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By Clark D. Harrison

This paper compares the ash slagging potential of Illinois No. 6 Seam coal: as raw coal; as commercially cleaned coal processed in a baum-jig plant; and as coal cleaned to a reduced ash specification at the Electric Power Research Institute's Coal Cleaning Test Facility. The comparison is based on: ? ASTM ash fusibility data ? A slagging index ? Gravity fractionation analyses of critical mineral matter compounds ? Comparative pilot combustion tests. The first three grounds of comparison are laboratory data; and the final comparison involves burning approximately 15 tons of each coal at CONOCO's 1.5 MBtu/hr (440 KW) test combustor. The evidence of these .four comparisons indicates that lowering the ash specification of coal before combustion can significantly improve the ash slagging characteristics of Illinois 90. 6 Seam coal.

Jan 1, 1984

By Donald M. Ulbrich

As all of us know, the "heat" is on for western coal. The need for western coal is critical if the nation is to reach the goals of Project Independence by 1985. Without the development of western coal, the goals will not be met. It's that simple! That's because 50 percent of our nation's coal reserves lie in the states of North Dakota, Montana, Wyoming, Colorado, New Mexico, Arizona and Utah. And surface mining is the key to unlocking these reserves. Of the nine states in the coal provinces, five-Wyoming, Montana, New Mexico, North Dakota and Arizona-are the best examples since surface mining accounts for 88 to 100 percent of the coal mined in each of these states. Collectively, their annual production more than doubled between 1969 and 1972, rising to 35 million tons per year. And, taken individually, each state's production has more than doubled, also. Total annual production from these five key states could very well exceed 180 million tons per year by 1980-four times the 1972 production level. The biggest producer among the five is Wyoming. Wyoming's production tripled since 1969 to nearly 14 million tons in 1973. So the heat is on for western coal, especially from Wyoming. Now we come to the question of how to mine this increasingly precious mineral. What are the available methods? First, let's take a brief look at several characteristics of western coal deposits.

Jan 1, 1975

By Eugene Guccione

"All engineering societies should encourage and motivate their members to take part in public affairs. And engineers, in turn, should learn to translate their technical knowledge in a language which politicians can understand," stated James Boyd last month as he received the Hoover Medal, which is awarded annually by four engineering societies-AIME, IEEE, ASME, and ASCE-to an engineer who has rendered important public service. James Boyd is no ordinary engineer (see box). A few weeks ago, Dr. Boyd took time out of his busy schedule to stop at MINING ENGINEERING'S editorial office for the following exclusive interview.

Jan 1, 1976

By Adrian Moore, Dominic Hooton, Alan Richards

Significant factors affecting airblast overpressure (AOP) emissions include charge mass per delay, distance from the blast site, burden, stemming height, and delay timing, topographic shielding, and meteorology. The effect of charge mass on the frequency of the airblast produced, and the delay timing required to control the level of airblast overpressure is explained by two case history examples which were not affected by topographical shielding and meteorology. One is a cast blast with a charge mass per hole of 1000 kg (2200 lb), and the other is a quarry blast with a charge mass per hole of 64 kg (141 lb), These examples show that the delay interval necessary to prevent an increase in AOP levels must be increased with an increase in charge mass per hole. The effect of a ‘soft-start’ technique where a reduction in AOP levels is achieved by decking only the initial front-row holes is also illustrated.

Jan 21, 2025

By Chen Song

In the experiments of purifying the solution of chlorine leaching from nickel concentrate with N235, the effects of organic phase composition on purifying efficiency have been studied. From the results obtained, the optimal organic phase composition is found to be 25%N235+12%isomerous alcohol +63%sulfonic kerosene (VIV) and the saturated content of cobalt in organic phase is7.95 g*dm3. And then the serial experiment is carried out. The results show that at the given organic phase composition, the purified solution contains p(Ni) >200 gm dm3, p(Ni)l p(Co) >50000 and the contents of Cu, Fe, Mn, Zn meet the technical criterion of standard nickel electrolyte. The cobalt chloride solution contains p(Co) >I10 g L-1, p(Co) lp(Ni)>50000 and the enrichment of cobalt has been achieved.

Jan 1, 2006

By A. D. Garman

The mining ordinance of Costa Rica dates from 1830. In spite of the numerous attempts to enact a new ordinance , it has been so much amended and reamended during the hundred years of its existence either expressly or , more often , by implication , and sometimes by Executive Decrees of which the validity has been called in question - that in most cases no one but a lawyer thoroughly conversant with Costa Rican mining practice could properly advise with reference to it . The present attempt at a digest of these laws is based on the 1929 edition of Bolandi and Johanning - the only source available in Washington . Apparently this edition has no official character , and the editors themselves often made surmises although one would think that definite facts would be available in Costa Rica where it was published .

Jul 1, 1930

By A. Bauer, P. Katsabanis, M. Baker

The principal results from a previous paper presented at the Mine Accident Prevention Association of Ontario in 1987 (1) are summarized here. It is concluded that the selection of explosives in mines experiencing sulphide ignitions is important and that aluminized explosives should be avoided because of their high explosion temperatures and their detonation products. The duration of the blast is also critical and secondary blasts should not occur simultaneously with nearby priroa:ty blasts.

May 11, 1988

By N. E. Yasitli

There is a considerable amount of lignite reserve in the form of thick seams in Turkey. It is rather complicated to predict the characteristics of strata response to mining operation in thick seams. However, a comprehensive evaluation of ground behaviour is a prerequisite for maintaining an efficient production, especially when top coal winning by means of caving behind the face is applied. A comprehensive modelling of deformations and induced stresses is vital for the selection of optimum production strategy. In this study, numerical modelling and analysis of a longwall panel at Omerler underground coalmine have been carried out by using the software called FLAC3D developed based on the finite difference technique. Firstly, a 3-D numerical model of the M3 panel has been prepared. Secondly, induced stresses formed around the longwall face have been determined as a function of face advance where the face was located at the bottom of thick coal-seam. Results obtained from modelling studies have revealed that the front abutment vertical stress was maximum at 7 metres in front of the face and magnitude of front abutment stress was found to increase up to a distance of 200 metres away from the face start line. As the face was further advanced after 200 m from the face start line, there was not any significant change in the characteristics of front abutment stresses. Results of numerical analysis of the panel were in good agreement with in situ observations.

Jan 1, 2005

By Rose W. J

Geophysical prospecting was first recognized in Australia as an important aid to mining enterprises in 1927, when, on the suggestion of Sir Herbert Gepp, the "Imperial Geophysical Experimental Survey" was organized. The function of this survey was to carry out investigations on the applicability and efficacy of the most important geophysical methods under Australian conditions. The survey was formed under the joint auspices of the British Empire Marketing Board and Australian Commonwealth Government, and the investigations were carried out in Australia under the leadership of Mr. A. Broughton Edge, B.Sc., A.R.S.M., F.G.S., M.Inst.M.M., during the years 1928 and 1929. A description of the work performed, the apparatus used, the principles of the methods, and the results and conclusions of the survey are included in a report published by the Cambridge University Press in 1931.In 1932 Sir Herbert Gepp became interested in some gold mines in Eastern Victoria, in the Cassilis and Bethanga districts, and realizing that the lodes in these areas would be favorabIe for a geophysical examination, he arranged for a series of tests to be carried out. This work was performed by Mr. E. L. Blazey, B.E.E., a former member of the staff of the Imperial Geophysical Experimental, Survey, under the general direction of, and in consultation with, Mr. W. J. Rose, B.M.E.The work was commenced in October, 1932, at Cassilis, Vie., continued at Talgarno, Vie., .and concluded at...

Jan 1, 1933

By R. L. Bolmer

Rapid depletion of our known mineral resources has stimulated exploration for new mineral deposit. Abandoned mines or prospects may prove to be commercial in today's economy. Often it is necessary to revaluate such properties. Some of these may be inaccessible because of caving of flooding. Many, however, remain in good condition, except that over the years the air in the workings has become depleted of oxygen. Each year the Bureau of Mines receives numerous requests for aid in entering old mines, the air in which is incapable of supporting life. Requests of many individuals who wish to examine or explore-such places with the help, of the Bureau's self-contained oxygen breathing apparatus have been denied because of the hazards involved in the use of this equipment for such purposes. The distance to be traveled in irrespirable gases may be too great for safety; under favorable conditions, a round trip of 2,000 feet from fresh air is the maximum distance that may be traveled.3/ The use of such equipment is hazardous unless a team of at least 5 men thoroughly experienced in its use is provided; and when extensive traveling from. a fresh-air base is required, a reserve team should be provided.3/ Usually, the apparatus is requested for use in exploring workings having only one surface connection, as mines having more than one opening usually are more easily ventilated;,and in some natural ventilation is sufficient or can be made so by cleaning out obstructed openings.

Jan 1, 1951

By M I. Pownceby, J Manuel, S Suthers, A Poliakov, E Donskoi, N Ware

"The mining industry is constantly seeking methods for optimising the exploitation of mineral resources, such as iron ore, in a sustainable and eco-efficient manner for economic and social benefit. When faced with resources that have mineralogical or textural complexity, poorer grades or geological variability, it is particularly important to apply a comprehensive geometallurgical approach to the development of the mining operation, from resource definition through to processed product. Integral to this approach is the quantitative characterisation of representative samples across the whole orebody.A key factor that associates the geological characteristics of iron ores to their processing response is ore texture. While the classification of samples on the basis of chemical or physical properties alone is often not sufficient to predict their processing behaviour, classification and quantification of texture types can be effectively correlated to metallurgical performance in processes such as blending, beneficiation, pellet making, sintering and ironmaking. This paper describes some of the research conducted by CSIRO pertaining to the design and rationale of a texture-based classification system for Australian iron ores; some of the tools developed and used to apply such classification; and the application of the generated data to quantifying, modelling and predicting sintering behaviour and performance in the blast furnace.CITATION:Suthers, S, Pownceby, M I, Manuel, J, Ware, N, Donskoi, E and Poliakov, A, 2016. Geometallurgical Characterisation of Australian Iron Ores – from Ore to Processed Product, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 351–360 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By D Kentwell

A resource model serves two main purposes depending on the stage of a project. The first is to provide an early indication of likely tonnages and grades at certain cut-offs so that decisions can be made on whether continued spending on the project is justified. The second is to provide a basis for mine planning, feasibility studies and reserves. Resource models are not designed for selection of actual blocks in the ground for processing. This is the purpose of a grade control model, which is created at a stage beyond both resources and reserves.Inferred, Indicated and Measured Resources contain different levels of uncertainty with respect to the accuracy of the resulting grade and tonnage curves. These uncertainties arise from three broad areas: quality of information, geological assumptions and estimation technique. This paper focuses on known problems with the ordinary kriging (OK) estimation technique. Resource estimates often produce smoothed block grade distributions with much lower block grade variability than true selective mining unit (SMU) block grade distributions. There are two main factors that are involved in this smoothing. Firstly, where the block size used for estimation is larger than the SMU block size, this will smooth the block grade distribution and move the grade and tonnage curves away from the true SMU block grade and tonnage curves. Secondly, and less well recognised, is that smoothing is inherent in the OK estimator. This also moves the grade and tonnage curves away from the true SMU grade and tonnage curves, even when the estimate is done at the SMU block size. There are a number of techniques, such as simulation, uniform conditioning and degraded search neighbourhoods that can provide a better approximation of the true SMU block grade and tonnage curves at the expense of individual block accuracy.This paper aims to explore the extent to which OK resource estimates designed to maximise individual block accuracy can differ from (an estimate of) the true resource at SMU block size in terms of grade and tonnage curves. The differences at economic cut-offs and above are examined. In some cases these differences are significant. Both the OK estimation technique and block size play a part in the differences observed. To do this we will examine a number of commodities and deposit types using real project data.The conclusion is that the current industry standard default practice of targeting maximum individual block accuracy (conditional unbiasedness) using OK at resource stage, without consideration or evaluation of the extent of associated smoothing at SMU scale, can lead to significant errors in fundamental mine planning decisions. This then has implications for resource classification if the classifications are based heavily on the OK quality without consideration of the true SMU distribution.CITATION:Kentwell, D, 2014. Aligning resource estimates with mine planning, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 185–192 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By Bruce Bryant

Silver ore was discovered at Aspen in 1879, but the district did not reach full production until 1888 after lawsuits were settled and railroads furnished less expensive transportation to the outside world. The boom years were 1888-92; production declined thereafter. From the middle 1920's until 1950, the Midnight mine in the Richmond Hill district furnished most of the output in the Aspen quadrangle. Since 1950, little mining has been done at Aspen. The metals produced were silver, lead and zinc. Native silver dissolved from the sulfide ores was redeposited by waters circulating as deep as 300 m below the land surface, resulting in great secondary enrichment of many of the deposits. Over 100 million ounces of silver were produced in the Aspen quadrangle. Low-grade lead-zinc deposits remain between the old workings locally, and data available suggest that primary ore below levels mined is also of low grade. The ore occurs in the Mississippian Leadville Limestone and the lower part of the Pennsylvanian Belden Formation in sites that were made favorable for deposition by a number of stratigraphic and structural factors.

Jan 1, 1982

I. Domestic Production and Use: In 1981, 13 companies operated 32 primary aluminum reduction plants, with 3 firms accounting for 58% of production, Washington, Oregon, and Montana accounted for 32% of the total production; Texas, Louisiana, and Arkansas 16%; Tennessee, Alabama, South Carolina, and North Carolina 17%; other central and eastern States 35%. Based on published producer prices output of primary metal in 1981 was valued at over $7.5 billion. Aluminum consumption by 25,300 firms was centered in the East Central United States. Packaging accounted for an estimated 30% of domestic consumption in 1981, building 21%, transportation 18%, electrical la%, consumer durables 8%, and other uses 13%

Jan 1, 1982

By Donald Koch

The project investigated regional impacts of mining on the ground water system of the Powder River Basin by: 1) establishment of a regional ground water monitoring network, and 2)development of , set of digital computer models to simulate ground water flow and quality, ground water contributions to surface water flow and quality (i.e., baseflow), and watershed run-off and recharge. Over 100 wells were monitored for physical and chemical parameters. Data were used as input to the model; and for the development of a comprehensive data base. The basin was modeled on a regional and subregional scale using a finite -difference model employing an alternating difference technique. Two water-shed models were evaluated for their ability to provide runoff and recharge inputs to the basic ground water model. Application of the regional and subregional models using conservative mining scenarios showed that drawdowns may extend west from the mines as far as ten miles but that impacts would be insignificant on a regional scale. The watershed model could be effectively applied to small watersheds only.

Jan 1, 1982

By A. O. Ipsen

As part of the Bureau's intensive investigation of domestic manganese deposits, lots of ore for testing were collected by Bureau engineers during examinations of several properties in Juab County, Utah. One low-grade and two intermediate-grade samples (13.5, 25.3 and 27.5 percent manganese) were procured by engineers of the Bureau of Mines from the 900--and 1,100-foot levels of' the Tintic Standard mine, situated 2 miles southeast of Eureka, Utah. The ore bodies were described as blocks of ore approximately 60 feet long, 40 feet wide, and 20 to 100 feet deep. The manganese-iron association in the Tintic Standard ores was intimate, and no significant concentration of the low-grade sample was made by ore dressing, However, both of' the higher-grade samples were readily beneficiated to marketable manganese products. Ore from the Oxen No. 5974 claim, 2 miles northeast of Eureka, Utah was low in grade (19.4 percent manganese) and was not amenable to the production of high-grade concentrates owing to the intimacy of association of the manganese minerals with silica. However, a fair manganese recovery was obtained in a product that, when sintered, assayed plus 40 percent manganese. The ore body is reported to be a replacement in limestone and is composed of manganese oxides intermixed with silica, decomposed rhyolite, and limestone. The Fields property consists of five mineral claims situated 3 miles north of Eureka, Utah. The deposit is a replacement in a contact between limestone and a quartz dike. Tests were made on representative samples of a 50-ton lot stored on the property. Although the mineral association in the ore (22.2 percent manganese) is not particularly complex, the physical properties of the manganese minerals render the ore refractory to ore-dressing beneficiation. As the ores varied widely in physical and chemical characteristics, samples from each property were considered as separate ore-dressing problems.

Jan 1, 1949

By Phillip N. Yasnowsky

"In this Bureau of Mines report, the Federal income tax treatment of mineral exploration and development expenditures is summarized, and changes in the tax treatment of these expenditures since 1951 are detailed and analyzed. Although no attempt is made to establish causal relationships, major tax changes favorable to exploration and development activities did occur in 1951 and 1966 when the Nation was engaged in military actions and the economy was expanding. More recent changes have been unfavorable to exploration and development and were parts of major tax reform efforts. INTRODUCTIONThis Bureau of Mines report discusses the Federal tax law provisions relating to mineral exploration and development expenditures. These provisions, contained mainly in sections 616 and 617 of the Internal Revenue Code of 1954 (Title 26 of the U.S. Code), apply specifically to minerals (other than oil and gas), and thus are of interest to the Bureau of Mines.Bureau of Mines involvement in this subject stems from the legislative mandate in the 1913 amendments to the Organic Act of 1910 (the Act creating the Bureau) to conduct economic investigations of the mineral industries. Congressional concern with the financial conditions in the economic and mineral industries was expressed more recently in the Mining and Minerals Policy Act of 1970 and in the National Materials and Minerals Policy, Research, and Development Act of 1980. The General Accounting Office recommended in 1976 that the Department of the Interior ""identify and evaluate laws and agency programs that affect maintaining and developing a sound and stable domestic mining and minerals industry"" (17, p. iii). 2Taxes, a source of revenue to governments, are a cost to private firms. Thus, taxes directly affect private sector profits, and unique tax provisions are designed to encourage (or discourage) activities such as agriculture, construction, or mining. Even the international competitiveness of the domestic mineral industries may be affected by taxes because many minerals are traded in world markets."

Jan 1, 1985

By T Ireland, B Wright, S Weaver

All tunnels have unique characteristics that result in different fire and life safety risk. The fire safety systems for each tunnel also give different benefits at different costs. It is therefore neither pragmatic nor cost-effective to prescribe specific fire standards requirements for all tunnels. Each tunnel needs to be assessed individually but using a common process.The owner/client is normally the risk owner and needs to make the decision on what fire and life safety provisions will be provided within the tunnel. To make this decision they need to be appropriately informed. The low probability and high consequence nature of fire events creates a challenge such that traditional analysis processes, which tend to focus on a major event after it has happened, are not easily applied and do not give the best value for money. Therefore a process is required that provides the relevant information to the owner for decision-making.A quantitative risk assessment (QRA) provides a process and framework for the consideration of fire life safety risk when applied properly. This involves a risk assessment of the ‘do nothing’ option together with assessments of improvement options and their costs. It also involves consideration of benchmark safety levels for other tunnels and the open road.This paper will outline a QRA process for assessing fire and life safety risk in tunnels and how this has been used for three existing tunnels, Homer Tunnel, Lyttelton Tunnel and Mt Victoria Tunnel. Key challenges include determining an acceptable safety level, defining realistic inputs, providing sufficient complexity to get meaningful results but not so complex that transparency is lost and interpretation to enable decision-making by non-technical personnel.CITATION:Weaver, S, Wright, B and Ireland, T, 2014. A transparent and pragmatic quantitative risk assessment process for assessing fire safety in New Zealand tunnels, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 121–128 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By J B Tucker, A T. McGrath

Situated in north-west Queensland, Australia, the Ernest Henry Mine (EHM) has been producing copper and gold since 1996. Owned and operated by Glencore Xstrata, ore is currently sourced from a newly developed underground sublevel cave (SLC) mine below the old EHM open pit (the pit). Ore feed to the concentrator is supplemented by satellite open pits comprising the Mount Margaret operation.The transition from open pit to a producing underground mine involved a complex extraction sequence for the first two production sublevels on RL1650 and RL1625. Underground mining during cave initiation was further complicated when south wall instability prevented completion of the final open pit shell. The transition mining phase included mass firing of an inclined crown pillar between the initial SLC void and the pit followed by a combination of transverse and longitudinal SLC mining.The inclined crown pillar mass firing was the first significant milestone in the extraction of the transition ore block. Comprising approximately 890 000 t of in situ material; 70 000 m of drilling was charged with 351 t of emulsion and 6026 electronic detonators to initiate the single mass firing. The firing contained five direction changes over 19 seconds making it one of the largest and most complex underground blasts ever conducted in Australia.Risk management was integrated into every facet of the technical and operational planning and execution of the transition mining phase, whilst maintaining daily mine construction and production commitments. This paper provides a detailed overview of the transition objectives and constraints, mining method selection, post mass blast outcomes and the journey ahead.CITATION:McGrath, A T, Campbell, A D and Tucker, J B, 2014. Transition of the Ernest Henry Mine from open pit to an underground sublevel cave, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 297–308 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

In-pit crushing and conveying (IPCC) is being increasingly considered as an alternative to traditional truck-shovel mining methods. The move towards IPCC is driven by a number of factors including the potential to reduce greenhouse gas emissions, the availability of skilled labour and the need to increase extraction rates to levels that present significant challenges to traditional methods.When considering the relative performance of IPCC and truck-shovel methods, the outcome can be inadvertently impacted by either the use of different simulation approaches, or techniques that do not adequately model the processes in sufficient detail.A simulation approach is proposed that models both IPCC and truck-shovel using the same software platform and is capable of functioning at a wide range of resolutions from life-of-mine scale through to second-by-second asset tracking level. The simulation framework also holds models of processing equipment and hence the mining simulations can be extended to gauge the impact on downstream plant.The approach, known as mine-process operational simulation (MPOS), can be tailored to the level of information available and hence the type of study required, ie order of magnitude, prefeasibility, feasibility, or detailed design.Using information from block models and a range of detailed equipment and process models, MPOS can span major system discontinuities, typified by the mine-plant interface, to allow the estimation of final mine and plant product specifications.

Dec 6, 2010