Cutting Soil Mixing technique.The executed panels have dimensions of 2.8 m x0.65 m in plan and a total length of 25 m. Primary and secondary panels have been executed using the wet to wet technique. During the panels execution the following parameters had been measured: injection pressure, injected volume, verticality. At the end of the works an exploratory campaign has been carried out through boreholes collecting samples for laboratory tests in order to verify the diaphragm thickness and its physical and mechanical properties (i.e. unit weight, unconfined compressive strength).The interpretation of the collected data allowed to verify the efficiency of the method, the volume of slurry loss due to permeation during the panels execution, the quantity of the obtained spoil compared to the volume balance equation, both for the sand and the tuff layer.Eventually, the measured physical and mechanical characteristics of the panels have been correlated to the execution method performed.IntroductionIn the Naples Port area there is a polluted site which has to be hydraulically isolated in order to prevent the pollution of the groundwater that flows from land to the sea through the Port area. A hydraulic cut-off wall has to be realized and particularly a slurry-wall realized using the CSM method had been executed.To date, two stretches have been executed, 140 an 110 m in length respectively, as shown in Figure 1 and Figure 2.After execution, the slurry-walls have been investigated with boreholes. In-situ and laboratory tests on the recovered samples of grout have been carried out; furthermore, the geotechnical parameters of the mix composing the wall have been measured."

Jan 1, 2014

By M. Visser

Keywords: Pyrometallurgy, furnace, ferrochrome, Samancor, ferrochrome process Samancor Chrome has been, and continues to be, a major player in ferrochromium production. The company has a proud history and possesses benchmark technology and operations. Currently five business units are operating: two sets of mines and three smelter plants. Samancor Chrome produces around one million tons of charge chrome annually. Chrome ore, intermediate-carbon ferrochrome, and low-carbon ferrochrome, form part of the portfolio. Electrode paste is also manufactured through a joint venture with Highveld Steel and Vanadium. Samancor Chrome has a balanced approach towards operational strategy, and has entered into a number of joint venture partnerships. Through its access to quality raw materials, knowledge, and experience of various production technologies, and its strategic abilities, Samancor Chrome is well positioned to reap the benefits from opportunities in the current and future industry context.

Jan 1, 2006

IF a straight line should be drawn on the map (See 1, page 96) through the northern half of the South Island of New Zealand, from Mt. Domett in the north to Arthur's Pass in the south, and another line drawn parallel to it and at a distance of ten miles to the west, according to the topographic scale, it will be found that within the belt thus drawn across the country all the most important mines, past and present, of the South Island are situated, with the exception of a few in Otago.The most important product of this tract being gold, and Reefton, the most important southern mining field, being situated at about its central portion, the zone may aptly be termed "The Great Reefton Gold Belt." The occurrence of so many gold mines along this particular strip of country is not at all a matter of chance, but is the outcome of cause and effect. Running along the eastern side of the gold belt are the Brunner and Victoria Ranges, which are chiefly composed of crystalline schists and metamorphic granite of probably Cambrian or Silurian age; between these and the gold-bearing series there are interposed at one or two places some beds of slates, limestones, and...

Jan 1, 1910

By Laurence G. Trudell

Geology and oil-yield data are presented for a 58-square-mile area encompassing the U.S. Department of the Interior oil-shale leasing program tracts in the western Washakie Basin, Sweetwater County, Wyo. Lithology and oil yields of samples from three Bureau of Mines coreholes are evaluated and correlated with Kinney Rim surface sections measured and sampled by the U.S. Geological Survey. Minable sections of oil shale averaging up to 25 gallons of oil per ton crop out on Kinney Rim in the Laney Member of the Green River Formation. Thick oil-shale sections in the Laney Member that average 15 gallons per ton represent 155 million barrels of oil in place per square mile. In the lower part of the Green River Formation the Tipton Shale Member contains a 20-to 40-foot section averaging 15 gallons per ton. Beds of high-volatile C bituminous coal up to 6 feet thick are present in intertongued parts of the lower Green River Formation and upper Wasatch Formation.

Jan 1, 1973

By É. Roberge, S. Makni, G. Gagnon, F. Lavoie, A. Faucher

"Feed particle size is an important variable for the primary grinding mill operation. Several commercial vision systems have proven to successfully measure online many types of ores and are used for automatic control. However, due to limitations associated with segmentation algorithms, these systems fail to provide good measurements when the feed is composed of a specific bimodal particle size distribution: very big rocks and a large amount of fine particles. This is typically the case for crushed iron ore. This paper presents a technique to overcome the limitations of existing vision systems by using 3D cameras and appropriate processing methods. It provides online particle size distribution indicators and bulk volume flow rate measurement. It is designed to be very cost-effective, robust, precise, easy to install and to maintain. The 3D system was validated in two iron ore processing plants and the results clearly show that it can be used to optimize primary grinding mill operation where 2D segmentation vision systems fail.INTRODUCTIONFragmentation measurement using digital image processing has successfully been applied in mining and mineral processing operations. Several maintenance and operating applications are already deployed in the industry: Measurement of rock fragmentation after blasting (Maerz, 1999; Palangio, 1999) (Pragyan, 2012) Truck inventory (Palangio, 2005) Monitoring of crusher mantle wear Automatic control of crushers and SAG mills (Bouajila, 2000) (Bartolacci, 2001)Commercial technologies like WipFrag (Maerz, 1999), VisioRock and others proved to be very efficient to precisely measure the particle size distribution of many types of materials. These products are mainly composed of a camera, a lighting system and an image processing system based on a segmentation algorithm. By controlling adequately the lighting conditions and with periodic maintenance on the segmentation algorithm calibration parameters, it is almost always possible to achieve reliable measurements.However, the segmentation algorithm is not adequate when the particle size distribution contains big rocks and a large amount of fine particles. In this case, the area containing the fine particles is accounted as a big rock while big rocks get segmented as multiple smaller sized particles, leading globally to a wrong measurement. This situation prevails for crushed iron ore and coke, among other materials. Figure 1 shows a picture of a material which is typically very difficult to process through segmentation techniques."

Jan 1, 2015

By L. Salnais

"Aluminum alloy structural components f or aircraft designed prior to the early 1970s, were machined from 2024, 7075 and 7079 plate, bar and forgings in either the T3xxx of the T6xxx tempers. Protective treatments for these parts consisted of chromic acid anodizing and alkyd zinc chromate primer, plus a nitrocellulose lacquer for exterior parts.The major service problem with these parts was the frequent occurrence of exfoliation corrosion and stress corrosion cracking (S. C. C.). Therefore, 2024 and 7079 alloys, with min or exceptions, were not used in aircraft designed after the early 1970s. Replacement materials were 7075 and 7050 alloys in the overaged, exfoliation corrosion and S. C. C. resistant, T73xxx tempers.The use of improved materials together with the upgrading to chromated epoxy primers, polyurethane enamels and the introduction of water displacing corrosion inhibiting compounds have significantly reduced corrosion in aircraft. IntroductionThe prevention of corrosion in aircraft has been a challenge to aircraft designers for many decades. With the design of the first all-metal aircraft, the designer and builder were thrust into the relatively new field of protective treatments as corrosion started to become more prevalent. This resulted from the continually increasing importance and wider utilization of aircraft, and their exposure to a wider variety of ho stile environments such as urban industrial pollution, high humidity tropical areas and salt ladened marine environments.Corrosion advanced another significant step when, after World War II, designs of new and larger aircraft utilized larger and thicker metal sections in the manufacture of structural components. With thicker mill products came higher residual heat treat, fabrication and assembly stresses resulting in an increased number of stress corrosion and exfoliation corrosion problems.Apart from the exterior environment, aircraft interior s can be exposed to a number of fluids which are either directly or indirectly responsible for corrosion. The most common of the fluids is water which is usually introduced as a result of condensation, especially in pressurized fuselages, and spillage from lavatories, galley s and electrolytes from batteries. These fluid s have a degrading effect on protective treatments and are also corrosive to the substrate metal. Fluids such as phosphate ester hydraulic fluids and ester based turbine engine lubricating oil s are not corrosive to the substrate metal, albeit they do contribute to corrosion by the degrading effect on protective treatments."

Jan 1, 1988

By D. V. Venugopal, W. W. Gardiner

Spessartine-quartz rocks are manganiferous sedimentary rocks rich in spessartine and quartz which occur in north-central New Brunswick. They represent a recrystallised manganiferous siltstone/chert that is contained in or associated with red manganiferous siltstone (RMS) units. The spessartine-quartz rocks and RMS form part of an Ordovician volcanic and sedimentary succession within the Appalachian-Caledonian orogen which hosts numerous massive sulphides and polymetallic vein deposits. The New Brunswick spessartine-quartz rocks are spatially and temporally associated with stratiform base-metal, precious metal and hydrothermal tin-tungsten deposits. This suggests that spessartine-bearing lithologies and zones can be useful in predictive metallogeny and for the understanding of the stratigraphy and palaeographic setting of the early Palaeozoic rocks of the Appalachian-Caledonian orogen.

Jan 12, 1992

Local conditions at Hatches Creek are described, together with the mineralogy, mining and treatment of tungsten ores, with particular reference to procedures adopted by Pimer Mines, N.L.The Hatches Creek tungsten field covers an area of about 20 square miles in: Central Australia; 285 miles' N.E. of Alice Springs. Access is by rail to Alice Springs, then by 200 miles of bitumen highway to Barlo Creek and 8,5, miles of bush track to the field. Passengers can also reach the mines by... A semi-desert climate prevails Rain; generally in the form of thunderstorms falls in the summer months: December to March. Average annual rainfall is approximately 15 inches but there is great variation from year to year, occasional droughts being followed by torrential downpours. Vegetation is sparse except in the wide creek beds. Surface water occurs in rock holes some of which, spaced miles apart, carry permanent water...

Jan 1, 1955

By Tom Gonzales

At San Manuel, AZ, Magma Metals Co. operates an Outokumpu flash furnace, four Peirce-Smith converters and two anode casting wheels that are supported by six anode vessels. Process gasses from the flash furnace and converters are treated in a two-train/ double-contact sulfuric acid plant. The plant captures 98% of the sulfur. A new flash furnace was commissioned in July 1988. It has since processed more than 2.7 Mt (3 million st) of sulfide concentrate without a major rebuild. The company has gained unique experience in the operation of the flash furnace at high oxygen enrichments with low off-gas dust loadings. New procedures have been developed to maintain secondary material generation at equilibrium and for maintaining metallurgical control of operating parameters. Process flow description At Magma's San Manuel plant, concentrates and other copper-bearing material are blended and conveyed from two separate areas of the plant to three 420 t (465 st) capacity wet charge bins located above the rotary dryer. Flash furnace silica flux is conveyed to a 227-t (250-st) capacity fine flux bin located adjacent to the wet charge bins. The concentrate and flux are blended in controlled amounts and fed into a 168-t/ h (185-stph) gas-fired rotary dryer. The wet charge enters the dryer at 8% moisture and is dried to 0.2% moisture. The dried charge is pneumatically conveyed to a 580-t/h (640-stph) dry charge bin located above the flash furnace. Flash furnace charge is drawn from the bin by two drag conveyors at a concentrate feed rate of 145 t/h (160 stph). The charge is mixed with enriched combustion air and injected into the furnace reaction shaft. In the reaction shaft, the charge is oxidized to form matte, slag and a rich SO, off-gas.

Jan 1, 1992

By G. Schuman

Variations in pyrite reactivity are known to exist within samples collected from different areas. Using samples collected from acid and non-acid sites, the relationship between the factors affecting pyrite oxidation and observed variations in pyrite reactivity was studied. Heavy liquid separations were used to extract the pyrite from nine pulverized rock, coal, and coal refuse samples. Simulated weathering tests were used to determine the degree of reactivity of the extracted pyritic material. Representative portions of each pyritic sample were analyzed for whole rock composition (including pyritic sulfur and neutralization potential), for elemental composition, and by x-ray diffractometry. The samples were also examined with reflected light microscopy to ascertain pyrite morphology distributions. Tests for the presence of iron-oxidizing bacteria were all negative indicating the leaching tests were conducted under abiotic conditions. The results of the simulated weathering tests permitted the partitioning of the samples into two groups based on positive or negative neutralization potential (NP) values. Determinations were then made to evaluate the degree to which a variety of factors, including temperature, partial pressure of oxygen and water, and crystallography affected pyrite reactivity. Multiple regression analyses showed no statistically significant relationship between degree of reactivity and elemental composition. However, for samples with negative NPs, a simple regression analysis showed a strong linear relationship to exist between the reactivity of the pyrite and the proportion of "unstable" pyrite (framboidal + mossy pitted) found in each extracted pyrite sample. Samples of pyrite with positive NPs, although producing acidity, did so in at least one order of magnitude less than the NP deficient samples, indicating the important role that NP plays in controlling pyrite reactivity. A simple linear regression between cumulative sulfate production and NP for the three samples with positive NPs had a correlation coefficient of 0.99. For the nine samples grouped together, a linear regression model between cumulative sulfate production and NP (both negative and positive) was established between log of sulfate and NP.

Jan 1, 1991

By D. Conklin

Annual fish monitoring of the Red River, NM from the town of Red River to downstream of Questa, NM has been conducted since 1997. This long-term dataset, sponsored by the Chevron Mining Inc. Questa Mine provides an opportunity to evaluate the fish community response to natural phenomena, such as landslides and drought. Hydrothermal scars are present on drainages to the Red River, which can contribute large quantities of sediment to the Red River during localized storm events. Sediment inputs from the hydrothermal scars result in decreased habitat and water quality conditions within the Red River. Landslides from the hydrothermal scars contributed large amounts of sediment to the Red River in the summers of 2002 and 2007. Resident trout populations in the Red River after summer 2002 were depressed at sites adjacent to and downstream of the hydrothermal scars. Resident trout populations had begun to recover by 2005 and 2006; however, after the summer 2007 landslide, the resident trout population was again drastically reduced. In fall 2007, 13 resident trout were collected from 11 sites in the approximately 23 km reach of the river, compared to 691 from the same 11 sites in fall 2006. Resident trout density and biomass has gradually increased since fall 2007, and flows have removed sediment from the study reach. A combination of increased sedimentation and decreased water quality were likely responsible for the decreased resident trout populations in the Red River. Drought and the lack of flushing flows appeared to exacerbate the problem of high sedimentation levels from 2001 to 2004. Climate models predict prolonged periods of drought and increased intensity of storm events, potentially resulting in less favorable conditions for the resident trout population of the Red River in this area.

Jan 1, 2011

By Don Welch

Pressures for change ?Land use constraints ?Project financing ?Local communities ?Environmental issues ?Sustainability requirements ?Stricter regulatory procedures ?Technical excellence ?Reduce risk ?Impacts of failure & non-compliance

May 1, 2010

By Moi Arzamendi, Jose Ramirez, Kenneth Kniss, Sunil Arora, James Gingery

Construction of a new approach embankment for a railroad bridge over a river in Southern California required placing up to 12 ft of fill over soft to medium stiff silts and clays along an approximate 1,500-ft long stretch. The embankment, situated within a narrow railroad right-of-way between an existing live track and existing buildings, would have been susceptible to excessive settlement that could damage existing buildings and numerous underground utilities if regular weight soil fill had been placed over the unimproved ground. To limit total and differential static settlements to tolerable levels, a design was developed using a combination of mechanically stabilized earth wall with lightweight cellular concrete fill and rigid inclusions ground improvement. This paper describes the design of the ground improvement system, construction methods used, and challenges of working next to live railroad traffic. Ground improvement quality control and assurance measures, and verification of performance by settlement monitoring are also addressed. INTRODUCTION AND BACKGROUND The 0.9-mile San Diego River Double Track (SDRDT) project is located on the Los Angeles-San Diego- San Luis Obispo (LOSSAN) Corridor in San Diego, California. The project includes the replacement of the existing 900-ft long single track railroad bridge over the San Diego River with twin double track structures. Construction of the project is phased and closely coordinated with the associated Mid-Coast light rail project (San Diego Trolley Blue Line Extension). The new bridge is a 7-span, twin steel, through girder structure supported by six cast-in-place reinforced concrete pier caps and two abutments. The large diameter cast-in-drilled-hole (CIDH) foundations are up to 9 ft in diameter, with upper portions encased in a 1.5-in.-thick permanent steel casing. The north abutment approach embankment includes a mechanically stabilized earth (MSE) retaining wall up to approximately 10 ft high and 1,520 ft long. This paper focuses on the design and construction of the north approach embankment. The project site is characterized by challenging geotechnical and seismic conditions. The site contains liquefiable soils interbedded with soft cohesive soils, underlain by competent layers of sand/gravel/cobble and other sedimentary formations. Static settlement of the new railroad, crossing utilities and adjacent buildings was a primary design concern for the north approach embankment.

Jan 1, 2018

By Carmel Bofinger, Maureen E. Hassall, David Cliff, Eric Stemn

Incident investigation is of utmost importance in most high-risk industries and is often used to improve organisational safety. This study was undertaken to examine the content of past incident investigation reports to determine the effectiveness of the incident investigations. The study uses a semi-quantitative method to assess the effectiveness of incident investigations in the Ghanaian mining industry by evaluating the quality of past investigation reports. The assessment tool consists of five elements with several indicators and rating scales for assessing the quality of an investigation report as a measure of the effectiveness of the investigation. The method was applied to 304 investigation reports of three Ghanaian large-scale gold mines, and the results correlated with incidence rates of the mines to determine if any relationship existed. The results showed that the mines differ significantly in the quality of their investigation reports, suggesting differences in the effectiveness of their investigations. In addition, the incidence rates of the mines negatively correlated with some elements of the assessment tool. In general, the method was found useful and revealed areas where improvement is needed.

By Mark G. Lafontaine

Underground 802.11 wireless communications has become widely adopted for automation and communication purposes but maximizing the wireless signal presents many obstacles given the harsh environment as well as the presence of materials and conditions that can reduce signal propagation. Changes in elevations and curvatures in ramp to drift transitions also affect the wireless signal. Based on the requirements of wireless applications such as voice, data, or location tracking, the wireless site survey is the key tool for measuring and predicting signal strength and signal-to-noise ratio. These readings help determine the maximum distance between access points in order to sustain an overlapping wireless signal where required. This paper describes the methodology and tools used for measuring 802.11 wireless signal strength in an underground mine environment in Northern Ontario. The physical characteristics of the mine and the actual recorded wireless signal data will be presented in order for the audience to gain an understanding of the factors that affect signal throughput. Antenna selection used for the site survey will also be discussed as it played a key role in propagating the wireless signal.

May 1, 2013

This paper describes a mobile laboratory developed specifically for nickel prospecting, and which was designed to be operated by sub-professional staff in remote areas independently of established laboratories. An atomic absorption spectrophotometric procedure was used to determine nickel, cobalt, lead, zinc, and copper ID latentIc and sulphIde samples, with a detection limit better than 25 µg/g for all elements. The procedure was applicable to both soil and drill samples and the accuracy of the procedure, which was ±5 per cent relative at the 1,000 µg/g level was sufficient for the preliminary assessment of mineralized samples and the control of drilling operations. The analytical procedure and the means taken to ensure the necessary reproductibility and accuracy are described. One operator can carry out 400 elemental determinations per 8-hr day at an approximate cdst of 6 cents per elemental determination. The results are returned within a single day, a factor which can contribute materially to the efficiency of drilling operations.

Jan 1, 1970

Interest in industrial minerals in recent years has increased to such an extent that it has taken them into the mainstream of the Australian mineral industry. Notwithstanding that time series data on the values of production, exports, and imports show that industrial minerals are overshadowed by metals and energy minerals, their contribution to the national economy is important and more significant than would seem to be indicated by the statistics. Whereas the ex mine value of metals generally includes some processing (at least to a concentrate stage), most industrial minerals are valued at little more than their extraction cost, in addition to which such costs are generally low because most industrial minerals are exploited in low-cost surface operations. Consequently, values of mine production of metals and industrial minerals are not strictly comparable in that values of mine production of metals tend to be overstated Short term growth of the industrial minerals sector is assured because of several new projects already commissioned but not yet reflected in the statistics. Longer term growth is also assured, based on various other major projects that are likely to come on stream in the early to mid 1990s.

Jan 1, 1989