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By A. J. Barry

[This is the third report related to fundamental retail roof-bolting research in underground mines (1, 2)3/ and describes an investigation of the torque-load relationship for 3/ -inch, expansion-type mine roof bolts. In a previous investigation the relationship between torque and bolt load was established for 1-inch slotted-type bolts (1). The two types of bolts differ in diameter and method of tightening and consequently may exhibit different torque-load behavior. The 1-inch bolt is tightened by turning the nut, the 3/4-inch bolt by rotating the beaded bolt itself. Experience indicates that roof bolts should be tightened to moors satisfactory anchorage sand to minimise nag of tie roof over the mine opening. The generally accepted means for determining the bolt load is to see a torque wrench to measure he torque applied in tightening the bolt and, from a predetermined relationship between torque and molt load, to, determine the corresponding bolt load. Because frictional effects may vary between one type of shell assembly or bolt and others, 7 types of expansion shell units and 3 types of 3/4-inch-diameter, mild steel bolts were tested.]

Jan 1, 1954

By Luis Martín Tejeda

La simulación numérica es considerada como uno de los mejores métodos de modelamiento y planeamiento en la evaluación de la estabilidad de los taludes en minería superficial. En ese sentido, el presente texto señala que a través del método de tensión-deformación, implementado en programas computacionales basados en el método numérico de elementos finitos, se puede llegar a localizar la probable superficie de ruptura. Asimismo, con los diferentes modelos constitutivos como el elástico perfectamente plástico, estos taludes pueden ser evaluados. Por último, se describe brevemente los mecanismos de ruptura en taludes altos, el cálculo del FS y algunas características del programa de elementos finitos PLAXIS v. 7.2.

Sep 19, 2006

By J. E. Dutrizac

The behaviour of the lanthanide elements during the precipitation of sodium and potassium jarosites at 98oC from sulphate media was systematically investigated. The lower atomic weight lanthanide elements (La to Gd) are characterized by the limited solubility of their alkali-lanthanide sulphates, such as NaNd(SO4)2?H2O, which commonly contaminate the jarosite precipitates. Hence, single phase jarosite-type compounds were precipitated only from solutions containing <0.4 g/L of the La to Sm lanthanides. The sulphates of the heavier atomic weight lanthanide elements (Tb to Lu) have significantly higher solubilities such that solutions containing up to 10 g/L of the individual lanthanides could be investigated without the precipitation of alkali-lanthanide sulphate species. Even at the highest lanthanide concentrations, however, none of the jarosite precipitates incorporated more than 0.3 wt% of any of the lanthanide elements. Comparable levels of lanthanide incorporation were noted in both Na-jarosite and K-jarosite. Although the mass of the jarosite precipitate increased with increasing ferric sulphate concentration or with increasing pH, the extent of lanthanide incorporation was not significantly affected. Clearly, the trivalent lanthanide elements do not substitute extensively for trivalent iron in the jarosite structure. This behaviour likely reflects the significantly lower hydrolyzability and larger size of the trivalent lanthanide ions relative to ferric ions.

Jan 1, 2003

By C. Pin, J. Bruce Wagner

In order to demonstrate the role of defect chemistry in the solid state to a process-metallurgy reaction, laboratory experiments were carried aut to remove copper from liquid lead using lead sulfide which had been doped to provide definite concentrations of cation vacancies. The removal of copper decreases in the order: bismuth- or antimony-doped PbS, undoped PbS or tin-doped PbS, and silver-doped PbS. The data are explained using the simple mass -action law and in terms of the exceedingly rapid interstitial diffusion of coppw in PbS to vacant cation sites. Results are in agree-ment with thermodynamic predictions and certain industrial practices that copper may be removed from lead below the limit of its coexistence with pure Cu,S and pure PbS. The role of defects in solids has been exploited in semiconductors and many device applications, in explaining tarnish formation, dissolution rates, and mechanical properties. The application of these principles to many process-metallurgical problems has not received as much attention. It was the purpose of this study to illustrate the role of defect structures of solids in a process-metallurgical application. When lead is refined, the ore, galena (PbS), is reduced by a series of operations to liquid lead (lead bullion) containing impurities such as copper, bismuth, antimony, arsenic, and silver depending on the original composition, the fluxes added, and the particular type of operation, see Fig. 1. In order to produce a pure lead, a series of refining operations are carried out. A typical lead-bullion analysis before drossing is shown in Table I. Copper is removed first as its presence increases the zinc consumption during the desilverizing process. For preliminary copper removal the lead bullion is brought to a temperature of 440°C in a kettle of 60 metric tons capacity. Some tar (or sawdust or resins) is usually added and the kettle is cooled slowly to 400°C while the liquid is stirred. A solid phase, called a dross, floats on top of the liquid and the particles of the solid phase adhere to the tar. This "hot dross" is collected. It contains mostly lead and copper which are partly oxidized and/or sulfurized if the lead bullion contains some sulfur.*

Jan 1, 1963

By Meliton M. Garcia, Satya Harpalani

The volume of gases produced in major and trace amounts as a result of detonation of explosives in an underground mine was determined. The volumes of major gases (CO, CO2, NO and N02) were measured immediately following detonation, during the mucking operation, and following the removal of muck. Tests to identify and quantify the gases produced in trace amounts were performed following the detonation only. The composition of the gases produced varied significantly depending on the composition of the explosive/blasting agent. An average of 95% of the gases produced were found in the test chamber immediately following the detonation, while 2% was found in the chamber following the removal of the muck. Several compounds were identified in trace amounts. Of particular interest was the detection of benzene, toluene, butenes, ethyl benzene and naphthalene since exposure to some of these compounds, even in trace amounts, could present a serious health hazard.

Jan 1, 1987

By B Whiteley, B Gee

The Northside Storage Tunnel is a TBM driven rock tunnel system designed to collect and store sewage from four major storm overflow points along the existing Northern Suburbs Ocean Outfall Sewer. At present, sewage overflows during wet weather are the main source of pollution for Sydney Harbour. The tunnel system comprises a 16 km long by 3.8 m to 6.5 m diameter tunnel from Lane Cove to the North Head Sewage Treatment Plant and a 4 km long by 6.3 m diameter branch tunnel from West Chatswood. The tunnel will have a typical rock cover of about 50 m to 150 m. Most of the tunnel alignment is contained within the Hawkesbury Sandstone Formation which is generally an excellent tunnelling stratum, and offers few geotechnical constraints. However, the tunnel is required to pass beneath incised palaeochannels at Middle Harbour and Manly with each palaeochannel containing about 70 m of sediment.Innovative geotechnical and geophysical investigations were undertaken to examine the tunnel route and characterise the rock beneath the palaeochannels. These investigations have located zones of poor quality rock beneath one palaeochannel in particular, suggesting significant stress relief had taken place in the rock at times of lower sealevel producing structural features indicative of valley bulging. This paper presents the geotechnical model developed for the tunnel, and the models and constraints for tunnelling beneath the palaeochannels.

Jan 1, 1999

By Gordon T. Clark, Stephen H. Gleaton

This paper discusses the conceptual design of cut-and-cover tunnels currently being considered as one of the replacement options for the earthquake damaged, elevated double-deck highway and seawall built in downtown Seattle 50 years ago. The 4.8 km (3 mile) long, 6-lane improvement consists of 1.6 km (1 mile) of at-grade roadway with aerial interchanges, 1.6 km (1 mile) of large two-level cut-and-cover tunnels along the Elliott Bay waterfront, and retrofit of the 50-year old, 1.6 km (1 mile)long Battery Street tunnel and north transition to grade. Construction of deep cut-and-cover tunnels, in complex glacial geology overlain by hydraulically placed fill immediately adjacent the existing sea wall, will require extensive use of concrete diaphragm walls, ground improvement and dewatering. The potential liquefaction and lateral spreading of the fill materials in this active seismic region pose significant design challenges and risk.

Jan 1, 2003

By Steven T. Mitchell

INTRODUCTION Mill production from the Homestake Mine in 1979 amounted to 1.29 Mt (1.43 million st) of ore containing 5.9 g/t of gold (0.172 oz per st) compared with 1978 production of 1.44 Mt (1.59 million st) containing 6.2 g/t of gold (0.180 oz per st). The average cost per ounce of gold produced in 1979 rose to approximately $250 contrasted with $176 in 1978. This increase in unit cost is the result of inflation, a diminishing ore grade, and productivity losses related to a shortage of experienced miners as well as compliance with federal regulatory requirements. Together, these factors prompted the investigation of several large-scale, highly mechanized underground mining methods. This analysis indicated Vertical Crater Retreat mining to be one of the safest underground methods known today, yet competitive with all other forms of stoping in terms of cost and productivity. Therefore, the feasibility of applying the VCR stoping method at the Homestake Mine was explored. Vertical Crater Retreat stoping is a recent innovation in large- scale underground mining based on C. W. Livingston&apos;s crater blasting theories. Figure 1 illustrates the method which consists of drilling 165.1-mm-diameter (6.5-in.) holes from a topsill down-dip to an under- cut on the level below. The bottom of each hole is then loaded from above with a predetermined charge weight and horizontal slices up to 4.27 m (14 ft) in thickness are blasted into the undercut. Broken ore is extracted from drawpoints located on or below the undercut level.

Jan 1, 1983

By Eugene Frey

"INTRODUCTION The ti taniferous-iron deposits in the Iron Mountain area of the Laramie Range, and particularly the Shanton deposit, were examined by several engineers. 3/ of the Bureau of Mines during 1942, 1943, and 1944. A dip-needle survey also was made early in 1945. 4/ Interest in this property has increased as a result of the exploratory work completed by the Bureau in 1944 on the Iron Mountain deposit, 6 miles northeast of the Shanton property.ACKNOWLEDGEMENTSIn its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief analyzes samples and performs beneficiation tests. Both these branches are under the supervision of Dr. R. S. Dean, assistant director.Special acknowledgment is due to Paul T. Allsman, chief, Salt Lake City Division, Mining Branch; James A. Marsh, district engineer; Paul E. Pesonen, Frank L. Wideman, and Frank H. Gunnell, Bureau of Mines engineers; and to S. R. Zimmerley, chief, Salt Lake City Division, Metallurgical Branch, for analyses of samples."

Aug 1, 1946

By Ernest L. Ohle

Since the first recorded discovery of lead in southeast Missouri near Fredericktown about 1720, knowledge of the deposits has advanced in spurts as a result of outlying discoveries: 1864 Bonne Terre 1890 Flat River, Desloge, Leadwood 1948 Indian Creek 1955 Viburnum The original discoveries at Bonne Terre consisted of residual galena in clay, similar to that in the previous finds at Fredericktown. Occurrences in solid dolomite were not noted until mining of the clay pits exposed the walls of the weathered depressions. The St. Joseph Lead Co. had been established to conduct the operations and it was J. Wyman Jones, first president of St. Joe, who at that time brought about the first of the technological advances that were to occur in the district. He proposed use of the newly invented diamond drill to explore the bedrock showings, after observing the machines in the Vermont Marble Belt.

Jan 1, 1991

By R. N. Lambert

This chapter discusses the evolution of high-speed shaft sinking in the South African goldfields. Whether we are talking of an additional shaft at an existing mine or the opening of a new mine, the increasing depth of the ore-bearing reef and the unremitting inflation of costs have provided the compelling incentive to shorten the time taken to sink a shaft and start earning revenue. The high costs of sinking a modern shaft system in South Africa are indicated by the recent example of a deep-level mine in the Orange Free State where the cost was nearly $22!42 million. This was for a single large shaft of 33 ft 6 in. diam (in all cases, shaft diameters refer to the finished diameter of the shaft, e.g., inside the concrete) and 7600 ft deep with a prestressed concrete brattice wall dividing the shaft into upcast and downcast compartments. Higher costs and the consequent demand for increased tonnages, deeper shafts with higher rock temperatures, which necessitate highly sophisticaled ventilation and refrigeration requirements, have all accentuated the importance of time in a shaft-sinking operation. Rectangular shafts with their simple design and comparatively reasonable sinking speeds remained popular for many years until greater mining depths combined with a host of the other allied problems inevitably led to changes in shaft design. Circular shafts appeared to offer many advantages, particularly when considering ventilation, strength, mechanization, and sinking through bad ground and heavily watered zones. However, these advantages were largely offset by the slow rate of advance necessitated by the need to stop sinking in order to line the shaft. The development of the curb ring which enabled lining to take place above the bottom of the shaft and the use of multideck stages allowing sinking and lining to be carried out concurrently resulted in a major break- through. Rectangular shafts, which are still popular elsewhere, have been superseded in South Africa by circular shafts which are almost without exception the only shafts sunk in our goldfields today.

Jan 1, 1970

By T. A. Rickard

The lodes of Cripple Creek, Colo., partake of the composition of the geological formation which they traverse. The prevailing rocks are andesitic breccia, lying upon granite, and also bodies of phonolite, trachytic phonolite, nepheline-basalt, etc., penetrating both the granite and the breccia. At Kalgoorlie, in West Australia, the prevailing rock is schistose, and has not been certainly identified, though microscopic sections indicate the probability that it was originally an acid eruptive. The lodes are essentially bands, more highly schistose than the encasing rock, and impregnated to a notable degree with disseminated pyrites and secondary calcite. During 1899 Cripple Creek produced 425,590 tons of ore, having a gross value of $15,658,254; during the same period the output of Kalgoorlie was 467,048 tons, valued at $17,724,587. In chemical composition, the ores at Cripple Creek and Kalgoorlie, respectively, present differences equally interesting to the petrographer and the metallurgist. In both cases we have to deal with altered eruptives as the matrix of the ore; but the much older rock of Kalgoorlie has undergone more decompo-

Jan 1, 1901

By Takao Kobayashi

Micro-crack formation zones developed near a crack tip in rocks and ceramics play a significant role in fracture behavior of these materials. In order to study micro- crack formation near a crack tip and its effects on crack behavior, a mica-epoxy composite material was developed. Multi-layer mica flakes were embedded in an epoxy matrix. Under high stress in the vicinity of a crack tip the mica delaminated, simulating the micro-cracking along grain boundaries or crystal planes in rocks and ceramics. A compact tension specimen was fabricated from mica-epoxy composite material. During the test the load and crack opening displacement were measured following the ASTM E561 (R-curve determination) procedure. Through the compliance calibration method the effective crack length and the KR were computed. The experiment clearly demonstrates the formation of micro-cracks and their effects on the overall behavior of the specimen. The paper discusses the significance of micro-crack formation on fracture toughness characterizations, and the advantages of the use of mica-epoxy composite for detailed studies of interaction between the micro-crack formation zone and the specimen geometry and size.

Jan 1, 1982

By L. C. S. Dharmasiri, S. M. Shin, A. Senaputra, J. S. Sohn, K. H. Park, J. Avraamides

Reducing agents can be applied to leach metal values from natural and secondary resources such as laterite ores and deep sea manganese nodules and recycled materials such as spent batteries / catalysts which contain high-valent metal oxides of manganese, cobalt and iron. Selective leaching of some metals can be achieved by selecting conditions to control the saturated solubility and dissolution rates of metals from oxides or mixed metal/oxide matrices. The leaching results are rationalized on the basis of chemical species, Eh-pH diagrams and heterogeneous kinetic models. The role of reducing agents such as hydrogen peroxide, sulfur dioxide and iron(II) sulphate, in acid, alkali and in the presence of complexing ligands such as ammonia for the improvement of the leaching of metal oxides and metals is discussed. Previous studies on acid leaching of metals from nickel laterites, manganese nodules and spent catalysts/batteries in the absence or presence of reducing agents show that the rate controlling step involves the diffusion of protons through a thickening product layer on the particle being leached. It is shown that the leaching of nickel and cobalt from manganese nodules and zinc-carbon batteries in ammoniacal sulphur dioxide solutions also obey shrinking core kinetics.

Jan 1, 2014

By J. C. Fox, V. L. Ketellapper

The Summitville Mine, located in the mountains of Southwest Colorado, is an abandoned gold mine. From 1984 to 1992, Summitville was mined for gold using an open pit heap leaching technology. During this period, the volume of acid mine drainage released from the mine significantly increased. This was attributed to the development of the mine pits, the waste rock piles, the heap leach pad, and increased discharges from the drainage adit. The release of this acid mine drainage resulted in the destruction of the aquatic ecosystem for more than twenty miles downstream of the mine. Beginning in 1993, plans were implemented to reduce the amount of acid mine drainage released from the mine. The majority of this work has been completed at the mine. This work includes removal of the Cropsy Waste Pile, closure of the Heap Leach Pad, and revegetation of disturbed areas. Significant improvements to water quality downstream of the mine have occurred resulting from mine reclamation. Aquatic life has returned to portions of the previously mining impacted areas. This study discusses the actions taken to reduce the amount of acid mine drainage generated at the Summitville Mine, the costs of these actions and the resulting reduction in metal loadings. Over 250 samples taken at over 10 locations since 1993 form the basis of this evaluation. Copper loading is analyzed as an indicator of the effectiveness of the actions taken.

Jan 1, 2002

By C. Hanford Henderson

The belt of copper-bearing rocks of the South Mountain has attracted Attention principally iii the townships of Hamilton Ban and Liberty in Adams County, Pennsylvania, and in the southeastern portion of Franklin County. As the developments, thus far, have been almost exclusively limited to that area, the examination here described extended only within those boundaries. The region, being one of considerable interest geologically, has been the subject of careful study and description, both on the part

Jan 1, 1884

By R. Stefanko, Y. J. Wang, H. R. Hardy, R. Y. Kim

Since 1964, the Dept. of Mining at The Pennsylvania State University has been carrying out extensive studies associated with the phenomena of microseismic activity and inelastic behavior in geologic materials. Briefly, the program to date has involved the following stages 1) Study of the microseismic noise and energy rates for selected geologic materials under incremental, uniaxial tension.1,2 2) Investigation of the frequency spectra of microseismic activity of selected geologic materials under incremental, uniaxial tension.3,4 3) Investigation of the time-dependent inelastic deformation of geologic materials and the analysis of such deformation in terms of mechanical models.5, 6 4) Simultaneous study of microseismic activity and time-dependent inelastic deformation in geologic materials under incremental, uniaxial compression.7,8 Details of the research involved in stage 4 of the program constitute the subject of this chapter. It should be noted that the majority of the experimental data quoted in this chapter forms part of a thesis to be presented by one of the authors (Kim) in partial fulfillment of the requirements for the Ph.D. degree in mining engineering at The Pennsylvania State University. During the last two or three years, a number of important papers have been published which deal primarily with the fundamental structure and mechanical behavior of geologic materials. Recent papers 9,10 have provided research workers in the rock mechanics field with a meaningful overall picture of rock as a structural material. The concept that many

Jan 1, 1970

By J. M. Boutwell

PAGE I. Introduction,.......541 II. General Geography,......542 III. General Geology,......544 1. Sedimentary Rocks,..... 544 2. Igneous Rocks,...... 545 3. Areal Geology,.......546 4. Structural Geology......547 IV. General Character of Ore-Deposits,...548 V. Genesis of the Disseminated Ore in Monzonite,.... 549 1. General,........549 2. Character and Occurrence,... 649 3. Genesis,....... 550 4. Superficial Alteration.....553 5. Conclusion......553 VI. Genesis of the Ore in Fissures,...553 1. Character........... 553 2 Occurrence......554 3. Deposition...... 556 4. Transporting Agent....555 6. Immediate Causes of Deposition..556 6. Superficial Alteration....564 7. Conclusionl ..... 565 VII. Genesis of the Copper-Ore in Limestone...... 566 1. Character......566 2. Occurrencel .....566 3. Deposition......567 4. Relation of Fissures.....569 5. Relation of Intrusives,...571 6. Superficial Alteration....575 7. Conclusion......578 VIII. Periods of Ore-Deposition....578 IX. Dates of Mineralization.....579 X. General Conclusions.....580 I. Introduction. The object of this paper is to present a concise statement on the genesis of the copper- and lead-deposits of the Bingham

Jan 1, 1906

By Paul Stothart

Context ? Industry is active in urban, rural, and remote regions ? Faces a range of environmental challenges and ?social license? issues ? There are also Aboriginal and northern issues ? Also very active internationally, with associated challenges ? Environmental/social groups often target the industry ? The important contribution of the industry should not be overlooked Useful Minerals and Metals Minerals are intrinsic to the residential, municipal, communications, and transportation infrastructure of modern life. Examples: Hybrid motors - nickel hydride batteries Water purification systems ? nickel, rare earth elements Catalytic converters - cerium Screens and monitors - several rare earth elements Clean electricity - uranium Circuitry - gold, copper, aluminium, lithium, titanium, silver, cobalt, zinc Instruments - copper, silver, nickel, cobalt, copper, brass Protective products ? zinc, calcium carbonate, sulphur

May 1, 2008

The Devonian Mount Morgan gold-copper deposit was situated on the western margin of the Calliope Volcanic Are assemblage, in the northern New England Orogen. Recorded production from commencement of mining in 1882 to mine closure in 1989 stand

Jan 1, 1994