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By A. E. Michon

My comments today are directed toward western coal and its impact on Burlington Northern. I will be discussing three major topics. These are: location and extent of mining activities, the flows of this coal traffic into the various market territories, and finally the interaction of this western coal with coals found in the balance of the United States. When we at BN speak of western coal, we refer to those substantial deposits lying in southeastern Montana and north-eastern Wyoming. This territory covers many different coal formations. For the sake of simplicity, I will be referring to this general area as the Powder River Basin (or the "western" coal fields). This slide highlights the area overlayed by a map of the BN rail system. The U.S. Bureau of Mines estimates the demonstrated reserve base of Montana and Wyoming to be approximately 176 billion tons. Of this figure, about 73 billion tons is minable by surface methods. This is roughly 72% of the total strippable reserves in the western united states, BN does not have sole access to this coal for there are deposits in southern Wyoming near the union pacific railroad. I will say more about this later.

Jan 1, 1978

By D. A. Stanley, B. J. Scheiner, P. M. Brown

The Bureau of Mines (USBM), US Department of the Interior, has developed a method of dewatering clay slurries based on flocculation by high-molecular-weight polymers and water removal from the formed flocs using a trommel or hydrosieve. The exchange ion on the clays affects their dewaterability. Metal ions in solution and on the exchange sites of smectite clays are known to act as Lewis acids. Recent work has determined that these ions can be titrated with high-molecular-weight polymers. The relative acidity of the exchange ion and the basicity of the polymer determined by the new method give insight into the dewatering mechanism.

Jan 1, 1990

By G. M. Wilemon, B. J. Scheiner

The Bureau of Mines conducted investigations on extracting phosphate values from fine-particle wastes generated during the mining and beneficiation of phosphate ore by leaching dried wastes using a H2SO4-methanol mixture. Although phosphatic clay waste contains up to a third of the phosphate originally present in the ore, recovery of these values represents a significant challenge due to the fine grain size of the material, the particles averaging less than one micrometer in diameter. Waste samples obtained from two Florida producers yielded phosphate extractions of 71 and 84 pct, respectively, when leached under ambient conditions and at a stoichiometric acid ratio of 1.4:l. Elevated temperatures did not improve the amount of phosphate extracted. Undesirable A12O3, Fe2O3, and PlgO impurities were largely rejected; higher grade wastes gave acids that meet established industry impurity standards and lower grade samples yielded acids that marginally fell short of the standard. Separation of the crude acids from the insoluble residues was accomplished via vacuum filtration through either filter paper or commercial filter cloths. Both filtration rates and solids retention were improved by the addition of 0.5 lb/ton of poly(viny1 acetate) (PVAc) or poly(ethy1ene oxide) (PEO) to the methanol-acid slurries. These results show potential for substantially increasing the reserves of an important domestic resource.

Jan 1, 1989

By O. K. Kuznetzov, L. A. Otrozhdenova, N. D. Malinovskaya, I. I. Maksimov, N. D. Khodov

While processing zinc cakes with application of Weltz-technology silver remains unrecovered and goes into clinker. In order to prevent it the elaboration of effective silver recovery methods from zinc cakes before their weltzing becomes necessary. A combined method of zinc cakes treatment with leaching and flotation in a closed water circuit has been worked out. The technological scheme envisages the use of sulphgydril collectors in combination and comprises a series of consecutive operations: leaching, filtration, precipitation(cementing) and flotation. Total silver recovery is approximately 94%. The technology elaborated has been realized in a project by which the construction of a new shop is under way now.

Jan 1, 1995

By Chris Chmura, Ketut Karmawan, Ian J. Duckworth

P.T. Freeport Indonesia operates a mining complex located in the highlands of West Papua, Indonesia. Present production from PTFI’s DOZ Underground Block Cave Mine is approximately 40 thousand tonnes per day (ktpd). This paper describes the design process and recommended ventilation infrastructure necessary to expand the DOZ Mine reserves and to increase sustained daily production above 50 ktpd. The enlarged footprint will feature longer production panels of up to 650 m in length, more active draw points, a second large gyratory crusher, and additional men and mobile equipment. The increased ventilation capacity will be achieved through the development of new, dedicated ventilation drifts, and primary Underground exhaust fans.

Jan 1, 2005

By A. K. Sinha

Research shows that continuous mining sections can normally produce around 950 tons per shift in a seam 5 or 6 ft. thick. The shuttle cars as well as the continuous haulage systems are able to match with the continuous miners in capacity. However, in practice both of the two systems seem to be averaging at around 450 to 500 tons per shift in production. Continuous haulage systems are preferred in thin seams particularly where the floor is soft.

Jan 1, 1981

By J. Harrison Daniel

Increasing concerns of industrial hygiene and worker health issues and resulting regulatory actions, coupled with continuing advances in mining systems, are placing new burdens on the industry and Federal Government; particularly, mine ventilation departments. More encompassing worker health programs are required to respond to Federal promulgation of regulations and to keep abreast of techno- logical advances in the mining industry. The relationship between the mining industry and Federal agencies involved in rulemaking is presented, along with the rationale of an Industrial Hygiene Management Plan. This plan or strategy focuses on developing partnerships and collaborative research groups to address the controversial health issues facing not only the mining workforce, but our society.

Jan 1, 1993

By M. A. Marticorena, R. Stratton-Crawley, C. I. Basilio

Diethylenetriamine (DETA) is a selective depressant for nickeliferous pyrrhotite during pentlandite flotation. Laboratory flotation tests conducted on ore and process samples showed that pyrrhotite rejection is greatly improved by small additions of DETA; however, the effectiveness of this depressant is most noticeable when the mineral sample is oxidized. LIMS and XPS analyses conducted on flotation products and pyrrhotite specimens showed that the difficulty in pyrrhotite rejection arises from inadvertent activation of the mineral by heavy metal ions, such as Ni2+, cu2+ and Ag+, that are present in the process water. In the presence of DETA, however, the mineral is deactivated under oxidizing conditions. The deactivation mechanism may involve oxidation of the activation products, which are likely in the form of heavy metal sulfides, followed by solubilization by DETA. FTIR spectra of pyrrhotite electrodes contacted with DETA showed no trace of the reagent on the surface, substantiating the view that its role is one of complexing agent that enhances the dissolution of activation products under oxidizing conditions. FTIR spectra of pyrrhotite contacted with amyl xanthate solutions showed that both dixanthogen and iron xanthate are formed on the surface, the latter becoming more predominant at higher potentials. In the presence of DETA, however, only a small amount of xanthate is adsorbed on the mineral at potentials (Eh) approximately 200 mV higher than the case without DETA.

Jan 1, 1995

By D. Nebbia, R. Aliberti, F. Solesin

The launch of a Tunnel Boring Machine (TBM) is one of the most challenging activity parts of the construction of a tunnel. Challenges are coming from limited space available, learning curve, concurrence of other activities and in some cases from the geological conditions. Launching a TBM is an extraordinary and complicated operation requiring a great level of planning. The Earth Pressure Balance (EPB) TBM named “Chris” was successfully launched for the Northeast Boundary Tunnel, the largest component of the Clean Rivers Project in Washington, DC. Due to space and time constraints, the 8-meter diameter TBM was launched from a single 20-meter diameter shaft, with a 30-meter-long tail tunnel by means of umbilical connections. This paper presents the steps followed during the TBM assembly and launching to complete the excavation of the initial drive of the tunnel maintaining high level of efficiency and quality despite the space constraints. Specifically, it focuses on the methods and phases used to extract the excavated material (muck) from the TBM and from the tunnel, to supply consumables, precast rings and backfill grout. The paper presents results in terms of productivity, lesson learned and possible alternatives to be considered in similar conditions.

Jun 13, 2021

By D. S. Kostick

Soda ash production in the United States during 1994 increased 4%, reaching 9.3 Mt (10.2 million st). That was the second highest production year. Domestic nameplate soda ash capacity is about 11 Mt (12 million st). Overall, the industry operated at about 85% of capacity. Some companies produced at 100% of capacity while others produced at below their design ratings. Although domestic soda ash consumption was slow during the first half of the year, third- and fourth-quarter sales increased, especially in the flat¬glass and fiberglass sectors. These two sectors increased because of greater demand for glass products in the automotive and construction industries. Soda ash sold for pulp caustic soda increased during 1994. This was due to higher prices for and reduced availability of electrolytic caustic soda. It is often preferred for pulp digestion because of its stronger alkalinity.

Jan 1, 1995

By J. Fuchs

This paper describes the mechanized narrow vein cut-and-fill approach used for the Deep Copper orebody at Falconbridge Limited's Strathcona Mine. Strategies for achieving high productivity while maintaining ground stability at depth and controlling dilution are discussed, including the use of mini-electrohydraulic drilling equipment, containerized truck haulage, consolidated rockfill placement techniques, and a miners' incentive system.

Jan 1, 1992

By K. L. Wiley

In-situ leaching, initiated in 1986 at San manual, was economically developed in 1989. The primary reason for this lag time between startup and viable production was the time required for technical development. The technical development pursued comprised detailed design, development, and implementation of in-situ well construction methods, formulation of suitable well pattern arrays, and the development of extensive hydrogeologic and geochemical knowledge of the mineral deposit. Since 1989, the in-situ leaching program has become a viable and cost effective method to extract copper from the supergene mineralized zone of the San Manuel deposit. The in-situ leaching methods that are currently utilized have been progressively expanded and continually developed and will became the cornerstone of copper production from the San Manuel oxide mineral deposit. This paper presents an overview of the supergene hydrogeology, current design techniques, drilling methods and well completion, pump determination and setting, solution management, and future plans for the increased extraction of copper by in-situ leaching methods at the San Manuel mine.

Jan 1, 1993

By M. F. Dibble

The Fosfago phosphate rock concentrator is located in the state of Goias, Brazil, 300 km south of Brasilia. The ore is from an enriched carbonatite, which was discovered in 1971 during exploration for pyrochlore niobium ore. The flowsheet was developed in Brazil by personnel from Agrico Chemical Company and Consolidated South America. Engineering was provided by Codemin, a subsidiary of Consolidated, Engineering and construction management was pro- vided by both Agrico and Consolidated personnel who formed the Fosfago team. The concentrator was designed for 500,000 tpy of 37-38% P2Oj dried product. The facilities consist of open pit mining, crushing, stockpiling, and concentration. The product is pipelined seven km to a filtering, flash drying, and railroad loadout station. The plant was successfully started in May 1979.

Jan 1, 1980

By Duluth Engineers' Club, Engineers' Club of Northern Minnesota

"In recent years, much has been said and written on Lake Superior ores, giving the impression that the quality of the ore is deteriorating in grade and that the reserve of high grade ore is rapidly being depleted. Average analyses of ore produced in this district since 1902 show that the average quality has been practically uniform since 1910, and now closely approximates the average for the total reserves of merchantable ore.The accompanying tables and charts show the average analyses for the past ten years, weighted according to tonnage: The chart above shows graphically the average natural iron content for the old range, Mesabi, and grand total Lake Superior ore shipments since 1902.During the last ten years the decrease in iron content for shipments from all ranges except the Menominee was only' .05 of 1 per cent, while for the Menominee ores there was an increase of .052 of 1 per cent. These tabulations and the chart prove that the average quality of the total annual production of iron ore from the Lake Superior district is uniform. Mining men of the district know that all of the merchantable ores of every ore body are being mined out cleanly, and therefore the present average iron ore content of total annual shipments from the district may be expected to continue as long as the present merchantable ore reserves last. There is no logical reason to expect a decrease in the average iron content. Furnaces require ore of definite quality, and if this quality of ore cannot be produced from the natural ore bodies, it must be produced by mechanical means—that is, by concentration of low grade ores or iron formation."

Jan 1, 1920

By J. S. Wozek

In metallurgical applications, coal fulfills dual roles as a chemical feed stock and as a fuel source. These applications range from cokemaking, ironrnaking (including pulverized coal injection), foundry, basic oxygen furnace / electric arc furnace coal additions, direct ironrnaking, Corex, and the futuristic direct steelmaking. In all steelmaking related processes, chemical reactions are simultaneously temperature and chemical dependent. Therefore, coals used in these processes must consistently comply with specific quality parameters in order to promote efficient operations. This paper limits discussion of Metallurgical Coal Quality to cokemaking and ironmaking applications. Its purpose is to present the customer's perspective on the control of critical coal and coke properties.

Jan 1, 1994

By M. Christou

The LIFE-Environment Demonstration Project ?Treating Waste for Restoring Land Sustainability?(www.bangor.ac.uk/ies/TWIRLS/TWIRLS_home.htm), a project initiated by the University of Wales, Bangor, UK in which NAGREF is a partner, aims to demonstrate the effective use of industrial and municipal wastes for the remediation of post-industrial and degraded sites in urban and rural sites. Within the framework of this project, a schist quarry, which is located in a mountainous area near Athens and which has been exploited in the past for cement production, was chosen for bioremediation experiments in collaboration with the quarry owners, TITAN Cement Co. Three different areas within the quarry were selected representing 3 different topographies. These were a compacted, flat area with seasonal water logging (untreated control), a gently sloping, land formed area; and artificially created mounds of overburden rock material formed on the flat area. Compost produced from mixing municipal waste, green waste and digested sewage sludge at the recycling plant of the Association of Communities and Municipalities in the Attica Region (ACMAR), near Athens was used for nutrient amendment. Six replicates of three treatments were applied with varying compost application rates in order to examine the effect of the addition of organic matter in the establishment of suitable vegetation on the infertile schist material. Pine trees (Pinus halepensis Mill.), 4 per replicate, were pocket planted in a volume of 3 liters of schist or schist-compost mixture (1:2 and 2:1). Tree height, main stem diameter and branching were measured following planting and these measurements will be repeated annually to test hypotheses that compaction and water logging reduce Pine establishment by natural regeneration and that nutrient addition improves establishment of pine on schist waste. The availability of nutrients and variation in other soil physico-chemical parameters will also be studied in each treatment and related to plant growth. As a demonstration project, open days are planned on the site for the public and official bodies involved in municipal waste handling and other relevant areas. The aim of these will be to illustrate the effective re-use of waste for the sustainable restoration of post-industrial and degraded land.

Jan 1, 2006

By A. Ang-Ug, L. Gurieff

"The Phu Kham Cu-Au mine in Laos is owned and operated by Phu Bia Mining Limited. The deposit is a complex and low grade Cu-Au porphyry ore. The rougher feed has a particle size distribution of 80% passing 110 µm, and the rougher concentrate is reground for cleaning to 80% passing 25 µm. The Cu losses in the cleaning circuit are primarily in the <12 µm fraction. A randomised paired ON-OFF test of magnetic conditioning in one of the two parallel cleaner 1 circuits was undertaken. The results showed that with magnetic conditioning there was approximately a 10% reduction in the <12 µm Cu distribution in the cleaner 1 tail to a 98% level of confidence. The Cu distribution in the <12µm fraction is a less variable measure of changes in the <12µm Cu recovery, therefore, this was used to evaluate the impact of magnetic conditioning. Subsequently, magnetic conditioning was installed in both cleaner 1 circuits and the plant results monitored after this installation. Comparing the plant results immediately before and after this installation showed that there was a 20% reduction in <12µm Cu losses to the cleaner tail. INTRODUCTION The Cu-Au, Phu Kham Mine (PKM) is located within PanAust's Phu Bia Mining Contract Area in Laos, approximately 140 kilometres from the capital city, Vientiane. PKM is PanAust's flagship operation and the significant cash flow generated by PKM has supported PanAust’s growth, while contributing to a strong balance sheet. PKM comprises an open-pit mine and a conventional milling and flotation operation that produces and exports a Cu and precious metals concentrate. The concentrate contains around 23% Cu, 6 ppm Au and up to 35 ppm silver. Process Overview The PKM deposit consists of complex heterogeneous mineralogy horizons of Cu-Au stockwork and skarn mineralisation. It contains areas of soft-leached zones, overlying transition zones and supergene chalcocite dominant secondary Cu mineralisation and clay-rich gangue. Areas of high As and Zn also pose a challenge in treating the highly variable ore. In addition, hardness of the ore increases with deposit depth. The ROM is hauled to a primary gyratory crusher to produce a coarse ore stockpile with size distribution suitable for the 13 MW semi-autogenous mill. The SAG product feeds two parallel ball mills each equipped with a cyclone cluster producing a product particle size distribution of 80% passing 110 µm. The conventional flotation circuit consists of two parallel rougher banks. The rougher concentrates feed the regrind cyclone where the underflow is split and reports to two parallel, 3MW, M10000 IsaMills. The regrind mill discharge combines with the regrind cyclone overflow with a product particle size distribution 80% passing 25 µm and reports to the Jameson cell."

Jan 1, 2018

By Maurice C. Fuerstenau

INTRODUCTION The term, chelate, from the Greek for &apos;claw,&apos; has its origin in the pincer-like representation of more than one atom of a single ligand bonded to the same metal atom, forming a ring-like structure. Depending on how many attachments exist on the sphere of coordination around the metal ion, ligands are referred to as bidentate, tridentate, tetradentate, pentadentate and hexadentate According to Calvin and Martell (1952) and Somasundaran and Nagaraj (1984), chelating agents must contain suitable functional groups, and their location within the ligand molecule must enable ring formation that is sterically possible. Typical structures that meet these requirements have been given by Fuerstenau and Herrera-Urbina (1988) and are listed in Figure 1. As noted, the functional groups of these reagents contain electron donor atoms such as oxygen, nitrogen and sulfur. Basic groups, such as amino (-NH,), are those that contain an atom with a lone pair of electrons. Acid groups are those, such as carboxylic (-COOH) which lose a hydrogen ion and coordinate with the metal atom. Examples of each of these types chelating reagents are given in Tables 1-4. The specificity of chelating agents for various metal ions has long been known and was utilized early in the search for new flotation collectors. In 1927, Vivian used ammonium nitrosophenylhydroxylamine as a collector for cassiterite. Holman (1929) tested dimethylglyoxime as a collector for nickel oxide. He also suggested taurin as a collector for oxidized lead ores. DeWitt and von Batchelder (1939) suggested the use of oximes as flotation collectors. Gutzeit (1946) conducted an extensive investigation on the use of chelating agents as collectors and as depressants for gangue minerals. The depressants are those reagents that form soluble chelates with metal ions that could function as

Jan 1, 2005

By Zong-Xian Zhang, Charlie C. Li

It has been observed that the rock debris of a strain burst event are often in the mode of tensile fracture. Seismic waves could create tensile fractures in the material nearby reflecting surfaces, such as at the boundary of the fracture zone and the rock surface of an underground space. The fractured rock could be ejected to the space when the seismic waves are powerful enough. The average ejection velocity of the ejected rock is a measure of the magnitude of a burst event. The ejection velocity is directly associated with the released energy from the seismic waves and with the strain energy stored in the rock prior to the burst. In some cases, the seismic wave induced tensile fracture and the energy conversion occur in successive moments during bursting. In this paper, tensile fracture caused by seismic waves is investigated through an 1D model. The relationship of the average ejection velocity of the ejected rock in a rockburst event is analytically established with the energy of the seismic waves and the strain energy stored in the rock.

Apr 26, 2022

By Daniel Tempelis, Tom Freeman, Eric Fordham, John Shamma, Steven Duke

The Arrowhead Tunnels in southern California are being completed by MWD under stringent groundwater in?ow limits established by the U.S. Forest Service. Pre-excavation grouting, new TBMs and a bolted, gasketed, pre-cast concrete segment initial lining are employed to control water in?ows. The effectiveness of prescribed water control measures was analyzed using conservative assumptions with the analytical techniques described by Goodman (1964), Heuer (1995), and numerical modeling. Analyses results suggest groundwater in?ows to the tunnels can be maintained well below the limits with aggressive pre-excavation grouting balanced against a reasonable rate of advance and quality erection of the initial lining system.

Jan 1, 2003