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By H. Kasaini

Batch wise adsorption tests for platinum (Pt) on the surface of activated carbon pellets (Norit RO 0.8 BET surface area 1100 mg/g) were carried out in mixed chloride solution. The purpose of this study was to assess and compare the adsorption performance of amine-treated activated carbons (AACs) and native activated carbons (NACs) in terms of adsorption capacity and selectivity. The effect of pH and temperature on adsorption capacity and selectivity was established. The amine- treated ACs were prepared by anchoring the amino groups (butyl amines) on the surface of AC pellets in aqueous media and the UV-Vis was used to determine the amount of amine sequestered from solution by ACs. The dosage of butyl amine on the surface of ACs averaged 0.15 g/g, carbon. The adsorption mechanism was described by the ionization and complexation model whereby interaction between the protonated AAC surface and the anionic chlorocomplex ions (PtCl5 [H2O]-, PtCl62-) proceeded by either electrostatic attraction or/and by covalent bonding [(NH3)2PtCl6 or (CH2COO)2PtCl6]. By comparison, the adsorption capacities of Pt on amine-treated ACs and native ACs were 53.8 mg/g and 33.03 mg/g, respectively which highlight the benefits of anchoring functional molecules on ACs. The selectivity of AACs was influenced by solution pH. Pt adsorbed selectively on the surface of amine-treated ACs at pH<1.5. The highest separation factor that was recoded pertained to Pt and Fe species (ßPt/Fe = 90) then followed by Pt and Ni species (ßPt/Ni = 30) or Pt and Cu species (ßPt/Cu = 15). The lowest separation factor was recorded for Pt and Cr ions (ßPt/N= 5). Adsorption kinetics of Pt on amine-treated AC surfaces, according to the first and second order reactions, were investigated and results showed that rates were in the order 10= 5). -4 min-1 and 102 g?min/mg, respectively. The pseudo 1st order kinetics predicted the adsorption capacity of 51.81 mg/g which was almost similar to the experimental value (53.8 mg/g) while the second order rate equation predicted Pt adsorption capacity of 40.1 mg/g. Both The Langmuir and Toth isotherm fitted the Pt adsorption at pH < 1.0. The Freundlich isotherm tended to underestimate the adsorption capacity of AACs.

Jan 1, 2014

By J. R. Soule

"The fluorspar deposits in the Gallinas Mining District, Lincoln County, New Mexico, were examined early in February and again in April 1943 by the Bureau of Mines because of the possible importance of newly discovered deposits and of old mine workings showing fluorite-bearing material. There &re many of these deposits spread over a considerable area, and it appeared that exploration might indicate sufficient reserves to support a local mill that could contribute to the supply of fluorspar needed for war purposes. Accordingly, the Bureau initiated an exploratory program in June 1943, which was completed in August 1944.H. E. Rothrock, Roy Earhart, R. G. Smalley, and V. C. Kelly, geologists of the Federal Geological Survey, began mapping and studying the district in May 1943 and continued this work throughout the Bureau's exploration.David J. Stauffer, district ranger, U. S. Forest Service, and several claim owners assisted in the examinations and subsequent exploration.The fluorspar deposits in the Gallinas Mountains are reached by an unpaved forest road, which, leaves U. S. Highway 54 half a mile south of Gallinas station. The road runs due west for 3 miles, then turns due north just beyond the first cattleguard. This north branch is followed for 2 miles to a second cattleguard. There a left branch extends northwest up Red Cloud Canyon to the Red Cloud, and. All. American deposits; the right branch continues north for 2.miles past the Wade Porter ranch, to another left branch, which goes almost 2 miles west to the Hoosier Group deposits. The remaining deposits are reached by trail from either the Hoosier Group or, more easily, from the Red Cloud claim (fig. 1).The Hoosier Group is in sec. l9,, T.. 1S.,1 R. 12 E.; all of the other known ore occurrences are in secs. 13, 14, and 23 to 27, inclusive, T. IS., R. 11 E. All of the deposits are in the Lincoln National Forest and within the limits of a State game refuge. The nearest railroad loading point is Gallinas, Station on the Southern Pacific Railroad. Corona, the next station north of Gallinas, is a Mile or two farther from the deposits.Minor supplied, telegraph, telephone, freight, and express service, and limited living accommodations, Are, obtainable at Corona, 10 to 15 miles from the deposits of Carrizozo, N. Mex., 50 miles south."

Apr 1, 1946

By Behdeen Oraee

Constructing tunnels underground is generally described as a high-risk activity because conditions in the surrounding area tend to be unpredictable. This would and can create unique dangers in every situation. It is important to gain a deep understanding of the risks associated with tunneling in order to reduce the likelihood of their occurrence and severity of their consequences should they occur. For this to be achieved, different risks should first be evaluated and ranked according to their relative importance and criticality. The Amir Kabir tunnel is considered one of the most dangerous tunnels in Tehran, Iran, in terms of the risks involved in its excavation and their potential consequences. In particular, part T4 of the tunnel passes through a zone of different strata and also a compound of various soils. This paper studies part T4 of the Amir Kabir tunnel from a risk analysis and risk management point of view. In doing so, factors increasing total cost, causing delay in the project completion time, decreasing the operation rate and downgrading project quality were identified and ranked according to their importance using the aggregate primary index risk method. For this purpose, a comprehensive questionnaire was designed and completed by tunneling experts. By responding to the questionnaires, the experts determined the relative likelihood of occurrence of the studied factors and their potential consequences. As a result, the experts suggested several alternatives to reduce the risks involved in this particular study. Moreover, the experts completed new questionnaires whilst taking into account different alternatives. In the next step, the risks before and after applying the alternatives were compared. As a result of performing the said analyses, it was concluded first that the aggregate primary index risk is an effective tool in identifying the risks involved in such projects. Second, it was concluded that, by taking into account different alternatives when analyzing and ranking the risks, severity of the said risks can potentially be reduced. Also, by considering such matters when analyzing tunneling risks, the projects? efficiency can greatly increase as a result of reducing risks that threaten financial and human resources. The approach introduced in this paper, together with the methodology described, can be adopted by the mining design engineer in all similar situations. They will be of particular advantage in such methods as room and pillar mining, where the number of similar tunnels required is high.

Jan 1, 2014

By G. Granata, C. Tokoro, T. Kato

"The goal of this study was to evaluate the effectiveness of mechanochemical activation by planetary milling as method to enhance the recovery of cerium from rare earth ores. For this purpose, a weathered ore was first ground by planetary milling and then leached by sulfuric acid. The influence of planetary milling was investigated by assisting the experiments with X-ray absorption fine structure (XAFS) in cerium LIII-edge and inductively coupled plasma spectrometry to measure the concentration of cerium dissolved by leaching. Results showed that, by increasing the grinding time, although the particle size of the specimen increased due to agglomeration, the recovery of cerium significantly increased. This finding clearly indicated that a smaller particle size actually hinders the recovery of cerium. In particular, XAFS analysis revealed that the longer the grinding time, the more tetravalent cerium could be converted into trivalent cerium and such conversion, also called mechanochemical reaction was beneficial to the recovery of cerium. Based on the obtained results, it was confirmed that approximately 70% of cerium could be recovered by mechanochemically activated leaching of rare earth ores.INTRODUCTION Rare earth elements (REEs) are a group of 17 chemically similar metallic elements comprising lanthanides, scandium and yttrium. Since REEs have various unique physical and/or chemical properties, they have become essential materials for advanced application (Adachi, 2015). REEs used in industry are usually supplied as rare earth minerals. In the last decades, flotation, gravity separation, magnetic separation and leaching have been widely applied to recovery of REEs from rare earth minerals like monazite (Archana, Rekha, Manis, Jitendra, & Jin, 2015). Among these operations, leaching has been widely studied in the recent years to improve the state of the art (Archana, Rekha, Manis, Jitendra, & Jin, 2015; Xiao, Feng, Huang, Huang, Chen, Liu, Wang, & Long, 2016; Farzaneh, Fereshteh, & Ahmad, 2017). Aiming to enhance recovery of REEs from rare earth minerals, a possible advancement of leaching technology could be the mechanochemically activation of the ore by high-intensity milling (Alorro, 2016). In the mechanochemical activation, an improvement of the leaching performances can be achieved through high-intensity milling operations which result into a dramatic decrease of the mineral particle size with a consequent improvement of the physical kinetics of leaching. Furthermore, the high mechanical energy provided to the sample during milling can determine the rupture of the crystal structure of the mineral, thereby transforming it into a more leachable form."

Jan 1, 2017

By Arthur L. Murray

"Putting safety over , " using the accepted meaning of the word " Safety " as the elimination of personal injury , resolves itself into the prevention or disassociation of a combination of two distinct circumstances . Opportunity for accidents is afforded by conditions that are likely to cause injuries , but such injuries are effected only when the human body is placed in a position to be injured . As will be discussed later , in mining , as in most other industries , the degree of safety experienced depends upon the disassociation of these two circumstances , first , by making working conditions as free from hazards as possible , thus affording the minimum opportunity for accidents to occur , and secondly , the training of employees to recognize dangerous conditions and adopt measures to protect themselves and their fellow employees against injury . The responsibility for preventing accidents rests upon every person employed in an industry from the directing head down through the individual workers , and the safety of that industry will be proportionate to the extent that each member appreciates and accepts his individual responsibility . Hence , safety becomes decidedly a personal equation . Whether the personal equation will be so applied as to result in the greatest freedom from accidents , however , depends largely upon the initiative of those directing the industry . Putting safety over in a small mine presents the personal equation in a more intensified manner than the same endeavor in a large mine . Large mines , owing to their size and financial standing, can usually main ta in and support an effective safety organization with one or more directors who devote all their time to the supervision of safety work . Most small mines with a limited number of employees and limited capital can not afford and are not justified in supporting a paid safety organization , and must depend upon the close cooperation of their working force in maintaining safe working conditions . On the other hand , if proper supervision is exercised the small mine has in some respects advantages not afforded by the large mine . The limited workings in a small mine should afford less opportunities for dangerous conditions to arise and permits more frequent inspection of the entire mine . The small working force permits more latitude in the selection of employees known or believed to be either safe workers or amenable to safety educational work. Likewise , a small working force facilitates the carrying on of safety educational work and allows a closer personal contact between the superintendent and his employees .

Mar 1, 1923

By Faruk Oksuz, Dave Schiemann, Matt Trotter, Mike Padilla, Carmen Scalise, Miquel Sanchez

"The McCook Main Tunnel system consists of a 10-m (33-ft) finished diameter, 490-m (1,600-ft) long, hard rock tunnel constructed from a 27.5-m (90- ft) diameter and 92-m (300-ft) deep main gate and tunnel construction access shaft. The gate shaft houses six, high-head 4.4 m by 9 m (14.5 ft by 29.5 ft) wheel gates to be installed in the bifurcated and steellined section of the tunnel. The tunnel also includes portal and energy dissipation structures as it daylights into the reservoir.The construction of the tunnel system has been divided into two contracts. The gate and construction access shaft was completed in August 2011. The tunnel excavation and concrete and steel lining was completed in September 2014. The remaining and undergoing construction include the tunnel connections to the reservoir and the Mainstream Tunnel and installation of gates and hydraulic cylinders. This article focuses on the live connection of the McCook Main Tunnel to the Mainstream Tunnel that was initiated in November 2014 and will continue through the seasonal drier weather conditions in Chicago approximately from October through April. Chicago TARP systemThe MWRD has been addressing combined sewer overflows (CSO) and flooding in Chicagoland since the late 1960s and formally adopted the tunnel and reservoir plan in 1972 to protect the region’s most precious drinking water supply, Lake Michigan. Phase I of TARP, which included construction of 175 km (109 miles) of deep storage and conveyance tunnels with diameters up to 10 m (33 ft), was completed in 2006. In addition to protection of Lake Michigan from CSO discharges, Phase I resulted in substantial improvements in surface water quality as well as the quality of life for lake and riverfront communities in Chicago. Water quality improvements and flooding mitigation will be further enhanced as Phase II reservoirs are placed in service, including the three large reservoir systems, McCook, Thornton and Majewski (Fig. 1).The McCook Reservoir is the largest reservoir in the TARP system. Once completed, this $700-million reservoir facility will receive 38 billion L (10 billion gal) of CSO and flood water via the McCook Main Tunnel, which connects the TARP Mainstream Tunnel to the McCook Reservoir, and from distribution and Des Plaines inflow tunnels which will bring flow from the Des Plaines Tunnel of TARP."

Sep 1, 2016

By S. G. Britton

"INTRODUCTION Strategies to improve performance in mining production, maintenance and mineral processing operations has evolved over time from straightforward time studies of individual machine performance in the 1960’s-1970’s to more sophisticated and better focused statistical and financial tools that have emerged in the 1980’s-1990’s . These newer strategies fall under the broad descriptive category of “Operational Excellence”. Operational Excellence is the term that embodies a number of performance evaluating strategies, the most popular and relevant to mining includes the following: • Six sigma for addressing errors within mining or milling process and work standards • Lean manufacturing to optimize organizational and operational performance through continuous improvement. There are other strategies that can be applied as well and this paper is not focused on a review of the pros and cons of any one strategy. However, the common threads in these strategies embody the expectation that expected results from these efforts can be quantified and that value will positively benefit the targeted work process, organizational unit, equipment deployment or time schedule when applied to it as part of continuous improvement efforts. The priority for proceeding with any one or more of these efforts is based on the calculated net value of the required resources to affect the change versus the estimated value gained. The practice is identified as the value mapping process. This discussion summarizes the value mapping process methodology used at a mature uranium mine and mill in northern Canada to work through the myriad of potential improvement efforts available through the operational excellence process for continuous improvement.THE RABBIT LAKE MINE AND MILL The Rabbit Lake Mine and Mill are located in northern Saskatchewan, Canada on the shores of Wollaston Lake (Figure 1).The mine was discovered in the mid-1960s and was built by Gulf Minerals, Ltd. The mill began processing uranium ore into yellowcake in 1975 from an adjacent open pit mine. A whole ore acid leaching followed by solvent extraction and precipitation forms the basic milling processes. The operation continued to produce yellowcake through a succession of open pits and finally opened an underground mine in the early 1990s. Since beginning production, over 200 million pounds of yellowcake has been packaged from the site, making it the sixth highest producing uranium mine of all time."

Jan 1, 2016

By Teruo Bitoh, Shogo Izumi

"The effect of B203 flux melting on the structure and the soft magnetic properties of the (Feo.1sBo.20Sio.os)96Nb4 bulk metallic glasses prepared by casting has been investigated. The ringshaped bulk specimens were prepared by the B203 flux melting and copper mold casting. It was confirmed that the flux melting promotes the precipitation of the a-Fe(-Si) and Fe2B phases in the central region of the specimens. The ring-shaped bulk specimens show a flat hysteresis curve, indicating a good linear relationship between the magnetic induction and the applied magnetic field. These results show that it is possible to develop a new soft magnetic material that exhibits constant permeability, which is necessary for producing inductors and choke coils.IntroductionSince the success of forming Fe-based bulk metallic glasses (BMGs) with good soft magnetic properties, great attention has been developed to synthesis and properties of the BMGs [l, 2]. The BMGs have high glass-forming ability (GFA) and, therefore, they can be used to prepare bulk amorphous alloys with a thickness of the order of a few millimeters by casting. The soft magnetic properties of Fe-based BMGs are better than those of ordinary amorphous alloys; therefore, these BMGs have wider applications as soft magnetic materials [3-5]. It is often required for soft magnetic materials that the shape of the hysteresis curve is changed according to the demands of applications. For example, materials with ""flat hysteresis curves,"" which means the magnetic flux density (B) and the applied magnetic field (H) show a linear relationship up to rather high magnetic field, are necessary for producing inductors and choke coils. Flat hysteresis curves can be easily achieved by creating an air gap in the magnetic path. However, magnetic flux leakage generated in the air gap inhibits high-density packing of the electronic components. In order to achieve flat hysteresis curves without creating an air gap, Fe-based ordinary amorphous alloys are subjected to crystallization by annealing and transformed into thin surface layers of a-Fe; the crystallization results in the compression of the remained amorphous phase [6]. Another way to achieve flat hysteresis curves is the formation of secondary phase (such as Fe2B) that act as pinning site of magnetic domain wall displacements [7]."

Jan 1, 2013

By Douglas B. Silver

"Editor’s note: Douglas B. Silver, Portfolio Manager, Orion Resource Partners, was the keynote speaker at the 2017 SME Annual Conference & Expo in Denver, CO on Feb. 19, 2017. He also gave the keynote address to the SME Annual Conference in 2008. The following is his 2017 keynote address with a few of the slides that were presented. The full speech is available on YouTube https://www.youtube. com/watch?v=uF0qwGJIX3UIn 2008, I had the privilege of giving SME’s keynote address. At that time the financial markets were on the verge of collapse and my presentation described the issues. Unfortunately I was correct, and global markets went into a steep nosedive, creating the largest economic downturn since the Great Depression.In hindsight, there were plenty of signs that this was coming. The Supercycle had created massive new wealth. This wealth was largely invested in the United States due to the country’s political stability and credit worthiness. In 2004, the large investment banks convinced the U.S. Securities Exchange Commission (SEC) to allow them to triple their borrowing leverage ratios. This made the banks more vulnerable to market volatility. The banks then lent money to NINJAS - people with no income, no job and no assets. Even worse was the fact that these unqualified home owners used adjusted-rate mortgages (ARMs) which they, of course, intended to refinance prior to interest rates rising. These mortgages were then bundled up by the banks and sold to investors as “safe” investment products. The money flowed into these products because the rating agencies gave these instruments high marks. These same agencies earned their fees from the very same banks seeking high ratings. (No conflict there). Private debt exploded and peaked out in 2008.These mortgage products were sold in an unregulated shadow banking system and the ARMs came due. Toxic mortgage default rates skyrocketed and the mortgage-backed securities collapsed in value. This house of cards had a negative feedback loop that accelerated the market crash and resulted in more than $1.5 trillion being lost in the securitization sector, a 47 percent decline in the Dow Jones Industrial Average, foreclosure rates skyrocketing and housing prices collapsing. The financial markets were in a nosedive."

Jan 8, 2017

By A. Monomakhoff

If a conductor traversed by an electric current is broken, a conduction forms in the air between the two broken ends of the wire. This conduction manifests itself in an initial phase by an electric spark and, in a second phase, by an arc if the the circuit continues to supply sufficient power. This arc goes out when the distance between the two ends of the conductor becomes sufficiently large. If the break occurs in an explosive atmosphere, the energy contributed by the arc can cause an explosion. To avoid such accidents, electric circuits that may be utilized in hazardous atmospheres can be made "intrinsically safe". The investigation which we conducted is part of a research project on the intrinsic safety of arcs of high intensity but short duration, in the case of resistive circuits. We developed an electronic system which makes it possible to limit the duration of an arc at the level of the break of a conductor traversed by a current with a possible maximum intensity of 80 amperes. This experimental device for monitoring and measuring the parameters of the arc has shown that arcs of high intensity but with a duration limited to a few microseconds do not ignite an explosive methane-air mixture.

Jan 1, 1975

By D. W. Heard

Electrospark Deposition (ESD) is a low heat-input, high energy density, micro-welding process. The short pulse duration and high-pulse frequency, in combination with the small amount of material transferred during each pulse, results in the evolution of extremely rapid cooling rates, believed to approach 105-106 °C/s [1]. This rapid solidification event results in the refinement of the microstructure to the nanostructured or amorphous level [2, 3]. Figure 1 displays the resultant microstructure of an Al-17%Si alloy deposited by the ESD process. Furthermore, it was determined that the microstructure of the deposit remained unchanged after subsequent layers were welded onto the presented layer. Freeforming of materials is a rapid prototyping process in which the deposited feedstock is built-up to the desired geometry in a near-net shape manner. Figure 2 displays the automated set-up employed produce three dimensional freeformed objects via multiple deposition trials of the ESD process. The automated XYZ table is equipped with CNC software to transform CAD renderings into three dimensional tool paths. Figure 3 displays an Al-12Si freeformed gear (2" diameter, 12 teeth) produced by the ESD process, prior to removal from the substrate. An SEM analysis of the freeformed component showed that the microstructure did not coarsen during the deposition of subsequent layers during the freeforming process, as depicted in Figure 4, resulting in the production of a bulk nanostructured component. This paper represents a summary of the capabilities of ESD to fabricate advanced materials possessing refined microstructure. In particular, results on the microstructural evolution obtainable for various wear-related systems will be presented. In addition, the feasibility of using the ESD process to freeform three-dimensional objects via multiple deposition passes will be presented and accompanied by a characterization of the properties of the freeformed component. [1] R. N. Johnson, "ElectroSpark Deposition: Principles and Applications," in Society of Vacuum Coaters, 2002, pp. 87-92. [2] J. Milligan, D. W. Heard, and M. Brochu, "Formation of nanostructured weldments in the Al-Si system using electrospark welding," Applied Surface Science, vol. 256, pp. 4009-4016. [3] S. Cadney and M. Brochu, "Formation of amorphous Zr41.2Ti13.8NilOCul2.5Be22.5 coatings via the ElectroSpark Deposition process," Intermetallics, vol. 16, pp. 518-523, 2008.

Jan 1, 2010

By M. Hertzberg

The Bureau of Mines measured the energy requirements for the spark ig-nition in air of Pittsburgh seam bituminous coal dust, lycopodium spores, and polyethylene powder with a 1.2-L furnace and 8-L and 20-L chambers. Thermal autoignition temperatures of the same dusts were mea-sured in the 1.2-L furnace. Electrical ignition requirements are given in terms of both effective spark gap energies, [ ] and stored circuit energies, 1/2 CE2. The measured order of electrical ignitability for the three dusts is consistent with the data of other researchers; however, the absolute values are systematically higher, probably because of higher flow and turbulence levels in the chambers used and lower electrical efficiency in the circuit used here. The temperature dependence of the lean limit of flammability for lyco-podium was measured wi th the 1.2-L sys tem, and those measurements con--firm the applicability of the modified Burgess-Wheeler law to a dust. Due to experimental complexities, the minimum ignition energies for dusts may not reflect intrinsic flammability behavior. However, some valuable information may be obtained from the relative ignition energies of various dusts at ambient and elevated temperatures. In addition, the concept of minimum electrical ignition energies for homogeneous gas mixtures is reevaluated theoretically.

Jan 1, 1985

By A. C. Smith

The U.S. Bureau of Mines evaluated the effectiveness of automatic water sprinkler systems on the suppression of incipient and propagating conveyor belt fires under ventilated conditions. Large-scale experiments were performed at airflows ranging from 1.1 to 4.6 m/s. In incipient fire experiments with 100°C, standard-response sprinklers installed above and between the belts, the sprinklers activated later, the peak heat release rates were larger, and more belting was consumed at the higher airflow. In similar experiments with 74 °C, fast-response sprinklers, the sprinklers activated at the same heat release rate for both high and low airflows, but the peak heat release rate and amount of belting consumed was slightly higher at the lower airflow. In incipient fire experiments with sprinklers located only above the top belt, the heat release rate and amount of belting consumed was larger at the higher airflow. The propagating fire experiments showed that sprinklers located above and between the belts were effective in stopping flame propagation. Peak heat release rates and amount of belting consumed were larger at the higher airflows for both the 74 °C, fast-response and 100 °C, standard-response sprinklers. The sprinklers were equally effective at each airflow.

Jan 1, 2010

By R. Krentz, P. D. Cordingley

The nickel-cobalt sulphides produced from limonitic laterite ores by Moa Nickel S.A. in Cuba are refined at the Corefco nickel-cobalt refinery in Canada. Major changes to the refining process were required when the Moa sulphide feed, with its unusually high cobalt content, was introduced in the early 1990&apos;s. In the period 1994 to 2005 the production capacity of the refinery has increased dramatically to match increases at Moa, and significant process improvements incorporated. The process flowsheet consists of the original ammonia leach process, optimized for cobalt chemistry and overall leaching capacity. Extraction of metal values is followed by the unique nickel-cobalt separation technology, in which most of the cobalt is separated from the ammoniacal nickel sulphate leach solution by precipitation as a nickel-cobalt hexammine salt. This salt is refined from a Co:Ni ratio of 1:1 to over 10,000:1 by selectively leaching nickel, redissolution and recrystallization in ammonium sulphate solution. Nickel and cobalt are recovered using the well-known Sherritt hydrogen reduction technology. This paper reviews the chemistry described above, examines some of the changes in operating conditions made over the years and highlights some of the recent physical changes made to the refinery.

Jan 1, 2005

By Patricia J. Leonard - Mayer

A Bureau of Mines surface resistivity method has been used to determine the joint strike and coefficient of anisotropy of jointed , nearsurface formations at five study areas . The field studies demonstrate the use of rotated , or azimuthal , Wenner-Lee arrays for determining the strike of predominant joint sets . The results of the field studies include the following : in a formation having a predominant , vertical joint set , the maximum value of the apparent resistivity ( pa ) occurs in the same direction ( azimuth ) as the joint strike ; the polar coordinate graph of pa for such a formation is approximately elliptical ; the coefficient of anisotropy ( ^ ) can be calculated from the field data , and values of λ for jointed formations are in the same range of values reported for layered formations ; values of λ are higher at mined sites than at unmined sites . The azimuthal resistivity method and horizontal profiling were used at a site in Pennsylvania to delineate a zone of intensely jointed and fractured bedrock that provided a flow path from a surface stream to a mine . Analysis of the data has been based on a simple model of a jointed formation having a single joint set ; the success achieved to date indicates the need for a more complex model and additional field data .

Jan 1, 1983

By W. R. Hardwick

This Information Circular describes copper mining and concentrating methods, practices, and costs at the Silver Bell Unit of American Smelting and Refining Co., Pima County, Ariz. It is one of a series being prepared by the Bureau of Mines on mining methods, practices, and costs in various mining districts of the United States. The Silver Bell mining district, one of the older districts in Arizona, is in the western part of the Silver Bell Mountains in Pima County, about 40 miles west of Tucson and about 20 miles southwest of Red Rock, a station on the main line railroad of the Southern Pacific Co. The Oxide and the El Tiro open-pit mines of the American Smelting and Refining Co. are in the district (fig. 1. The principal ore deposits are in T. 12S., R.8E., Gila and Salt River base line, at an altitude of about 3,000 feet. The present town of Silver Bell, established in 1952, is reached by a paved highway, the Avra Valley road, that turns west from Highway 84 at Plata siding near Rillito and extends westward 25 miles to the townsite (fig. 2). The present town is about 5 miles southeast of the old town of Silver Bell that flourished from 1900 to 1930.

Jan 1, 1963

By J. L. Eakin

Systematic flooding was introduced into Nowata County, Okla., in May 1931. The results of this means of stimulating the nearly depleted Bartlesville reservoir in the county has been the subject of four Bureau of Mines Reports of Investigations.2-5/ This report presents a discussion of four full-scale water-flooding projects in the Delaware-Childers field and 1 pilot project in the Curl Creek field (fig. 1). All five plants have been in operation for only a few months. Although substantial increases in the rates of oil production have been obtained 1 by the injection of water, the projects are of particular interest at this time because of the novel methods of operation and new equipment that are being employed. One project utilizes a portable "package" plant designed for a pilot operation. All of the controls for this project are centrally located. The design makes it possible to remove the test plant to another location if the project is unsuccessful or if the unit is to be replaced by a larger plant. This project also utilizes diatomaceous-earth filters successfully for the first time and makes use of plastic pipe. Another novel feature of the operation is the aeration of Arbuckle limestone water through an airlift in the supply well.

Jan 1, 1955

By W. R. Hardwick

This Information Circular describes copper mining and concentrating methods, practices, and costs at the Silver Bell Unit of American Smelting and Refining Co., Pima County, Ariz. It is one of a series being prepared by the Bureau of Mines on mining methods, practices, and costs in various mining districts of the United States. The Silver Bell mining district, one of the older districts in Arizona, is in the western part of the Silver Bell Mountains in Pima County, about 40 miles west of Tucson and about 20 miles southwest of Red Rock, a station on the main line railroad of the Southern Pacific Co. The Oxide and the El Tiro open-pit mines of the American Smelting and Refining Co. are in the district (fig. 1. The principal ore deposits are in T. 12S., R.8E., Gila and Salt River base line, at an altitude of about 3,000 feet. The present town of Silver Bell, established in 1952, is reached by a paved highway, the Avra Valley road, that turns west from Highway 84 at Plata siding near Rillito and extends westward 25 miles to the townsite (fig. 2). The present town is about 5 miles southeast of the old town of Silver Bell that flourished from 1900 to 1930.

Jan 1, 1963

By B. Arlyuk

On the basis of research of relations among the market participants the analytical model has been created which connects the price of industrial good at stock exchange with volume of sales and the stock of the sellers and buyers, Also a model was developed for assessment of these parameters of the market status by the actually fixed stock exchange and general market indicators. The composition of these models made it possible to create reliable system of short-term price forecasting for commodities or base metals up to one quarter ahead. Imperfectability of creation a model for reliable price forecasting by purely statistic methods (by the "black box" principle) was shown. A model of price behavior qualitative forecasting till one quarter ahead has been developed, which determines the probability of reaching in future of the given level as well as of the price maximums and minimums, Optimal values of threshold probability were determined for forecasting the future price maximums and minimums securing the maximum profit from the forecasting system application for commercial activity. The developed system of forecasting was identified for primary aluminium at the period of 1990-2003. The system was tested daily during 20 months period for speculations on 3M primary aluminium forwards at London Metal Exchange with high commercial result.

Jan 1, 2004

By Gene R. Reid

The contract objective is the development of an Automatic Fire Control System for Mobile Underground Metal Mining Equipment. The Phase I Report, which described the projected data handling plan, was published on July 24, 1975. The Phase II effort covered the period from July 24 through December 2 and accomplished the following objectives: ? Acquisition of data in accordance with the project data handling plan. Data were acquired through visits to twenty mine sites in ten states and Canada; visits to Bureau of Mines and MESA facilities; visits to mobile equipment manufacturers; and an extensive literature search. ? Analysis of accumulated data which provided the following specific types of design inputs: selection of the type of mobile underground equipment found to represent the greatest overall fire hazard; typical operating conditions for the vehicle; characteristics of the reported fire experiences; and performance, cost and maintenance factors affecting potential purchases of automatic fire control systems for underground mining equipment. ? Development of the AFCS design concept. Utilizing the data analysis results and considering the state-of-the-art of fire control system components, a recommended design concept was developed with particular emphasis placed on the need for a low cost and reliable system. Design trade-off studies are provided for the recommended system and for four alternate system concepts.

Jan 1, 1975