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By Dr. Jack M. Gillette

A system of models which simulate surface coal mining operations has been developed for use in mine planning and economic evaluations. Micromodels simulate individual mine operations for equipment selection and mine planning. Macromodels simulate all operations in the complete mine for economic evaluation of reserves. A cash flow analysis model makes a complete discounted cash flow analysis to deter-mine a required coal sales price or return on investment for evaluation of any mining project.

Jan 1, 1978

By John Hanna

Recently. researchers at The University of Alabama have developed a two-step method for the treatment of phosphorus sludge that includes bulk removal of phosphorus by physical separation techniques followed by remediation of the residual P4 in the sludge using a novel wet air oxidation technique known as "HSAD", Tests made on samples of the electric furnace phosphorus sludge have demonstrated that essentially complete and fast removal of the P4 in the sludge can be achieved by the HSAD wet oxidation treatment, Further studies were made to determine the applicability of the two-step process on sludges of various origins. P4 contents different pre-treatment and storage conditions, The present work discusses the mechanisms and factors controlling the HSAD wet air oxidation remediation approach.

Jan 1, 1992

By P. Mišcevic, B. Kavur, I. Vrkljan, N. Štambuk Cvitanovic

It is known from earlier and recent research that mechanical properties of intact rock like uniaxial compressive strength (UCS), Young's modulus (E) and Poisson's ratio (?) are influenced by shape deviations of test specimens as deviations from the ideal cylinder. That impact can be significant at certain level of inaccuracy of specimen preparing, and it should be objectively evaluated and controlled in testing. The effects of intact specimens side straightness, ends flatness, ends parallelism and perpendicularity to the specimen axis, on UCS, E, and ?, measured in several actual ways during laboratory compression tests, were determined by previous research on 90 homogeneous specimens of limestone. In this paper, we subject these new experimental results to Response Surface Methodology (RSM) to model the mentioned dependence, to identify significant connections of variables and to evaluate the conclusions obtained directly from experimental phase. This study indicates how the responses of the model (outputs) – parameters UCS/E/??of limestone rock depend on factors (inputs) – parameters of specimen shape deviations like flatness R, parallelism P and perpendicularity O, assuming modern test machines with spherically seated upper platen. Starting from general RSM model with three factors (R, P, and O), we investigated the multiple linear regression models of specific mechanical property (UCS, E, and ?). Using the NCSS program ("NCSS 2004 and PASS 2005") in several steps, final models with very high coefficients of determination were developed for properties with the most evident effects of specimen shape deviations: nine models for strength UCS and UCS50 (equivalent UCS for specimen with 50 mm diameter), and three models for ?L (Poisson's ratio calculated from axial deformations measured on the entire specimen length). These statistical models with their response surfaces further strengthen and confirm the results and conclusions from the experimental phase. The critical values of R, P, and O are established using an additional statistical analysis to determine the lower and upper engineering limits. These findings set the basis for the new eligibility criteria for specimens of limestone (and similar rock with UCS about 100-150 MPa) in further testing of strength and deformability.

Jan 1, 2015

By P. M. Hawley

Kennecott Corporation, in joint venture with Galactic Resources Ltd., recently began operation of an open pit gold mining and milling facility near Columbia, South Carolina. The deposit consists of two ore bodies (North and South deposits) hosted in deformed and altered meta-volcanics and meta-sediments of the Carolina Slate Belt. This paper describes the rock mechanics and engineering geology investigations conducted for design of interim, ultimate and final reclamation slopes for the South Pit. Emphasis includes the successful use of drill core orientation techniques to confirm complex geologic structure at depth; the development of a three-dimensional rock mass competency model, incorporating surface mapping data, results of bench mapping documentation, field index testing and laboratory testing; and kinematic assessments for design of optimum slopes.

Jan 1, 1991

By J. W. Town

The Bureau of Mines conducted petrographic classification and flotation studies to determine if acid-grade concentrates could be obtained from individual and composite samples from the Meade Peak member of the Phosphoria Formation, Idaho. The petrographic studies were made to determine the effect of compositional features on concentration of phosphates. The ore grade, ovule size, and clay content were the main features affecting grade and recovery of phosphate. Flotation results on roasted ore with a tall oil emulsion scheme showed that beds containing over 10 percent P2O5 could be beneficiated and composited with the two high-grade beds to produce a composite concentrate containing 31.9 percent 05 at 84.3 percent recovery. Treatment of these intermediate-grade phosphate beds by flotation increased ore reserves over 200 percent and increased the ore-to-waste ratio in the ore zone from 1:5.7 to 1:0.27.

Jan 1, 1966

By M J. Daniel

The diamond industry is no newcomer to High Pressure Grinding Rolls (HPGR) as it has used the technology for more than 20 years, predominantly in secondary crushing and recrushing roles. In fact it could be argued that the diamond industry has led the way for the wider minerals industry to consider its application. In existing conventional secondary cone crushing applications, large valuable diamonds are" won" through meticulously managing the recovery process within defined particle size ranges. Conventional crushers operate with relatively large closed side settings, but have the potential to damage diamonds by making direct contact with the sides of the crusher. Cone crushers also result in steep product size distributions that run a high risk of losing many of the smaller, unliberated but more abundant diamonds from the rock. This current comminution paradigm of particle size reduction management results in recrushing processing applications or plants where HPGRs are often used.

Jan 1, 2010

By H. W. Davis, W. W. Adams, O. E. Kiessling

"Current economic problems frequently have focused attention upon the lack of adequate quantitative information indicating the relationship between human effort and output in various branches of the mineral industry. With the exception of complete records covering coal mining, only scattered information on the units of human energy required to produce a unit of raw material is available for most of the important industrial minerals. Fortunately a virtually complete statistical record is available covering this phase of the iron-ore mining industry.For many years iron-ore mining companies, whose interest in safety work is well-known, have reported annual data on employment to be used in the compilation of accident statistics. These data on hours of labor and other detailed employment information have been correlated with the statistics on production also reported annually by producers. The outstanding trends shown by this composite record for the 10-year period 1923-32 are included in the following discussion, supplemented by a summary table that presents the principal statistical background of the study. 5The substantial reduction in the number of men needed to produce the annual iron-ore requirements of the United States, as shown strikingly in the graphs, illustrates that in iron-ore production improvements in technology have been consistently winning a battle over the difficulties of nature. In 1923, for example, 41,294 men working 107,551,244 hours were required to produce 69,351,442 gross tons of merchantable ore, equivalent to an average output of 0.645 ton per man-hour. In 1929, however, only 30,763 men working 77,111,686 hours 'zero required to produce 73,027,720 tons of merchantable ore, equivalent to an average output of 0.947 ton per man-hour. Thus, from 1923 to 1929 the average number of men working decreased 25.5 percent and the total man-hours worked 28.3 percent, while the average output per man-hour increased 46.8 percent and total merchantable ore production 5.3 percent."

Feb 1, 1935

By J-M M. Rendu

Geostatistics are increasingly recognized as powerful tools for reserve evaluation and grade control. It is also generally accepted that geologic input is required for the results of a geostatistical study to be meaningful. The role of the geologist is significant at all stages, whether it be to oversee the creation of the database, to assist in the statistical and semivariogran studies, to ensure appropriate block evaluation and kriging, or to review the results obtained. However the link between geology and geostatistics is often complex and not well understood. A presentation is made of the areas where geologic input is needed, and of the tools which the geologist should have at his disposition to ensure that his role is fulfilled. Organization of a Geostatisticel Study To be acceptable as the basis for financial investment, a geostatistical reserve estimation should be composed of four phases, the last phase being optional: Phase 1 - Background discussions, Phase 2 - Computation, Phase 3 - Reserve reporting, Phase 4 - Reserve audit. During the background discussions (Phase 1) the role of the geologist is primordial, as it is then that most decisions will be made concerning the geologic factors to be included in the geostatistical model.

Jan 1, 1985

By H R. Phillips

Fresh air intake in an underground coal mine is of critical importance to the occupational health and safety of workers due to the dynamic, confined and dangerous nature of the mining environment. In most coal mines in South Africa, belt road is not separated from the fresh air intake to the sections. Intake air to coal production faces generally contains dust generated by conveyor belts, transfer points and travelling roads. Long roadways (up to a few kilometres in some of the existing mines) to the coal sections are involved in the ventilation circuits of individual sections. This leads to a progressive increase in the dust levels in the intake fresh air and thus high dust levels in the air delivered to the working sections downstream. In the process of reducing worker exposure to dust in the face area, attention to the monitoring of fresh intake air is generally given a low priority. This paper summarises the intake dust levels measured in selected South African underground coal mining sections over the past five years and its use as a parameter in assessing worker exposure to dust through a newly developed model called the Dust Exposure Level Index (DELI). Based on the measured data of the South African coal mines, the average section intake dust level was 0.78 mg/m3. Approximately 60 per cent of the samples collected for the study have exceeded the 0.5 mg/m3. The intake dust level measured at a longwall face was much higher than in the CM headings. The measured section intake dust levels furnish the South African coal mining industry with the latest depiction of the level of face area dust contamination due to the intake air. Further, this paper demonstrates the use of intake dust level as a parameter in estimating exposure levels of workers, as it clearly plays as a corner stone in effective control of exposure to face area respirable dust. It must be borne in mind that intake dust is a base level to the mine worker exposed to dust without carrying out any additional work in the section. If the intake air is seriously contaminated by airborne respirable dust; then the exposure of the workforce in the section will constantly be elevated by that background dust level.

Jan 1, 2005

By L. Makua, K. Langa, Ndlovu. S., C. Saguru

"Global demand for the three platinum group metals (PGMs) Pt, Pd, and Rh has been steadily growing due to their widespread use in emission control, industrial catalysis, and numerous other applications. The primary supply of PGMs is currently the mining industry. However, legislative, operational, and environmental challenges faced by many mining operations result in erratic supply patterns and deficits for these three metals. Naturally, recycling scrap material to recover Pt, Pd, and Rh has therefore aroused research interest in the scientific and engineering communities. Given that the majority of the global demand for these three metals is driven by emission control devices, autocatalytic converters are therefore a significant source of already processed and beneficiated PGMs for recycling.Although pyrometallurgical processes dominate the recycling industry, hydrometallurgical processes may offer certain advantages, chief among these being lower emissions and reduced energy consumption. In this investigation, scrap converter material was leached in acidic chloride media and the leach liquor subjected to solvent extraction and cloud point extraction (CPE) to recover the PGMs. The recoveries for Pt and Pd using Alamine 308® dissolved in kerosene with decanol as a modifier were 95% and 81%, respectively. The maximum recoveries using CPE after complexation with 2-mercaptobenzothiazole (2-MBT) in the presence of Triton X-100 and tin (II) chloride dihydrate as a reductant were 97% for Pd, 96% for Pt, and 91% for Rh. This demonstrates that CPE, although relatively new, may have some potential as a breakthrough PGM recovery technology. IntroductionPlatinum group metals (PGMs) have found a wide variety of applications in different industries due to their chemical, catalytic, and physical properties. PGMs are essential in automobile emission abatement, petroleum refining, and the pharmaceutical and electrical industries (Carabias-Martinez et al., 2000). However, the abundance of PGMs in the Earth’s crust is low and their primary sources are fast depleting (Crundwell et al., 2011).The high demand for PGMs, together with social, economic, environmental, and political aspects related to their production, has led to concerns about their future supply. This has resulted in renewed interest in recycling end-of-life material. PGM supply from recycling has doubled over the last decade, and currently contributes 22% to global supply (Johnson Matthey, 2016). This is in part due to the environmental, social, and operational challenges associated with mining of PGMs. For example, labour unrest, energy cuts, declining commodity prices, and declining ore grades have collectively made the mining landscape economically challenging (KPMG, 2015). On the other hand, the high content of PGMs in secondary sources makes their recovery from the increasing quantities of waste products important from a resource conservation viewpoint. Moreover, PGMs obtained through recycling have been demonstrated to have a 1% environmental cost from a life-cycle perspective, whereas PGMs obtained from mining contribute the remaining 99% of environmental cost (Bossi and Gediga, 2017). Sustainable resource recovery and the economic incentive of recycling have therefore been major drivers to justify investment in PGM recycling. The autocatalytic converter industry accounts for about 70% of the global consumption of these metals (Johnson Matthey, 2016) and therefore recycling spent converters has become a major source of Pt, Pd, and Rh (Figure 1)."

May 1, 2019

By P. Bakke

Following extensive R&D efforts, Hydro Magnesium has launched a new alloy series with remarkable combinations of properties. The AE alloy family is based on additions of aluminium and rare earth elements to control mechanical properties, including elevated temperature creep strength. By combining these alloying elements with manganese additions, high purity alloys with outstanding corrosion performance are defined. A basic philosophy behind the developments has been to simultaneously approach all the critical issues related to developing a commercial material. Apart from the obvious requirements for material properties, the critical issues relate to die casting performance, as well as alloy production, recycling and environmental compatibility. Some of the important elements related to alloy production and recycling are addressed in the present paper.

Jan 1, 2006

By P J. Hawke

Within the Mesa J pisolitic iron ore mine, clay is distributed unevenly throughout the deposit and often forms as pods and channels less than 10 m in width. The mine resource model, based on 50 m + 50 m spaced drilling, has been unable to accurately delineate the clay for scheduling and mining purposes. Therefore, alternative methods for mapping the clay-contaminated ore were sought. Predictive clay mapping will significantly reduce production costs at Mesa J through improved selective mining practices, more accurate scheduling, reduced wear on mining equipment and minimising the need for maintenance of haul roads and ramps. High lateral resolution electromagnetic (EM) surveying using a Geonics EM31 instrument can quickly and inexpensively delineate the extent and orientation of the clays. Preliminary results indicate that a block model based on the interpretation of the EM data can accurately predict the distribution, volume and tonnage of ore and waste material. While rip-line mapping, infill drilling, ground penetrating radar and gravity can delineate clay with various degrees of success, none were as efficient as EM31.

Jan 1, 2002

By C. J. Preston, R. E. Ström, G. R. Baiden

"On January 1st 1996 Inco Limited, Tamrock OY, Dyno Explosives Group and CANMET formed a consortium for the development of robotic mining equipment. This project is a five year research and development agreement that combines the talents of the above organizations to facilitate the creation of mining equipment and systems for robotic mining.The projects are based on the communication system developed by Inco Mines Research and currently sold and marketed by Automated Mining Systems Limited. Main projects include the development and implementation of a positioning and navigation module (including a software mapping system that will be inherent to each piece of equipment), robotic systems for development and mining, and software systems to support the use of this equipment. Included in the program is the establishment of a test mine, at Inco’s 175 ore- body at Copper Cliff. This facility will allow collaboration of companies and research organizations for the design and testing of techniques and equipment for Robotic mining.This paper discusses the creation of this new research alliance, the Mining Automation Program or MAP."

Jan 1, 1997

By J. C. Motz

With ore grades continually decreasing and finer mill feed requirements, it becomes increasingly important to have the capability to handle the larger tonnages economically. With the 10 ft. Standard capable of reducing 1,633 metric tons per hour (1,800 short tons per hour) to 80 percent passing 50 MM (2 inches) and the 10 ft. Short Head following to produce a mill feed of all minus 12 MM (1/2 inch) at a rate of 608 metric tons per hour (670 short tons per hour), we feel significant savings will be realized in installation and operating costs. The largest concentration of cost in the secondary and tertiary crushing stations is the building itself that houses the process equipment. An example of the savings to be attained can be seen from an examination of a 40,820 metric ton (45,000 short ton) per day crushing plant. A total of nine 7 ft. Symons Cone crushers is used to generate 12 MM (1/2 inch) ball mill feed. The average center distance between units is 6.1 M (20 feet) and allowing a 6.1 M (20 feet) nominal distance from the centerline to the wails, the building becomes 61 M (200 feet) long. For this production rate, four 10 ft. Symons Cone crushers would be required. With the 10 ft. crushing plant requiring a center distance spacing of 7.6 M (25 feet), the building length totals approximately 38 M (125 feet). Construction costs vary depending on location, but a reduction in building length from 61 M (200 feet) to 38 M (125 feet) will result in estimated savings of between $2,500,000 and S4,000,000. While the 10 ft. Symons Cone has been involved in a number of feasibility studies for some time, the Process Machinery Division of Rexnord commenced detail design work on the 10 ft. Cone crusher in 1972. For comparison purposes, the 10 ft. and 7 ft. capacities are given in Table 1.

Jan 1, 1978

By M. Turek

Cost management in the conditions of increasing competition and unforeseen market turbulence constitutes one of the key areas of the enterprise?s activity. In the last two years the demand for hard coal on the domestic and global market of non-renewable resources has increased significantly. Polish hard coal mining industry, as an industry in the stage of decline, received a chance for rejuvenation. However, one of the most significant conditions of seizing this opportunity is the rationalization of mining costs and improvement of production effectiveness. Due to the significance of this issue, the main objective of the paper is to identify the possibilities of improving the production effectiveness in the hard coal mining industry. In order to meet such an objective, in the first part of the paper we measured effectiveness in the Polish hard coal mines in years 2006- 2011. The research encompassed three out of five mining enterprises operating in the country. Then based on the received results, guidelines concerning the improvement of effectiveness of production were created, taking into consideration infrastructural, technical, economic and organizational determinants. Furthermore, opportunities and threats for improving the production effectiveness, stemming from the external conditions have also been indicated.

Aug 1, 2013

By Robert H. Ridgway

Chromite has been produced commercially for slightly more than a century. Developed, at one time, chiefly as a chemical pigment raw material, it has subsequently found extensive application in other chemical industries - as a refractory material for furnace linings and as the sole source of the metal chromium. For some years prior to 1914, its use as a refractory predominated; but post-war development in alloy steels, principally stainless steels, enhanced the metallurgical demand in the form of ferrochrome with a consequent increase in the demand for chromite. More recently direct reduction of chromite in alloy-steel manufacture has been applied to a limited extent. Alloy steels containing varying amounts of chromium, with or without other alloying elements, now find extensive use in a ride variety of ways - in structural material, machines, industrial equipment transportation by land, sea, and air, sanitary equipment, food preservation, and a multitude of other uses. In recent years chromium plating has had wide application and has become important. industrially, but the amount of raw material consumed

Jan 1, 1936

By James Giulianelli

Personnel at the Jet Propulsion Laboratory (JPL) are studying the technology and applications of salt-gradient solar ponds (see below) for both electrical and thermal energy generation. The brine extraction and processing site operated by the Kerr-McGee Corporation at Searles Lake, California, offers ideal conditions for economic construction of solar ponds. Furthermore, since rising conventional energy costs adversely affect the economic recovery of brine by the present process, this site was selected for a study on the feasibility of integrating the solution mining of trona (Na2CO3?NaHCO3?2H20) in the lower salt with solar ponds for heating. The major emphasis of this study was to determine whether inexpensive thermal energy available at the brine extraction site would be useful in extracting increased mineral value from the resource. The present operation, which involves the simple extraction of the complex brine and its processing at the adjacent plant, is sometimes referred to as solution mining. Since the concept discussed in this paper involves injecting a heated sodium sulfate brine to dissolve carbonate underground, the proposed scheme is referred to as "enhanced" solution mining. The subject is discussed in greater detail in a recent JPL report. (1)

Jan 1, 1981

By Joseph F. Davies

Along with the humanitarian need for preventing accidents the cost of injuries must be considered. As a means of bringing the facts concerning the prevalence of accidents in mining and their direct cost before the operating officials and others interested in accident prevention in the mining industry, the United. States Bureau of Mines ha as recently made studies and published reports dealing with these subjects in several States 4. This report gives available data on the causes and direct costs of accidents in Virginia coal mines for the 4-year period 1929 to 1932, inclusive. Mounting compensation costs and insurance rates resulting from mine injuries indicate the necessity of measures to decrease the number and severity of accidents. These direct costs, as well as additional losses of an indirect nature, can be eliminated from the cost of production to the extent that accidents are prevented or reduced in severity.

Jan 1, 1934

By R. A. Campbell, R. R. Rogers

"AbstractThe experiments described show that crude bismuth metal containing up to 5 per •cent lead, 0.14 per cent silver, 0.015 per cent copper, 0.02 per cent iron, .and small amounts of antimony, nickel, and tin may be refined to a bismuth content of 99.98 per cent by distillation followed by chlorination. It also is shown that bismuth trichloride of high ,purity may be produced by passing chlorine over hot •crude bismuth metal and allowing the resulting vapours to •condense in a cooler .part of the system.IntroductionBISMUTH is used in the production of alloys and pharmaceuticals. During 1952, the New York price for the refined metal was $2.25 per pound in ton lots.Some months-ago a Canadian producer requested the Mines Branch to investigate methods of refining the bismuth which they had been producing. Their crude product had been selling for $1.50 to $1.70 per pound and it was desired to increase its purity to at least 99.98 per cent so that it could be sold for $2.25 per pound."

Jan 1, 1955

By C. J. Newman

Prior to 1995, the smelting process at the Kennecott Utah Copper Corporation (KUCC) smelter consisted of Noranda reactors and Pierce-Smith converters. In the consideration of expansion opportunities, the existing process did not lend itself to a program geared towards processing the total output of KUCC mining and milling operations. During 1989 and 1990, a number of smelting options were evaluated. The final selection was the Outokumpu flash smelting process, coupled with the new Kennecott-Outokumpu flash converting technology. Facilities were designed and installed to process 1:0 million tonnes per year of copper concentrate, with the ability to expand to 1.2 million tonnes per year. Following the shutdown of the smelter facility utilizing the Noranda technology in May 1995, the flash smelting, furnace commenced operation in June with the flash converting furnace startup following a few weeks later. The smelter has achieved design production targets and environmental goals. Current operating rates are at or above design rates for concentrate and matte processing. Emissions are lower than the permit levels and equate to less than 3.5 kg of SO2 per tonne of copper. This paper outlines the design, construction, startup and the first two years of operation of the modernized KUCC smelter.

Jan 1, 1998