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By B. J. Moore

This publication contains 14,242 analyses of gas samples from oil and gas wells and natural gas pipelines in 40 States and 24 foreign countries. These gas samples were collected in the period 1917-85 as part of the Bureau of Mines survey for helium occurrences. The gas analyses contained herein were made by several methods over the period covered. Analytical work on samples collected early in the period was done on the Orsat apparatus. The one-cut apparatus and four-cut fractional distillation equipment were added later. A mass spectrometer was acquired in 1949 and used for all gas analyses made after that time. From 1917 to 1978, helium analyses were made on special helium analytical equipment designed and built by the Bureau of Mines Helium Operations Laboratory. In 1978, this apparatus was replaced in the quantitative helium analysis work by a gas chromatograph.

Jan 1, 1987

By C. F. Wingquist

As part of an ongoing study to determine how the wear of mining tools affects dust generation, the Bureau of Mines has measured bit tempera-ture rise during cutting of abrasive rock. Radial bit wear-flat tem-peratures generated by linear cutting in Berea Sandstone were measured as a function of cutting depth and speed. Depths of cut (DOC) were 1/8, 1/4, and 1/2 in, and cutting speeds were 10, 40, and 80 in/s, respectively. Temperature sensing was accomplished by emplacement of a miniature thermocouple into the center of the wear flat. Temperatures observed ranged from 2000 to 5000 C. Correlation between depth and temperature was weak. Temperature increased linearly with speed at 1/2-in DOC, but data taken at 1/8-and 1/4-in DOC produced inconclusive results. The results indicated that at least for deeper cuts (1/2 in), bit temperature, and therefore wear, can be reduced by lowering the cutting speed.

Jan 1, 1987

By F. Siciliano, D. Bai, S. Yue, A. M. Elwazri

The influence of niobium addition and very low temperature (`cool') deformation on the microstructure and properties of low carbon microalloyed steels was investigated. In this work, the specimens were heated at 1200°C and held at this temperature for 20 minutes. Some specimens were aged at 400°C for times ranging from 10 minutes to 10 hours followed by air-cooling. Others were subjected to deformation at 400°C (`cool deformation') prior to aging. It was observed that the proportion of acicular ferrite was increased as the amount of Nb was increased. It was found that cool deformation increased both yield and tensile strengths significantly compared to that of the aged only specimens.

Jan 1, 2005

By A. J. Dickson, A. M. Starfield

This paper reviews the progress made to date in the development of computer models of heat and moisture transfer from rock surfaces to the ventilating air in deep-level mines. The application of these programs to ventilation planning and design is discussed.

Jan 1, 2014

By J. Lu, J. B. Wiskel, D. G. Ivey, E. Niemi, H. Henein

Simulated TMCP using a Gleeble was undertaken to evaluate the effect of the austenite to ferrite cooling rate, coiling temperatures of either 400°C or 500°C and the magnitude of plastic deformation at the coiling temperature on the hardness of a Grade 483 (X70) steel. For comparable apparent cooling rates and deformation conditions, the hardness of the samples were independent of coiling temperature The application of a minimum compressive deformation > 8% was required to increase hardness at both simulated coiling temperatures of 400°C and 500°C. An increase in hardness was also observed with increased cooling times between 800°C and 500°C (i.e., slower cooling rates).

Jan 1, 2005

By H. Ranjbar

The Darrehzar porphyry Cu deposit is situated in the Urumieh-Dokhtar magmatic suite of Central Iran. The REE and trace element data suggest that the deposit lies within a continental margin setting. Phyllic and propylitic alteration are pervasive in the area but potassic and argillicalteration are not readily recognized on the surface. This is possibly the result of super gene weathering of the surface rocks or because of an intense phyllic overprint. Poor soil development and abundant outcrop make the area suitable for a case study of lithogeochemical exploration technique for Cu deposits. A total of 262 rock samples was collected over the area and analyzed for 15 elements. The geochemical data cor-relate with the mineralogical composition of the rocks with the phyllic zone being marked by high-er concentrations of Si, Al, K, and by a high sericitization index while Ca, Mg, Sr, total Fe and Mn are more abundant in the propylitic zone. The lithogeochemical study indicates a metal zonation from a Cu + Mo-rich core to a Zn + Pb ± Ag-rich outer zone. Principal component analysis is useful for separating element associations, which in turn reflect the alteration halos. Principal components 1 and 2 depict alteration zoning, where-as 3 shows an association of Cu and Mo, that roughly defines the mineralized area.

Jan 1, 1997

By Descarreaux. Jean

"The Abitibi volcanic belt was sampled along a cross section extending from Matagami to a point east of Rouyn. A few samples were also collected in Louvicourt township, Quebec. The major elements were determined for 344 samples, and rock names were defined using normative minerals. The analytical data were studied by means of variation diagrams. The Abitibi volcanic belt is characterized by rocks belonging to both the tholeiitic and calc-alkaline magmatic series, but they show some differences as compared to some typical reference series, particularly those from Japan. Basalt is the predominant rock type and accounts for 44 per cent of the sampled outcrops. The volcanic rocks are relatively poor in K2O and TiO2. Regionally, the volcanogenic copper-zinc mineralization is associated with the calc-alkaline volcanic sequences. Locally, within such sequences, some types of abnormal deviations from the averages are recognized only in association with the copper-zinc mineralization. The anomalies are ascribed to hydrothermal alteration consisting of the introduction of MgO and removal of N a20; enrichment in K20 is also observed where zinc mineralization predominates. Examples of such anomalous zones show that, in places, this alteration phenomenon can be quite extensive. Petrochemical characteristics can be used as geochemical ore guides in exploration programs."

Jan 1, 1973

By S. K. Kawatra, H. J. Haselhuhn

"Thickening is used during two primary mineral processing operations: water removal and desliming. During water removal, the pulp density is increased through the injection of flocculants. These flocs settle and create a dense pulp while clarified water is removed through the overflow. During desliming, fine particles are removed through the overflow. Desliming can also be used as a mineral separation process known as selective flocculation-dispersion, where valuable minerals are flocculated and gangue minerals remain dispersed and exit through the overflow.There are many ways to analyze thickener performance on a laboratory scale, but these analyses often do not correlate well with full-scale performance. Some pilot-scale systems have been designed using a semicontinuous approach, but the amount of material required to perform their tests can make semicontinuous pilot thickeners impractical for most applications. This paper focuses on the design and optimization of a continuous pilot-scale deslime thickener that requires minimal material to operate. The design, optimization strategy, and an example study of reagent selection are demonstrated. IntroductionMany laboratory methods have been employed to size and optimize thickener performance. The most common of these include the Coe and Clevenger method and methods derived from the Kynch theory of sedimentation. The Coe and Clevenger method was developed in 1916 and was proven for slurries that do not require flocculation to settle. This method proposed that the settling rate of the pulp is only a function of the solids concentration. It is executed by creating slurries of several different concentrations of solids and performing bench-scale settling tests in graduated cylinders. For each concentration, a thickener unit area can be determined using the following equation (Coe and Clevenger, 1916; Laros, Slottee and Baczek, 2002):"

Jan 1, 2017

By William G. Pariseau, Mark K. Larson, Douglas R. Tesarik, Heather E. Lawson

"This contribution describes development and application of a user-friendly finite element program, UT3PC, to address three important problems in underground coal mine design: (1) safety of main entries, (2) barrier pillar size needed for entry protection, and (3) safety of bleeder entries during the advance of an adjacent longwall panel. While the finite element method is by far the most popular engineering design tool of the digital age, widespread use by the mining community has been impeded by the relatively high cost of and the need for lengthy specialized training in numerical methods. Implementation of UT3PC overcomes these impediments in three easy steps: First, a material properties file is prepared for the considered site. Next, mesh generation is automatic through an interactive process. A third and last step is simply execution of the program. Examples using data from several western coal mines illustrate the ease of using the application for analysis of main entries, barrier pillars, and bleeder entry safety.INTRODUCTIONRational design of safe underground entries and crosscuts, barrier pillars, and bleeder entries begins with a site-specific analysis of stress. An analysis of stress identifies the critical regions of high-stress concentration where yielding is likely and additional or more focused ground control measures are needed. This analysis also identifies regions where stress concentration is low, and risk mitigation is less urgent. Displacements induced by mining, including roof sag, floor heave, and pillar squeeze, are also of importance to stability. The popular finite element method is well-suited for such analysis and has been in use for studying coal mine engineering problems since the late 1960s (Dahl, 1969). The method has been taught in undergraduate engineering curricula for many years and offers an alternative to existing design procedures based mostly on rules of thumb, empirical methods based on mine data, and predigital-age concepts of strata mechanics. However, despite the versatility of the finite element method, usage has been limited, mainly because of the cost of the software and the required training in numerical methods.The program UT3PC (Pariseau, 2017) has evolved from early two-dimensional versions in the era of mainframe computers. These early versions were still quite limited using only a few hundred elements that required overnight turnaround times. Recent versions of UT3PC are convenient and efficient desktop programs that use several million elements. With the advent of personal computers in the mid-1980s and subsequent increase in computer speed, expanded memory, and lower costs, applications for mining increased in three-way cooperative projects among industry, the former U.S. Bureau of Mines, and academia. The Spokane Research Center of the U.S. Bureau of Mines, in cooperation with the University of Utah, developed a two-dimensional desktop finite element program, UT2PC, available to the mining community in 1991. This was a short course offered at the 1991 SME Annual Meeting in Denver, CO."

Jan 1, 2017

By R R. J McAllister, K Moffat, S Heyenga

This paper examines the statistical relationship between quality of life indicators and the gross value of mineral production from Australian regions. We used quality of life indicators, aggregated for 673 local government areas, of household income, housing affordability, access to communication services, educational attainment, life expectancy and unemployment. We find no evidence of systematic negative associations between quality of life and the gross value of minerals production. Instead, mining activity has a positive impact on incomes, housing affordability and communication access across regional and remote Australia. Whilst we do not establish causality between mining activity and quality of life, our analysis prompts a rethink of the æresource curseÆ as it applies within a single country. Nevertheless, our findings are tempered by extensive anecdotal and empirical evidence of the negative social impacts of mining on specific demographic sectors, localities, families of fly-in, fly-out mining operations and individuals. This contrast may be a scale issue, with the regional benefits of mineral wealth masking highly-localised inequalities and disadvantage. We suggest that there is a need to better understand these impacts and, more importantly, the types of policy mechanisms government and industry can adopt to mitigate or avoid them.

Jan 1, 2009

By Drummond Earley III

The hydrology of in situ leach mining operations is being studied by the U.S. Bureau of Mines using a variety of techniques, and the Bureau has made significant advances in tracking and modeling the flow of leach solutions in rock formations. However, the influence that leach solution composition has on the hydrology of these systems is poorly understood, and geochemically-controlled changes in the hydrologic characteristic of ore deposits during in situ leach mining of porphyry-hosted, copper oxide ores have not been previously studied. The Cyprus Casa Grande in situ leach mining operation mines fracture-hosted and disseminated copper oxides (predominantly chrysocolla) hosted by granodiorite porphyry using a pattern of underground wells. The injection solution consists of sulfuric acid raffinate from a solvent extraction-electrowinning plant. Chemical analysis of representative injection and recovery solutions reveals that gangue cation concentrations in these solutions are high, and geochemical modeling shows that the solutions are saturated or nearly saturated with respect to gypsum, jarosite, and various amorphous oxides. Precipitation of these solids is evoked by calcium-exchange reactions, rising pH, and perhaps locally rising redox potential, as the leach solution reacts with the ore minerals, host rocks, and the atmosphere. Mass and volume balance calculations show that approximately 25 cm of precipitates are formed per gram of copper recovered at Cyprus Casa Grande. The results of geochemical modeling agree with petrologic examination of pre-and post-leach core samples from the leached horizon. Moreover, hydrochemical modeling and hydrologic field data suggests that chemical precipitation causes significant decreases in porosity and permeability during in situ leach mining of porphyry-hosted, copper oxide ore.

Jan 1, 1992

By H. Qi, J. L. Feng, D. J. Li

"In the present paper, the characteristics of the granite burst under loading/unloading conditions was studied by means of both laboratory experiment and finite-discrete element method (FDEM). After gaining the mechanical properties of the granite samples under uniaxial compression conditions, the parameters taken as input arguments in the FDEM modelling were then carefully calibrated so as to provide some basic data including Young’s modulus, Poisson’s ratio, uniaxial strength, Lame constants, cohesive strength, and frictional angle for further being used in simulating granite bursts. All the simulating results by the FDEM were basically in agreement with that obtained from the uniaxial compression test and triaxial granite bursts in laboratory, respectively. This study shows that that such computational mechanics of discontinua can be employed to gain powerful insight into the failure mechanism of granite burst, which could also be a useful tool to clarify the collapse mechanism of rock structures in rock engineering design and rock test scheme optimisation. INTRODUCTIONBased on discontinuum state a priori, discontinuous modeling techniques that are commonly referred to as discrete element methods (DEM) treat the material directly as an assembly of separate blocks or particles, which was originally proposed by Cundall (1971) and Cundall and Strack (1979) from the viewpoint of analogous molecular dynamics simulation to better account for and understand the interaction between the blocks. The distinct feature of these formulations is that a constantly changing problem of geometry and contact conditions can be addressed by solving the equations of motion using an explicit time marching scheme (most often in a ‘leap-frog’ format), while updating contact force histories as a consequence of contacts between different discrete elements and/or resulting from contacts with model boundaries (Bicanic 1998). The most notable implementations of DEMs are arguably represented by the universal distinct element code (UDEC) (Itasca Consulting Group Inc., 2013) and the particle flow code (PFC) (Itasca Consulting Group Inc., 2012). Another formulation is the discrete crack framework that is based upon some criteria for an advancement of crack front, which is coupled with extensive local and global re-meshing while simulating by numerical methods such as finite element technique, commonly using fracture theories. Certainly, it is relatively easy to trace the propagation of single crack front governed by some principles of energy release rates (Ingraffea 1997) but tracing of multiple cracks leads to topological and algorithmic complexities. Otherwise, there is no consideration of interacting cracks in these formulations of finite element or enhanced finite element techniques (e.g., in XFEM and ABAQUS)."

Jan 1, 2015

By R. Marleau, R. Assad, J. Dugas

"A study of the geological features of known occurrences of mineralization in Gaspe is the basis for a classification. Nickel, chromite, asbestos and some copper are pre-or syn-Taconic, whereas the most important deposits are tied to granitic post-Taconic stocks. Most occurrences are clearly related to igneous rocks: nickel, chromium and asbestos to Ordovician serpentinite; copper to volcanic rocks of different ages; and copper, zinc and lead to acidic intrusions with apparent zoning. Some lead-zinc deposits lying between the Grande Greve and York Lake formations are stratigraphically controlled. Some occurrences are tied to faults; e.g., the nickel-copper mineralization along the North Grand Pabos fault. Northerly-trending transverse structures appear to coincide with the Gaspe Copper, Mount McGerrigle (Tabletop) granite and Lemieux dome areas of mineralization. JEAN DUGAS, after graduating"

Jan 1, 1969

By M Chen, Q D. Gao, Y G. Hu, P Yan, W B. Lu

The safety and stability of construction structures are often affected by blast-induced waves. Investigating the generation mechanism of shear wave (S-wave) during blasting is important, because it has a strong effect in blasting damage. In this paper the generation mechanism and verification of S-wave was studied analytically and numerically. Under the finite velocity of detonation (VOD) of cylindrical charge or the compression wave (P-wave) communicating with the interface of different media during the propagation, the generation mechanism of S-wave was analysed. Propagation of blasting wave in cylindrical charge was simulated with the elastic model, and the generation of S-wave induced by finite VOD was proved. To compare with different numerical methods in simulating the generation of S-wave, the blasting process of instantaneous detonation was simulated by using the elastic model, elastic-plastic model and smoothed particle hydrodynamics and finite element method (SPH-FEM) coupled model. Results demonstrate that the S-wave could not be found in middle section of the charge if the elastic model is employed. But when using elastic-plastic model and SPH-FEM coupled model, the generation of S-wave could be verified. Under the SPH-FEM condition, the amplitude of S-wave is larger and the arrival time difference between P-wave and S-wave is closer to theoretical results.CITATION:Gao, Q D, Lu, W B, Hu, Y G, Chen, M and Yan, P, 2015. Comparison of the generation of shear wave with different simulation approaches, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 79–88 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By Songgen He, Jianchun Guo

With the development of complex, unconventional and deep reservoirs, it shows that many rocks behave plastically with the influence of clay and confining pressure. Traditional linear elastic hydraulic fracturing initiation models are not good predictors for elastic-plastic reservoirs. With the deformation theory of plasticity, a power hardening constitutive equation was developed in piecewise approximation method. Based on the nonlinear constitutive equation, a model of the stress field around the wellbore was developed considering fracturing fluid penetrating effect and in-situ stress anisotropy. At last, coupled with the maximum tensile strength criterion and Mohr-Coulomb criterion, a new elastic-plastic hydraulic fracturing initiation model was built. The following conclusions were summarized in the paper: (1)The piecewise power hardening constitutive equation based on the deformation theory of plasticity can accurately describe the nonlinearity of elastic-plastic deformation. (2)Whether the rock is yielded or not is determined by in-situ stress, yield stress, Biot coefficient and pore pressure. (3)Plastic yield has little influence on radial stress but significant impact on circumferential stress. The radius of the plastic zone is positively correlated with in-situ stress but negatively correlated with yield stress, power hardening index, pore pressure and Biot coefficient. (4)Initiation modes include tensile failure and shear failure when rock is yielded. (5) For elastic-plastic reservoir, the initiation pressure predicted by linear elastic model is much lower if the rock is yielded.

Jan 1, 2015

By Norman K. Olson

A geologic investigation of mineral resources in South Carolina first began in 1825 when the General Assembly authorized Lardner Vanuxen to conduct a "Geological and Mineralogical Survey of South Carolina." Vanuxen, South Carolina's first State Geologist, reported in 1826 on the limestones (marble) of the Piedmont which during those early years, were burned in many shall, scattered kilns in the region wherever suitable raw material was available. He also mentioned the possibility of using marl from the Atlantic Coastal Plain province for direct application and enrichment to the soil. Since before the year 1844 industrial minerals in South Carolina have been commercially produced literally from A to Z, asbestos to zircon. The first pub¬lished reports of actual commercial production, not just an occurrence, are referenced in Table 1 for 33 known industrial minerals and rocks in South Carolina. Known or suspected occurrences of undeveloped non-metallic mineral resources in South Carolina await future verification by geologic mapping, sampling (including coring), possible beneficiation, and market analysis. These industrial minerals and rocks include, but are not limited to, special, clay minerals (e.g. bentonitic clays, zeolites and others), sillimanite, argillite (lightweight aggregate), kaolin (alumina) and marl (underground storage and tunneling medium). In addition other non-metallic minerals, once mined but still worthy of reconsideration, include topaz (industrial), heavy minerals, barite, feldspar, and monazite. Finally, possibilities for new reserves, as an expansion of existing mine output, might develop for fuller's earth, limestone (lime), sericite (finely divided mica), vermiculite, kaolin (paper coating and filling, other filler), and metallurgical gravel. Official South Carolina data from the U. S. Bureau of Mines for 1974 indicated a total value of mineral production of $105.2 million. During 1974 production consisted of cam-on clays, (brick and tile), fuller's earth, kaolin and vermiculite

Jan 1, 1977

By Michael G. Mayer

Since its invention in 1859 various designs of lead batteries have evolved to meet commercial needs for traction applications and standby power. In recent years major developments have taken place in lead alloys and the chemistry and mechanical design of industrial lead batteries. These are reviewed in relation to their commercial application together with the new type of maintenance free gas re-combination lead-acid batteries which are opening so many new markets for lead.

Jan 1, 1990

By Michael M. Hamilton

In 1985, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied a 37,542-acre portion of the 57,002-acre Riordan?s Well Wilderness Study Area (NV-040-166) in order to evaluate its mineral resources. The area studied is located in Nye County, NV, about 60 miles southwest of Ely, NV. Subeconomic mineral resources of limestone and sand and gravel were identified in the study area. The Troy and Irwin mining districts, 4 miles to the west, were active between 1868 and 1963, producing small amounts of gold, silver, lead, and tungsten from mines well outside the study area. Except for minor prospecting activity, most mining activity in the study area has been since 1980, consisting of claim locations and geochemical surveys.

Jan 1, 1987

By D. Lauriski, E. D. Thimons, A. C. Smith, D. C. Fredley

The National Institute for Occupational Safety and Health (NIOSH) and Northwest Barricade LLC (NWB) conducted a study to evaluate the effectiveness of a novel fire blocking gel for use in underground coal mines to extinguish or retard the growth of a coal fire. The gel agent was subjected to controlled laboratory testing to assess its ability to delay coal ignition. It was then evaluated to determine if manual fire hose application could be used to apply the agent to mine roofs and ribs to provide a safe egress for mine rescue teams from a fire area. The gel agent was also evaluated in a water sprinkler system to determine its potential for use in conveyor belt fire suppression systems. The agent was then tested in live-fire exercises to examine its effectiveness in retarding and extinguishing a deep-seated coal fire and wood fire. Lastly, the ability of a mine rescue team to quickly and safely apply the gel agent to a mine entry during a simulated mine fire exercise was determined.

Jan 1, 2011

By G R. F Alvear Flores

Mineral resources are becoming more complex in composition and structure making it more difficult to produce clean concentrates for primary metal smelting. In parallel, providing technological solutions to the recycling and recovery of end-of-life materials is becoming more important in moving towards the goal of increasing circularity. The availability of fundamental thermodynamic data and advanced thermodynamic tools greatly assists in evaluating these complexities and their impact on existing and new processes. In addition, it is fundamental to support the economic performance of smelters. This paper describes several examples on how fundamental work can be applied to industrial processing..

Jun 17, 2024