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By H. B. Brunot, L. C. IlsLey

The chief object of the Electrical Section of the United States Bureau of Mines is the study of causes and means of preventing accidents resulting from the use of electricity in mines . A large part of this work for the last 20 years has been the inspection and testing of mining equipment under the provisions of schedules which give the minimum requirements considered essential for the safety of equipment intended for use at or near the working faces of dusty or gassy mines . During the first few years of this work , particular attention was paid to the explosionproof features of the various accessories such as motors , controllers , and other parts . The knowledge of the essentials necessary for safe designs of enclosures has since been augmented by field experience and by data obtained in testing a large number and variety of designs . With our present knowledge it would seem that a disproportionate stress was placed on making the various enclosures explosionproof , but not enough thought was given to the danger from wiring and connections outside of explosionproof enclosures . The list of equipment that has met minimum requirements for safety and has been approved as permissible by the Bureau of Mines includes storage - battery locomotives , power trucks , drills , loading machines , conveyors , cutting machines , room hoists , pumps , concrete mixers , and rock-dusting machines . The wiring on some of the machines is comparatively simple and sometimes , except for the trailing cable , may be entirely within the explosionproof enclosures . In general , there is outside wiring between enclosures , and on the larger machines the wiring may be extensive and complicated . In considering the safety of wiring for mining machinery , attention must be given the severe service and unfavorable surroundings imposed by mining conditions . Some of the matters that require consideration are : ground . The lack of care of the exterior wiring to be expected in the average mine . The lack of adequate periodic inspection of the wiring . The absence of adequate facilities for satisfactory inspection and repairs under- The severe conditions of moisture , dirt , mechanical injury , and low voltage encountered in mining service .

Apr 1, 1931

By A. Saigal

The effect of temperature on the cutting forces during machining of alumina reinforced aluminum composites was investigated, Aluminum 6061, 10% Al2O3 reinforced composite and 20% Al2O3 reinforced composite were tested, A 5/8-inch diameter high-speed steel end mill, a Micro 100 TiN coated single edge endmill cutter and a two-fluted solid carbide insert cutter were used for tooling, The results, in general, showed an increase in the cutting forces as the temperature of the material increased, From the raw data, there are temperatures ranges in which the force data did decrease but they were insignificant with regards to predicting a downward trend. A regression analysis was used to understand which variables had the greatest affect on the forces being generated, The correlation and regression analysis showed that at 600 rpm (velocity: HSS- 98,2 sfpm, Micro 100 cutter - 78,5 sfpm, solid carbide cutter - 192,4 sfpm) the tooling, the workpiece material, built up edge, and temperature were statistically significant factors in the test, Tooling was a significant variable in all testing, The smallest forces recorded during machining were generated with the solid carbide two-fluted endmill cutter, Visually, the solid carbide tooling produced a better surface finish during the testing which made it the tool of choice, In addition, the force data proved that as the cutting speeds were increased, the cutting forces decreased.

Jan 1, 2005

By Horst Konig

This paper illustrates that, with the application of new processes, smaller steel plants using local raw materials can be economical and advisable. It also introduces the problems connected with the direct reduction processes, which use non-coking coal or gas as reducing agents, and which are employed in connection with conventional reduction to produce excellent results. Electric smelting is also discussed, and some practical examples of operating plants are given.

Jan 1, 1970

By E. R. Bauer

In response to the mandates in the MINER Act of 2006, the National Institute for Occupational Safety and Health (NIOSH) conducted refuge alternatives research that included characterizing the utility, practicality and survivability of refuge chambers and outby safe havens. NIOSH also prepared and delivered a report to Congress in late December 2007 that summarized the findings of the re-search, included recommendations concerning the design and performance specifications for refuge alternatives, and focused on specific information that could inform the regulatory process on refuge alternatives. This paper highlights NIOSH?s research and recommendations concerning refuge alternatives, survivability evaluations of refuge chambers and presents a brief review of the current deployment of refuge chambers in underground coal mines in the U.S. The research has lead to the conclusion that refuge alternatives have the potential for saving the lives of mine workers if they are part of a comprehensive escape and rescue plan and if appropriate training is provided.

Jan 1, 2009

By Shakuntala Tudu, Indrajit Paul, Surajit Sinha, Pulibandla Basaveswara Rao, Shaik Mahaboob Basha, Srinivas Dwarapudi

The iron and steel manufacturing sector directly accounts for 7–9% of global CO2 emissions. Raw material preparation, such as iron ore sintering, pelletizing, and cock making, is the major CO2 emitter. As climate change becomes a bigger concern, steel manufacturers need to lower CO2 emissions without hindering efficiency or increasing costs. In recent years, the percentage of iron ore pellets in blast furnaces has increased due to its uniform size, good reducibility, and high tumbler index. Pelletizing is energy-intensive and emits considerable CO2. Around 20% of CO2 emissions during pellet making come from fluxes. In the present work, the authors established a novel CO2- free flux called wollastonite (CaO.SiO2) for sustainable palletization. Pellets with varying percentages of wollastonite (0–6%) are prepared and tested for chemical, physical, and metallurgical properties. Image analysis through an optical microscope is carried out to quantify the phases of fired pellets. SEM–EDS is performed to evaluate the chemical composition of the melt and slag phases. The results showed that the reducibility index (RI) and swelling index (SI) of pellets decreased with an increase in wollastonite dosage. Pellet strength increases with an increase in wollastonite addition up to 1.2% CaO (2.27% wollastonite), and a decrease in strength is observed thereafter. The increase in strength is attributed to the increase in slag bonds. The decrease in strength beyond 1.2% CaO is mainly because of an increase in low melting eutectics and more magnetite content. Pellets with 2.27% wollastonite to get 1.2% CaO showed good physical and metallurgical properties.

Mar 4, 2024

By Edward F. Redente

Several research projects have been conducted in the western United States to determine the optimum soil replacement thickness for reconstruction of rangeland and cropland. However, the information gained from these studies tends to be site-specific and not broadly applicable. Moreover, the possible interaction between soil thickness and mechanical and fertilizer manipulation of the overburden has not been adequately studied. To meet these information needs, research was initiated at Trapper Mine in northwestern Colorado in 1980 to study vegetation response to soil thicknesses of 15,30,45, and 60 cm and five manipulations that included disking, ripping, and fertilizing. All crops were harvested at peak standing crop and then weighed in the laboratory. Wheat grain yields were highest when soil thickness was 45 cm and the soil and overburden were ripped. Alfalfa yields appeared to be highest when overburden was disked and fertilized and soil was replaced to a thickness of 60 cm. For range vegetation, standing crop biomass was highest when overburden was ripped and soil was replaced to 60 cm thick. However, optimum performance was obtained from the maximum number of species and life forms by disking overburden and replacing 15 cm of soil. The performance of most range plant species has improved over the three years of the study. When the results of this study are compared to the results of other soil thickness studies, we can conclude that selection of management practices should be influenced by local climate, local soil and overburden conditions, type of crop or vegetation to be grown, and specific management goals for that crop or vegetation.

Jan 1, 1984

By William Y. Mo

This report presents preliminary results of a study undertaken to investigate quantitative characteristics of the demand for steel mill products and its major end-use components. The major end uses included in the study are the steel mill products used in construction, in automobiles, in producer durables, and in consumer durables. The main objectives of the research underlying this study are as follows: (1) To formulate and estimate the empirical demand relations for steel and the four major end uses in the United States; (2) to measure and calculate the responsiveness of the U.S. per capita steel consumption with respect to the changes of the steel and other nonferrous metals prices; (3) to determine and quantify the relative importance of the underlying demand explanatory factors in contributing to the average year-to-year increases (or decreases) of the U.S. per capita steel consumption; and (4) to adapt and use the estimated demand relations in making projections of the U.S. future demand for steel and the major end-use components. After extensive preliminary investigation, three versions of simple linear demand relations are selected and estimated by means of ordinary least squares (OLS) method. The annual data for the period 1947-65 are used in the estimation. Direct and cross price elasticities of demand are computed for each of major end uses. The relative importance of demand explanatory factors in contributing to the average year-to-year changes of U.S. per capita steel consumption are also calculated. For making projections, a simple autoregressive time trend model is used in estimating the future values of independent variables. Since the estimated demand relations are valid for projections only if the estimated parameters can be assumed to be unchanged in the future, and consequently, the projections derived in the study should be interpreted accordingly.

Jan 1, 1970

By Bengt H. Fellenius

It is a truism that in the design of pile foundations one must consider both capacity and settlement. As to capacity, most basic text books contain simple methods of design of capacity of single pile. More sophisticated methods are the subject of many journal papers. However, methods for design considering settlement of pile foundations are scarce. (Most confuse settlement with the movement due to load-transfer?the transfer of load from the pile to the soil). Furthermore, for both capacity and settlement, most methods include several simplifying assumptions regarding soil layering and neglect the effect of the frequently occurring fill and excavations, as well as changes of the groundwater table and pore pressure distribution. Therefore, the methods may provide qualitative results, but not quantitative. Because of this situation, pile design often appears as somewhat of a guessing game and a very subjective?and risky?occupation. This need not be. Pile foundation design is controlled by three factors: capacity, strength, and settlement requirements and these have been combined in a method called "the unified design of piles and pile groups considering capacity, settlement, and negative skin friction" (Fellenius, 1984; 1989), which method is summarized in this guide.

Jan 1, 1991

By K. J. Gill, P. Chiotti, J. T. Mason

Thermal, metallographic, and vapor pressure data were obtained to establish the pkase boundaries and the standard free energy, enthalpy, and entropy of formation for the compounds in the Y-Zn system. Three coinpounds with stoichiometric formulas of YZn, YZn2, and Y2Zn17 melt congruently at 1105", 1080°, and 890°C, respectively. Four compounds with stoiclziometric formulas of YZn3, YZn4, YZn5, and YZn,, undergo perztectic reactions at 905", 895", 870º, and 685ºC, respectively. Three eutec-tics exisl in this system with the .following eutectic temperatures and zinc contents in wtpct: 875ºC, 23.2 Zn; 1015ºC, 51 Zn; 865ºC, 82 Zn. The YZn, pkase undergoes an allotropic transformation. In the two phase YZn2 -YZn alloys the trans.formation gives a weak thermal arrest at 750°C, whereas in the two phase YZn2-YZn3 alloys no thermal arrest is observed and the transformation occurs over a temperature range below 750°C. At 500°C the free mzergies of formation per lnole vavy from —18,090 for YZn to —53,430 fov YZr11 and corresponding enthalpies vary from -24,050 to -92,080. The free energies and enthalpies per g atom as a function of composition show a maximum for the YZn2 phase; the 500°C values are -9580 and -13,180, vespectively. 1 HE only information found in the literature on Y-Zn alloys was the observation reported by Carlson, Schmidt. and speddingl that Y-20 wt pct Zn forms a low melting alloy. The alloy was produced by the bomb-reduction of YF3 and ZnF2 with calcium in an investigation of methods for producing yttrium metal. The solubility of yttrium in zinc has been determined by P. F. woerner2 and reported by Chiotti, Woerner, and Parry.3 In the temperature range 495" to 685°C the solubility may be represented by the relation In these equations N represents atom fraction of yttrium and T is the temperature in degrees Kelvin. The purpose of the present investigation was to establish the phase diagram for the Y-Zn system and to determine the standard free energy, enthalpy, and entropy of formation for the compounds formed. MATERIALS AND EXPERIMENTAL PROCEDURES The metals used in the preparation of alloys were Bunker Hill slab zinc, 99.99 pct pure, and Ames Laboratory yttrium sponge. Arc-melted yttrium buttons contained the following impurities in parts per million: C-129, N-12, 0-307, Fe-209, Ni-126, Mg-13, Ca < 10, F-105, and Ti < 50. Some of the alloys containing 70 wt pct or more of Zn were prepared from yttrium containing 5000 ppm Ti as a major impurity. Tantalum containers were found to be suitable for all alloys studied and were used throughout the investigation. The pure metals, total weight about 30 g, were sealed in 1 in. diam tantalum crucibles by welding on preformed tantalum covers. A 1/8 in. diam tantalum tube was welded in the base of each crucible for use as a thermocouple well. Welding was done with a heli-arc in a glove box which was initially evacuated and filled with argon. The sealed crucibles were enclosed in stainless steel jackets and heated in an oscillating furnace at temperatures up to 1150°C. Homogeneous liquid alloys were obtained within a half hr at these temperatures except for alloys containing less than 20 pct zinc. The latter alloys were held at 1000º to 1100°C for 2 to 3 days in order to obtain equilibrium. After the initial equilibrations the tantalum crucibles containing the alloys were removed from the steel containers and used directly for differential thermal analyses. Further annealing heat treatments for alloys in which peritectic reactions were involved were carried out in the thermal analyses furnace. After thermal analyses the tantalum crucibles were opened and the alloys sectioned and polished for metallographic examination. In the following discussion alloys referred to as "quenched" were obtained by quenching the sealed stainless steel jacket containing the tantalum crucible and alloy in water. The differential thermal analyses apparatus used was a modified version of the one described in an earlier paper., The graphite crucible was replaced by an inconel crucible, the nickel standard and sampie container were separated by a 1/8 in. MgO plate, no getter was used, and provisions were made to

Jan 1, 1963

By R. P. Bhagat

The paper reports results on sinterability of iron ores from the mines of Tata Steel Limited. The objective was to improve tumbler index (TI) of sinter and its reduction parameters, reduction degradation index (RDI) and reducibility (RI) while maintaining strand productivity same or to improve. Pot sintering experiments were carried out with Joda and Noamundi mines having LOI 3.8% and 2.9% respectively. Sinter basicity (CaO/SiO2) was varied in the 2.1 to 2.5 range and its MgO content was kept in the 1.4% to 1.8% range according to the blast furnace requirement. The ignition condition and vacuum was maintained according to the plant practice. The effect of variables namely, granulometric composition of ores vis-à-vis that of sinter mix, bed height, solid fuel, moisture content of green mix on the sintering indices was studied. The productivity with Noamundi ore (26 %+6.3 mm) was lower than that with Joda ore (45% +6.3 mm) at 4% coke in the mix and sinter basicity (CaO/SiO2) 2.1. However, with 4% coke (ash 22%) the RDI value was significantly high in case of Noamundi Ore, which decreased significantly to 29% with 5% coke. The size parameter of ore fines and its LOI content do influence the sintering speed and the sinter properties significantly. At 2.1 basicity ratio, the sinter with the Joda ore having coarsergranulometry had highest TI (=70.2%). The RDI (27%) in this case was inferior to that (23.2%) when Joda ores with finer size was sintered. Better RDI with finer sized ore could be attributed to better assimilation of CaO/ MgO with more balanced and uniformly distributed hematite minerals. The size parameter has been inter-influenced by the coke requirement. With the lower mean sized Joda ore the sinter RDI decreased significantly to 23% and the productivity improved to 42.9 T/(sq m*d) when the coke in the mix increased from 4% to 5%. An attempt to reduce the coke in the mix from 5% to 4% with respect to both the ores was not successful as it resulted higher RDI and lower strand productivity. The present study has revealed that sinter RDI improves (decreases) with decrease in the sintering time, while such correlation was absent between TI of sinter and speed of sintering. Corollary to this observation, one can take advantage of other stronger parameters to increase the sintering speed (and hence sinter productivity) without affecting the sinter strength. In the present study higher FeO sinters has displayed excellent RDI, however cold strength of sinter was not correlated with its FeO content. The TI and RI parameters of sinter improves marginally with increase in its MgO content while RDI got worsened. Keywords: LOI content, iron ore, reduction properties, sinter, noamundi, joda

Sep 1, 2012

By A. B. Cecala

Enclosed cabs have been used for many years to isolate workers on mobile equipment in the mining industry for health and safety reasons. These enclosed cabs create a microenvironment for workers where they can be either more protected or more vulnerable to contaminants. Over the past decade, the U.S. National Institute for Occupational Safety and Health (NIOSH) has performed substantial research efforts to improve the air quality inside enclosed cabs of underground and surface mobile mining equipment. In these efforts, NIOSH has partnered with mining companies, original equipment manufacturers (OEMs) and manufacturers of filtration and pressurization systems in a synergistic effort to reduce respirable dust and improve the air quality inside these enclosed cabs. Various field studies over this time have shown an array of results ranging from very minor to very significant reductions (protection factor: 3-89) in respirable dust levels inside these enclosed cabs. In addition to and concurrent with the field work, NIOSH also performed a comprehensive laboratory study to evaluate all the factors involved in cab filtration and pressurization systems and identified those factors that were most significant for an effective system. From this comprehensive research effort, the key components for an effective filtration and pressurization system have been identified in an effort to provide the best air quality to equipment operators inside of enclosed cabs of mobile mining equipment, thus minimizing respirable dust exposure.

Jan 1, 2014

By Staff

The Tetreault mine, operated by the British Metal Corporation (Canada), Limited, holds a unique position in Canadian mining, being the only steady producer of zinc in Canada east of the Rocky mountains. Its importance in Canadian zinc production may be gauged with some accuracy, since, in 1927, it was responsible for over 13 per cent of the zinc output of the Dominion. In addition, it also made valuable contributions to the production of lead, silver, and gold. Location: Situated in the foothills of the Laurentian mountains, 600 feet above sea level, 20 miles from the St. Lawrence river, and 52 miles due west from the city of Quebec, the property is in the township of Montauban, county Portneuf, Province of Quebec, as shown in Figure I. The municipality of Montauban, immediately adjoining the mine, has a permanent population of 700 people and is six miles by road from Notre Dame station on the main line of the C.N. Rys. between Montreal and Chicoutimi-Notre Dame being n6 miles by rail from Montreal. Connection by 19 miles of dirt-and-gravel road with the Provincial highways&apos; system of Quebec Province, the city of Quebec, which is distant 78 miles, can be reached by automobile in less than three hours, while the distance to Montreal by road is 16o miles .

Jan 1, 1928

By Renfeng Song, Shaoyan Wang, Zhiqiang Zhang, Ke Guo

Leaching titaniferous magnetite concentrate with alkali solution of high concentration under high temperature and high pressure was utilized to improve the grade of iron in iron concentrate and the grade of TiO2 in titanium tailings. The titaniferous magnetite concentrate in use contained 12.67% TiO2 and 54.01% Fe. The thermodynamics of the possible reactions and the kinetics of leaching process were analyzed. It was found that decomposing FeTiO3 with NaOH aqueous solution could be carried out spontaneously and the reaction rate was mainly controlled by internal diffusion. The effects of water usage, alkali concentration, reaction time, and temperature on the leaching procedure were inspected, and the products were characterized by X-ray diffraction, scanning electron microscope, and energy dispersive spectroscopy, respectively. After NaOH leaching and magnetic separation, the concentrate, with Fe purity of 65.98% and Fe recovery of 82.46%, and the tailings, with TiO2 purity of 32.09% and TiO2 recovery of 80.79%, were obtained, respectively.

Jun 16, 2021

By Bernd Hagenah, Katie Theis, Cristina Lauzon, Petr Pospisil

Lidding over or tunneling existing transportation infrastructure is currently under review in several U.S. cities. The main reasons for this are the use of the created space for urban development, the reduction of noise and exhaust fumes for the residents, and, thus, a significant increase in the quality of life. The main aspects to be considered during the planning process are (1) total investment and operational costs, (2) impact of construction works on current traffic, (3) safety and fire protection, and (4) socio-environmental issues. The paper presents some basic planning principles, and experiences of recent urban highway coverages are shared.

Jun 23, 2024

By A. F. Brock

Introduction During the past ten years, shaft sinking has been going on continuously at Inco and new shafts and shaft extensions have been sunk under a broad diversity of conditions. The Murray mine and the Stobie section of the Frood-Stobie mine have?been opened and a main hoisting and supply shaft has been sunk at each of these mines; No. 2 shaft at Murray was sunk initially from surface to 1,960 feet and is now being extended; No. 7 shaft at Stobie was sunk from surface to 3,105 feet. No. 2 shaft at Garson has been extended from 2,200 feet to 3,200 feet in depth. At Levack, No. 2 shaft is being extended from 1,860 feet to 2,850 feet for ore hoisting from the 2,650 lev el. At Creighton, No. 6 shaft, collared on 52 level, was sunk 1,740 feet to a total depth of 5,563 feet below surface. It is the deepest Inco working. At Creighton, also, No. 7 shaft is being sunk from surface to the 30 level to handle the ore from caving operations. Ail Inco main hoisting and supply shafts sunk during the past twenty years have been vertical rectangular shafts equipped with two cages and two ore skips. The cages are standard and interchangeable for all shafts except Garson No. 2; they are single-deck, 13 ft. 4 in. by 5 ft. 2 in. inside and are designed to carry a maximum material load of 16,000 lb. The man load is 48 men. Skip capacities at the several shafts vary from 8 to 15 tons. Forty-two hundred feet bas been established as the standard vertical lift, and the permanent hoisting equipment at each shaft is designed for eventual hoisting from that depth.

Jan 1, 1950

By David J. Kusler

A gravimetric method for the determination of carbon dioxide, carbon monoxide, hydrogen, methane, and oxygen in blast furnace top gas is described. Nitrogen may be determined directly by volume measurement or by difference. The method is direct, permits continuous as sampling, and provides an averaged analysis over a selected range of sampling intervals from 1/2 to 24 hr or more. Neither expensive equipment nor specialized personnel are required. The method is suitable for routine analysis, and the results compare favorably with those obtained by established methods.

Jan 1, 1963

By John E. Conley

Of the three chemical elements most vitally essential for plant growth the United States, before World War I, had developed ample domestic supplies of but one-phosphorus. During and shortly after the war period, the fixation of nitrogen was greatly expanded in this country, as in many others, insuring a supply adequate for agriculture as well as for munitions. However, in spite of a search for sources of the third element, potassium, which began years before the war, attained almost frantic intensity between 1914 and 1919, and continued for 10 years thereafter, it was not until 1921 that the American Trona Corporation put its Searles Lake operations into continuous production. This company in 1926 became The American Potash & Chemical Co. but has never supplied much more than 15 percent of the potash consumed in the American market. Likewise, though discovered in 1921 in drill cuttings from oil wells, it was not until 1926 that domestic deposits of potassium salts adequate to render the United States independent of foreign sources of supply were proved to occur in the Permian Basin of Texas and New Mexico.

Jan 1, 1944

By M. Michael, A. Felber

"Mining activities, especially underground mining operations, create great demands on utilized haulage means which cover a variety of different horizontal and vertical distances. In the course of the continuous optimization of the haulage process, the application of textile machine elements, in particular synthetic fiber ropes, offers new opportunities. Therefore the current level of knowledge needs to be improved based on extensive analyses. For the estimation of the scope of these analyses, different fields of application and occurring environmental influences which have an impact on synthetic fiber ropes during their use in underground mining have to be evaluated. The Chair Underground Mining Methods of the TU Bergakademie Freiberg works on a scientific project concerning the use of synthetic fiber ropes in underground mining operations. This paper focuses on the potential application of synthetic fiber ropes in haulage systems in underground mining and exposes critical influences as an outcome of the working environment. These first investigations are the basis for the development of an appropriate experimental series. SYNTHETIC FIBER ROPES FOR UNDERGROUND MINING OPERATIONS The main idea is to optimize underground haulage means to develop even more economic systems. The new and lightweight design of single machine elements seems to be the first step to accomplish this goal. An example is the lightweight design of shaft hoisting ropes. The commonly used steel wire ropes are very heavy and are endangered to snap due to their own weight when reaching a distinguishing length. Thus they may not or only conditionally be used for deep mining operations utilizing shaft haulage. Ropes made of high-tech synthetic fibers weigh only an eighth of steel wire ropes while displaying the same tensile strength. This relation is shown in Figure 1, based on the comparison of fiber strength and density. This could offer new opportunities for deep mining operations, which are anticipated by many mining companies. /1/"

Jan 1, 2015

By T. ?kre, O. M. Dotterud, S. Haarberg, J. Thonstad, G. M. Haarberg

An electrowinning pilot plant has been constructed at Falconbridge Nikkelverk A/S, Kristiansand, Norway. The equipment consists of a mixing tank where the electrolyte composition and temperature are controlled, an electrowinning tank equipped with five cathodes and six anodes of commercial size and design and a dechlorination facility. Electrowinning experiments were carried out in this pilot plant using acid cobalt chloride solution from the cobalt tankhouse. Key parameters were varied to obtain an improved understanding of the cobalt electrowinning process, focusing on the detrimental deposition of cobalt oxide on dimensionally stable anodes. The extent of anode scaling was found to be dependent on the electrowinning conditions. Low pH, temperature and cobalt concentration resulted in less scale being formed, however at the expense of cobalt current efficiency and cell voltage, adversely affecting electrowinning production capacity and energy consumption. When operating at high acidity, pH in the anolyte was higher than in the catholyte, which is believed to be due to H+ ions taking part in the current transport across the diaphragm, migrating out of the bags surrounding each anode.

Jan 1, 2005

By Jamal Rostami, Omid Frough, Wei Hu

Characterizing the abrasiveness of soil/rock and the allowable wear of hard-facing products in various conditions is a critical factor in selection of the best material for certain applications related to drilling and excavation in mining and construction industries. The Soil Abrasion Index test machine at Colorado School of Mines (CSM) is one of the recently developed unique systems capable of testing soil/crushed rock abrasion under various conditions, such as dry, wet, and saturated settings. It is also capable of testing the performance of various types of hard-facing materials in a given geo-material. This paper studies the wear properties of different hard-facing materials in various crushed rocks from a surface mining operation in the iron range region of the USA. The hard-facing materials include regular and hardened steels and six different specialized hard facings, based on chromium carbide. The soil/rock include a standard sand and two rock samples from the surface mine. Fourteen abrasion tests were conducted, where the weight loss of each hard-facing material was measured over timespans up to 1 h of testing. The results show the distinct performance differences between the steels with 17 HRC and 43 HRC hardness and the hard-facing products for this application. The results show the possibility to evaluate the abrasiveness of different rocks at a mine or construction site and the performance of various hard facings in similar working conditions. This is a practical solution for selection of the cutting tool or reinforcement of bucket lips and truck beds for comparison of relative wear life between different wear-resistant materials.