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By Wedam Nyaaba, Samuel Frimpong, Bruno Ayaga Kansake, Irene Akalanyaba Ateng

Haul truck capacities have increased due to their economies of scale in large-scale surface mines. These high-capacity trucks impose dynamic loads on haul roads. A previous study estimated the dynamic forces imposed by ultra-large trucks on haul roads to be more than three times the static load. These dynamic forces exacerbate haul road stresses and deformation. Current haul road response models are 2D and use static truckloads for low-capacity trucks. No models capture the ultra-large truck dynamic effects on haul road structural response. This study uses 3D finite element (FE) modeling to compute the haul road response to ultra-large truck dynamic loading. The dynamic forces were modeled using multibody dynamics (MBD) in MSC.ADAMS. These forces were used in an FE model developed, verified, and validated in ABAQUS, to simulate the response of the haul road to the dynamic truck forces. The road was modeled using an elastoplastic Mohr-Coulomb model. The results showed that road deformation decreases with increasing layer modulus and increases with increasing payload. Increasing the base modulus from 100 MPa to 450 MPa reduced the maximum deformation from 258 mm to 62 mm. When the subbase elastic modulus increased from 100 MPa to 500 MPa, the maximum deformation decreased from 160 mm to 84 mm. Increasing the payload from 0 to 120% of the rated load increased the maximum wearing surface deformation from 131 mm to 216 mm. This study forms a basis for designing structurally competent haul roads for improving haulage efficiency and truck and operator health.

Jan 7, 2023

By Robert H. Peters

This U.S. Bureau of Mines report identifies the types of serious accidents that occur most frequently at small underground coal mines and describes the strategies that could help prevent these accidents. A wide variety of methods for improving safety are suggested, including improvements in the design of equipment, work procedures, work schedules, safety programs, and emergency response plans, as well as techniques for diagnosing the potential hazards associated with new technologies and work procedures. Some of the papers in this volume focus on preventing specific types of mining accidents-ones associated with materials handling (primarily back injuries), equipment maintenance, improper machine guarding, and ground failure during retreat mining. Although the recommendations in this volume are heavily influenced by research performed at underground coal mines in the Appalachian coalfields, most of the papers contain advice that is equally pertinent to almost any type of mine.

Jan 1, 1994

Gangue-cemented paste backfill (GCPB), is a well-established green mining technology and significantly improves the recovery rate of mineral resources, prevents mine dynamic disasters, reduces surface subsidence, and consumes a considerable amount of solid waste. The addition of an early strength agent as an additive in cement-based materials provides several security, technical, and economic advantages. In this study, the early strength agent on the early age (3, 7 and 28 days) strength of GCPB is evaluated experimentally. The GCPB specimens have an initial sodium sulfate early strength agent concentration of 0%, 1%, 2%, 3%, and 4%, and the obtained samples were analyzed by testing for uniaxial compressive strength (UCS) and scanning electron microscopy (SEM). The test results show that the UCS of the GCPB specimens with sodium sulfate is much higher than that of the blank specimens. When cured for 3 days and 7 days, the strength of GCPB with 2% sodium sulfate increased the most, by 131% and 116% respectively. When cured for 28 days, the strength of GCPB with 1% sodium sulfate increased by 135%. Scanning electron microscopy (SEM) results showed that the GCPB with 1% and 2% sodium sulfate had better internal structure compactness, thicker acicular crystals, and more flocs. As a kind of early strength agent, sodium sulfate can react with calcium hydroxide to generate calcium dihydrate sulfate and then react with calcium aluminate; the hydration product (C3A) quickly generates calcium sulfoaluminate hydrate (AFt) needle-shaped crystals, forming an early skeleton and improving the early strength.

Jan 7, 2020

By T. G. Paradis, C. A. Mohns

"This paper summarizes the Wren CAT (Clarifier and Accelerated Thickener) deep bed thickener operation at the EKATITM Diamond Mine in Canada’s Northwest Territories. EKATITMs’ thickener project is presented in terms of initial design considerations and present day operating practices. A circuit description summarizes process equipment, reagent systems, and typical process conditions, and details of Wren CAT operating principles are provided. Operating strategies are discussed, with emphasis on process instrumentation and control and operating challenges.INTRODUCTIONThe EKATITM diamond mine, operated by BHP Diamonds, Inc., is located in the Northwest Territories near Lac De Gras, approximately 300 km NNE of Yellowknife, NT. 9000 dry metric tonnes of diamond-bearing kimberlite ore are processed daily. Processing operations commenced in October, 1998.The EKATITM process plant flowsheet features typical steps in diamond recovery plant design. Figure 1 shows the general plant flowsheet. Size reduction and feed preparation are accomplished by crushing, scrubbing, and high pressure grinding rolls (HPGR) through closed-circuit classification with vibratory screens. Heavy medium separation (HMS) is used as the initial stage of heavy mineral concentration. Secondary concentration is accomplished in the recovery plant by attrition milling; wet, high-intensity magnetic separation (both wet and dry); and X-ray sorting.The present budget throughput rate is 9000 dry tonnes per day. This will be increased to 18,000 tonnes during the first ten years of operation. Unlike most kimberlite treatment facilities, which process material from a single ore body, EKATITM’s process plant was designed to accommodate ore from five different kimberlite pipes, each with its own treatment characteristics.All processing, except for primary crushing, is carried out in a temperature-controlled environment in the main process plant building."

Jan 1, 2000

Base metal skarns have provided most of South KoreaÆs Pb-Zn production since the end of the Korean War, with the bulk of production coming from the Yeonwha group of mines. Currently only the Kumho Zn-Pb mine remains in production, while magnetite skarns are mined as iron ore at the old Yomisan and Ulsan base metal deposits. Base metal skarns within Korea fall into two groups; those hosted in Cambro-Ordovician limestone sequences, situated mainly in sub-basins in the northeast of the peninsula and those hosted within carbonate volcaniclastics of the Cretaceous Gyeongsang Basin, in the southeast. Sulphide mineralisation is dominated by sphalerite, lesser galena, arsenopyrite and pyrrhotite, with subordinate chalcopyrite and molybdenite with Ag-Co credits. Skarns are composed of pyroxene-clinopyroxene-garnet-carbonate-quartz and magnetite, grading into silica-chlorite hornfels. Most of the significant deposits display both pipe-like and stratabound morphology. In the Hwanggang district, a zoned distribution of Ordovician carbonate hosted, polymetallic Mo-W and Zn-Pb-Cu-Ag base metal deposits is observed around the margin of a Cretaceous granite intrusion. Similar polymetallic zoning is recognised in the Sangdong district, where deposits include Sangdong (W), Abisan (Au-As) and Yomisan Northwest (Zn-Mo) and Yomisan Southeast (Zn-Cu-Co), hosted in Ordovician carbonates in proximity to Cretaceous quartz porphyry intrusives. The Taebaeksan district hosts the largest deposits at the Yeonwha group of mines. Although production ceased in 1993, significant resources remain, hosted in Ordovician limestone and dolomite that have been intruded by Cretaceous quartz porphyry dykes. Deposits in the Cretaceous Gyeongsang Basin consist of bedding concordant, vertically stacked base metal skarn mineralisation at several stratigraphic horizons, connected by carbonate-base metal veins with a pipe-like geometry. Evidence such as massive sulphide layers and restricted proximal carbonates suggest mineralisation was initially partly syn-depositional, with both base metals and carbonate venting onto a lake floor, being reconstituted to skarns by later magmatic activity. Skarn mineralisation is universally closely associated with the Cretaceous Bulgugsa Series acid intrusive activity. A common intrusive-structural relationship is recognised at some deposits, with bedding plane and imbricate thrust faulting, introducing felsic intrusives as sills. These intrusions probably introduced the base metals, carbonate, boron, heat and silica, which metasomatically reconstituted the carbonate lithologies to form skarn assemblages. The Korean base metal skarn deposits are regarded as Zn-Pb chimney-manto skarns and display similarities to the Mexican manto type deposits.

Jan 1, 1999

By M. Royker

Gold has been demonstrated as a possible catalyst for oxidation reactions. Some evidence for a possible promotion effect of platinum has also been recorded. The influence of platinum as promoter for Au/?-Al2O3 prepared via anionic ion-exchange for the oxidation of glycerol was investigated in a batch reactor at 60°C. It is inferred that the addition of platinum reduces the catalytic activity and the rate of deactivation, resulting in an overall higher final conversion of glycerol with increasing platinum loading. The addition of platinum to the catalyst favours the formation of the desired product, glyceric acid.

Jan 1, 2012

By Joni M. Barnes

A strain of Pseudomonas stutzeri isohted from selenium contaminated surface waters, was found to be effective . in reducing selenate (Se04 2) stoichiometrically to selenite (Se03 2 '), which was further reduced to elementaJ selenium (Se0 ). These reactions were concurrent with the microbial oxidation of lactate. In order to assess quantitatively the amounts of seilenate and selenitein solution, improvements to existing analytical methods (ion exchange chromatography and inductively coupled plasma atomic emission spectrophotometry technique) .were made.

Jan 1, 1991

By H S. Shin, H Jin, B H. Ryu, J Lee

Prospecting ice on the Moon necessitates drilling systems to obtain subsurface samples and measure the composition of ice deposits. Landers and rovers equipped with drilling equipment are essential for analysing ice and subsurface resources located at the Moon’s poles. These devices must be small, lightweight, low-power, highly efficient, and high-performance units to function properly in the extreme conditions of the lunar environment. Researchers have developed a prototype drilling apparatus capable of operating in atmospheric and cold environments. A newly developed drilling system in Korea, capable of performing not only sampling but also subsurface investigation, is introduced.

Sep 1, 2024

By Recepoglu O, Tolun R, Yavasoglu N, Bulutcu AN

Scheelite was floated from a low-grade (0.28 per cent W03) calcitic (96.30 per cent CaCO3) scheelite ore using oleoyl sarcosine as collector and alkylated 8-hydroxyquinoline as modifier. Compared to oleoyl sarcosine alone, the grade and the recovery of scheelite concentrate were increased from 8.07 per cent to 33.54 per cent and from 55.1 per cent to 73.4 per cent, respectively. Infrared studies with pure calcite and scheelite minerals showed that while alkyl oxine is adsorbed on the scheelite surface, it is not adsorbed on the calcite.

Jan 1, 1993

By John Chadwick

In the drive for faster development advance rates, railbound systems can be advantageous, in the right application. Skanska BS, the contractor to mine-owner VSK Mining, is driving an adit access deep into the Volouské Urchy Mountain in Slovakia to access the Gemerská Poloma talc deposit, some 70 km (43 miles) west of Ko?ice, the economic and cultural center of eastern Slovakia. Skanska began driving the Stolna Elisabeth drift in February 2007, extending 25 kg/m (50 lb/yd) rails (with 750 mm or 30 in. between sleepers) into the mountain to provide the main haulage to bring talc ore and waste out of the new mine once it gets into production. It will also be used for personnel transport, and is now almost complete. As a second egress and for ventilation, a 2.5-m- (8.2-ft-) diameter shaft of about 300-m (984-ft) depth will be sunk from surface down into the orebody. Stolna Elisabeth is a 4.2-km- (2.6-mile-) long drift mined at a cross section of some 11 m2 (118 sq ft). The finished profile is 3.2-m- (10.5-ft-) wide by 3.6-m- (11.8-ft-) high. It has been developed on a very slight incline so that water runs down it to the portal. The portal is 450 m (1,476 ft) above sea level and the end of the tunnel is 475 m (1,558 ft) above sea level. Much of the rock through which it has been developed is magnesite with a compressive strength of 150 MPA. The drilling jumbo is an Atlas Copco twin-boom Boomer 282 Raildrill drilling 42- to 45-mm- (1.6- to 1.7-in.-) diameter holes to a maximum length of 2.5 m (8.2 ft), depending on ground conditions. This is a drill jumbo that Skanska has used successfully on a number of projects during its life. The condition of the rock through which this drift has been driven is extremely variable. Five classifications of A1 and A2 and B1, B2 and [ ] B3, where A1 is the most competent rock and B3 is the worst, have been established. The amount of support used, of which more later is determined by the classification of ground conditions. At the time of the author?s visit, the project it was about 40 days ahead of schedule, thanks to high advance rates. For instance 6 m/day (20 ft/d) was the plan for the advance to be achieved in B1 rock, but sometimes the crews have achieved 8 m/day (26 ft/d) ? which is the average for the whole project ? in those conditions. In A1 the best advance rate achieved is 12 m/day (39 ft/d). The loading unit is a Häggloader 9HR-B on crawler tracks with a pony track to run on the rails. This allows the unit to be towed up and down the drift along the rails. To load from the face, the Häggloader lowers the foot of its onboard conveyor system to the floor and the backhoe pushes material on to it. This digging arm-conveyor combination produces uninterrupted, optimal volume loading of the haulage unit, without spill ? a technique offering load capacities as high as 180 m3/h (6,356 cu ft/hour). Further-more, as an electrically powered machine, it offers great

Jan 1, 2009

By N Haque

Base metal ores contain low levels of toxic/hazardous elements such as arsenic, antimony, bismuth, cadmium, lead and mercury. Given the large tonnage of base metal ores mined and processed each year globally, the accumulated mass of minor elements introduced into the biosphere is large and could be expected to have a significant environmental impact. Life cycle analysis (LCA) is a methodology that has been developed to assess the environmental impacts of material supply chains over their entire life cycle. Assessing the toxicity impacts of metallic wastes and incorporating these impacts into LCA methodology is not a simple task given the complexity of the issue. However, research and methodology development is in progress internationally to address this. Despite limitations concerning the lack of a coherent framework for characterising the toxicity impacts of metals, including issues such as bioavailability, a study was carried out to give first estimates of the relative toxicity impacts of various waste streams from metal production processes. The wastes considered were: red mud; sulfide tailings (copper, nickel, lead/zinc); lead/zinc slags; synthetic rutile residue; iron oxide residue; and copper slags and anode slimes. These toxicity estimates can be considered the æworst caseÆ scenario for these wastes, where all the metals present are bioavailable. Combining estimates of the amounts of the various waste streams produced in Australia each year with the toxicity results showed that despite their relatively low human toxicity impact per unit mass compared to some other waste streams, red mud and the various sulphide tailings had the highest annual human toxicity load on the environment, along with copper smelting slag and dust. Data from the pH dependent leaching test reported in the literature were assumed to represent first approximations of metal bioavailability and used to compare the two approaches to estimating the toxicity impacts of red mud.

Jan 1, 2009

By BURCU NILGUN CETINER, Serdar Aktas

Antimony has been used extensively in industry and in everyday life since the 19th century, and antimony sulfides have been known since around 4,000 B.C. Antimony’s most significant applications are as a flame retardant in the manufacture of electronics and textiles, as a catalyst for plastic fabrication, and as paint pigment and fining agent in glassware, opacifier in ceramics and an alloying element in ammunition and battery manufacturing plants. It is also used in vehicle brakes and tires. Brake pads contain stibnite (Sb), the sulfide compound of antimony. In particular, stibnite is used in automobiles as a lubricant, vibration reducer and friction stability improver. Anthropogenic activities are the primary source of antimony in the atmosphere [1,2]. Annual global consumption of antimony has increased to more than 1.4 × 105 t, and China is the most significant producer [2].

By J. E. Tiffany, Z. C. Gaugler

An active list of permissible explosives was published in December 1943 as part of the Bureau of Mines Report of Investigations 3736 under the title "Active List of Permissible Explosives and Blasting Devices Approved Previous to June 30, 1943." This list included 180 brand names. Changes in the list that have been authorized to December 31, 1945, placed 10 additional brands of permissible explosives on the active permis- sible list as a result of tests and changes in brand names.. Twelve permis- sible explosives were transferred from the active. to the inactive list. The present list contains 178 brand names. The brand names of the permissible explosives placed on the active list are as follows: American 3-A By test. Apcol No. 1-B Do. Black Diamond No. 11-B DO. Black Diamond No. 55 DO. Coalite G-1 DO. Coelite K-1 Do. Do. Coalite L-1 Coalite IS-1 Columbia B-2 DO. By change in name. By test. Monobel AA The permissible explosives transferred from the active to the inactive list are as follows: Anthracite B, L. F. Big Red No. 8 Independent No. 1, L. F. Independent No. 2, L. F. Independent No. 3, L. F. Independent No. 4, L. F. Independent No. 5, L. F. Independent No. 9, L. F. Independent No. 9-C, L. F. Independent No. 10, L. F. Independent No. 11, L. F. King No. 9

Jul 1, 1946

By d&apos, D. V. Andrea

Nine rock properties were determined for rocks coming from 49 locations and having a wide range of compressive strengths. Plots of the nine rock properties versus each other were prepared. A stepwise multiple linear regression analysis was performed to obtain several equations for predicting compressive strength. Both linear and curvilinear relationships were assumed between compressive strength and the other rock properties. The prediction equations had multiple correlation coefficients ranging from 0.947 for an equation with 1 variable (point load tensile strength) to 0.986 for an equation with 25 variables. Of the properties tested only point load tensile strength could be used alone to estimate compressive strength with fair accuracy.

Jan 1, 1965

By Alan R. Buehler

The Bureau of Mines conducted a mineral investigation of the 10,500-hectare Cache Peak study area in 1992; the area had been proposed as wilderness. Bureau personnel examined and sampled prospect workings; 14 rock and 20 placer samples were taken during the investigation. The study area is centered about 40 km south-southeast of Burley. Idaho, in the Sawtooth National Forest. There were seven mining claims located inside the study area, and one additional historical mining claim location. Gold, silver, copper, lead, zinc: Possible resource, poor exposure precludes estimate. Marble: Several million tonnes may be suitable for a variety of uses; markets too distant to favor mining. Sand and Gravel: Several million m3, but markets and transportation costs do not favor mining. Quartzite: Several million tonnes may be suitable for metallurgical purposes; however, markets are too limited to mine. Slabs have been quarried at three localities adjacent to the study area, for decorative stone. Production: In 1979, two tonnes of ore were produced and a plan of operations was submitted calling for approximately 5 km of access road for the Last Chance mine. Decorative stone production was not recorded.

Jan 1, 1993

By J. A. Herdlick

At the request of the War Production Board a preliminary examination of the Big Ben molybdenum prospect near Neihart, Cascade County, Mont., was made by the Bureau of Mines under G. N. Bennett, mining engineer, Bureau of Mines Montana district office, in September 1942. Formal investigation, consisting of sampling, core drilling, and metallurgical testing, was later undertaken and completed in 1943. Field work was directed by Robert D. O'Brien, mining engineer, Montana district office, under the supervision of E. W. Newman, supervising engineer, Montana district office. This report describes the deposit, presents the factual data obtained from the sampling and core-drilling operations, and summarizes the results of the metallurgical studies. The deposit was first located and prospected in 1922 by the present owner, Frank Mansikka of Neihart, Mont. Periodic examinations made by responsible mining interests were culminated in 1938 when the Federal Mining & Smelting Co. optioned and investigated the property. No ores have been produced from the deposit to date.

Jan 1, 1949

By C. E. Lapple

To improve mine health and safety conditions, there is need for a portable instrument that mine inspectors can use routinely for rapidly checking concentrations of dust in mine atmospheres. On October 23, 1969, Stanford Research Institute was authorized by the U.S. Bureau of Mines to conduct a study aimed at developing such an instrument under Contract No. H0100186. The results of that study are reported in Technical Report No. 1, "Development of Portable Instrument For Measuring Coal Mine Dust Concentration," August 1970. In that study it was demonstrated on bench-scale that a near-forward optical scattering device gives a linear correlation between mass concentration and optical readout over a range of 2 to 200 mg/m3 with excellent reproducibility. The same correlation was obtained for the Respirable* dust fraction of three different coal dusts within ± 10% and an extreme spread of ± 30%. Based on these results a prototype instrument was designed which was expected to meet all the necessary requirements of a portable instrument for mine use. Because of the excellent results obtained, a further study was authorized by the Bureau of Mines on May 10, 1971 under Contract No. H0111688. The prime objective of this study was to build, calibrate, and deliver to the Bureau of Mines two prototype instruments based on the design previously developed. The emphasis was to be on providing instruments which would meet certain minimum standards of size, weight, response time, sensitivity, ruggedness, reproducibility, permissibility, and cost (ultimate); optimization of the design was to be considered only insofar as it would not significantly delay the development. One instrument was to be delivered after initial calibration of both instruments with Coal Dust PGH. The second instrument was to be used for further calibration with a number of other coal and rock dusts and for assessing other relevant performance characteristics. This report summarizes all the results of this second study.

Jan 1, 1972

By R. E. Moore

Refractories are unique ceramic materials, which are used in large quantities in steel making furnaces, metal smelting vessels, and glass melting tanks. They are required to possess high thermal shock properties and good slag corrosion resistance as well as creep resistance at high temperatures. Therefore, they are made from very refractory minerals such as lime, periclase, corundum, spinel, and zirconia. Slags are vitreous materials produced as a residue in steel refining processes. They cover a wide range of compositions and may contain pure oxides, silicates, and sulfides as well as fluoride phases depending on the melting and smelting processes. These minerals exhibit spectacular cathodoluminescence color under electron bombardment; therefore, cathodoluminescence (CL) microscopy is found to be a superior technique for the characterization of refractory corrosion by slags. Examples included in this study are (1) reaction of fluorine containing mold slags with ZrO2-C nozzle refractories promoting crystallization of the Cuspidine, Ca4Si2O7(F,OH)2, (2) corrosion of fusion cast refractories in TV panel glassmaking furnaces and formation of glass defects, and (3) reaction of spinel based castable refractories with copper smelting slags.

Jan 1, 2001

By Nicolas Reynier

The separation of radionuclide during rare earth element (REE) production is an important requirement for developing the Canadian REE mining industry. Separation of actinides from REE is often a large concern in the rare earth industry because of the need to manage the radioactive nuclides. A patented process developed for actinides extraction from radioactive wastes was applied to REE ore. Objectives were to optimize the process for REE leaching from ore, and separate radioactive impurities from sulphuric and nitric liquor by ion exchange (IX). Ore leaching was optimized using a surface response plan to ensure statistical significance. In optimized conditions, solubilization yields ranged from 90–95% for Th, 60–75% for U, 48–55% for LREE, and 59–75% for HREE in sulphuric and nitric media. Both media were compared for radionuclide removal from rich REE-bearing mineral liquor by IX. Actinides separation ranged from 92–97% for Th and 69–96% for U in sulphuric and nitric media.

By Michael J. Pazuchanics

This report documents the current status of the U.S. Bureau of Mines ongoing investigation of the use of adaptive signal discrimination (ASD) systems to distinguish between cutting coal and cutting rock. Cutting-tool forces and vibrations were measured in the laboratory using both conical bits and roller cutters in a linear-cutting apparatus for several material samples and two cutting directions. A number of ASD systems consisting of one or more signal classifiers were trained and tested to study how data window size, type of signal feature, and combining (polling) of classifier results influence system performance. The results show that ASD system recognition rates can be improved by increasing data window size, removing air-cutting portions from the signal data, overlapping data windows, and combining (fusing) information at various levels of ASD system operation.

Jan 1, 2010