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By G. J. de Korte

South Africa’s best-quality coal, located in the central Highveld basin, is becoming depleted and alternative sources of coal, such as the Waterberg coalfield, will have to be developed to supply the country with coal in the future. The quality of the coal being mined in the central basin is gradually becoming poorer. This necessitates that more of the coal be processed to improve the quality to meet customer requirements. The challenge to the coal processing industry is to process low-yielding coals to produce goodquality products and at the same time ensure that coal mining remains economically viable. This requires that more cost-effective coal processing technologies be investigated and implemented.

Jan 1, 2015

By Robert H. Merrill

This report contains a summary of the various studies made to determine the structural design of the production mine area of the Oil-Shale mine, Rifle, Colo. Prior to this investigation, it had been determined from a study of the geology, the structure of the deposit, and mining costs that the deposit should be mined by open stoping. The problem remained to determine the maximum safe roof span, the optimum extraction ratio, and the size of the pillars. These factors were determined from a study of the geologic structure of the deposit, the physical properties of the oil shale, and the magnitude and distribution of the stress around proposed underground openings. The latter was determined from both theoretical calculations and model studies. Safe roof spans, pillar sizes, pillar contours, and optimum extraction ratios were calculated from elastic theory and the physical properties of the mine rock. Safe roof spans, pillar sizes; and time effects were determined by Wright and Bucky by testing mine models in a centrifuge. The models were made from rock specimens taken from the proposed mine roof and pillars. The results from both studies agreed.

Jan 1, 1954

By Martin J. Gavin

During the recent study of lubricating oils carried on in the San Francisco laboratory of the United States Bureau of Mines, it became desirable to distill the oils used in the experimental work at pressures as low as 10 millimeters (mercury column) absolute. In the effort to Overcome difficulties and eliminate sources of error, certain changes were made in the apparatus for vacuum distillation used by the Bureau of Mines for crude petroleum.4 These changes were described in R.I. 2819, issued in July, 1927. Subsequent to the publication of R.I. 2819 several other changes have been made, and the present form of the apparatus for vacuum distillation of lubricating oils is described in this revision of R.I. 2819. These changes were found to give more accurate checks on duplicate distillations. The major part of the credit for the laboratory work which developed the changes in the apparatus and method revised herein is due to Boyd Guthrie, assistant petroleum chemist, and R. V. Higgins, junior chemist, o the San Francisco laboratory, United States Bureau of Mines. DESCRIPTION OF APPARATUS The distilling flask employed is essentially the Hempel flask as used by the United States Bureau of Mines for the analytical distillation of petroleum.5 he complete apparatus is shown in Figure 1. The fractionating column and exposed portion of the flask is wrapped with 4 inch asbestos rope and then surrounded by a cylindrical hood of 1/8 inch pliable asbestos sheet with a narrow air space between the wrapping and the cylindrical hood. This was found necessary to prevent any radiation or convection heat losses from the column, and resulted in obtaining a more even and constant fractionation by eliminating any dephlegmating action caused by temperature changes around the column.

Jan 1, 1930

By Sastry Putcha, Vamshi Vemula, Aneesh Goly, Kumar Allady

Current dynamic testing practice to obtain pile total capacity will not yield optimum capacity due to the strain incompatibility between the side and tip resistances during driving. Superposition of end of initial drive- static tip capacity and the peak static skin capacity during beginning of restrike and adding them is the preferred method. The FDOT method determines independent pile static tip and skin capacities in real time analyzing appropriate blows from the embedded tip and top data of the Embedded Data Collectors (EDC). This data is collected through a wireless radio transmitter, receiver, and laptop software. The approach utilizes EDC tip and top data and nonlinear single degree of freedom system to satisfy force and energy equilibrium with a global genetic inversion analysis. Top impacted energy equals at pile tip as sum of Static, Damping and Inertial energy providing independent tip resistance. With EDC sensors as boundary conditions, pile is divided into desired segments and using global inversion techniques one dimensional equation is solved for independent skin friction for every blow. EDC data compared close static load test results. The EDC - FDOT method has enabled cost effective 100% testing of driven piles cost effective. INTRODUCTION Historical documentation has shown that not only driven piles have a long history of usage but also continues to advance unceasingly till today. Historians placed the first pile driving using timber piles in the 4th century BC. While modern pile driving systematically started around nineteenth century, the credit for conceiving the idea of the applicability of wave equation to driven piles goes to David Victor Isaccs of Australia. His 1931publication “Concrete Pile Driving Formulae” provides the basis for modern pile driving using stress wave theory. He felt that the dynamic formulae then in use lacked the capability of detecting integrity and hence developed stress wave theory. This work was further developed starting in 1938 by W.H. Glanville and colleagues of British Building Research Board as they developed the first solution to the wave equation. But these early efforts have really taken off only with the advent of computers. E.A.L. Smith (1960) published ‘Pile Driving Analysis with the Wave Equation’ and provided first numerical solution to the wave equation. Within few years, the FHWA funded research and in due course this effort ushered the era of externally instrumented pile driving.

Jan 1, 2018

By D M. Menne

This paper is intended to give a general review of current gold extraction technology for free-milling or non-refractory auriferous ores. Fundamental process concepts and some of the differences between the current technologies is referred to. Typical flowsheets and layouts are provided and it is demonstrated that technology for extracting free-milling gold is relatively simple. For environmentally sensitive areas such as encountered in New Zealand relevant cyanide decay and destruction technology is also discussed. Brief mention is made of some likely future innovations. Finally reference is made of New Zealand's previous significant contribution to gold extraction technology. These contributions were pioneering ranging from the cyanide leaching of gold to adsorption by carbon and precipitation by zinc. New Zealand has not allowed its potential gold projects to develop at a rate commensurate with the rest of the world thereby stifling its renowned innovative approach in this technology. It is time for New Zealand mining to recognise its unique opportunities in developing gold extraction technology and again take a rightful place in leading the way.

Jan 1, 1986

By V. K. Paruchuri, J. D. Miller, J. Nalaskowski

The phenomenon of surfactant adsorption at mineral surfaces is of significant importance in many particulate processes ranging from mineral flotation and enhanced oil recovery to pharmaceutics, paint technology and the casting of high quality ceramics. Stability of the dispersions is related not only to the amount of adsorbed surfactant but also to the structure of the adsorbed surfactant molecules at the interface. This structure greatly depends on the type of surfactant and the hydrophobicity or hydrophilicity of the surface. On hydrophobic surfaces surfactants adsorb regardless of surface charge by van der Waals/hydrophobic inter-actions with hydrocarbon chains accommodated at the surface. On the other hand, on hydrophilic surfaces the surfactants adsorb through electrostatic interactions with their polar moiety fixed at the surface. In the latter case, the electric charge of the surface and surfactant plays a crucial role in the surfactant adsorption process. The recently developed soft-contact Atomic Force Microscopy technique has revealed images of adsorbed surfactant structures at various interfaces. The adsorbed structures of a cationic surfactant (CTAB) and an anionic surfactant (SDS) are presented in this work for different concentrations at hydrophobic graphite and hydrophilic mica surfaces. Different types of micellar arrangements have been observed at these surfaces for surfactant concentrations around the critical micelle concentration. The structures are more ordered and well defined at the graphite surface than at the mica surface. These results have been correlated with the hydrophobicity of the surfaces as revealed by contact angle measurements.

Jan 1, 2001

By H. A. Doerner

Tellurium is a silver white solid with metallic luster, the e17atal.line torm being ver., brittle aud e.g,s!ly powdered. It has a specific gravity of 6,27, melta at 45a0c. and boils at red het, giving off a. golden 1ellow vapor when air 11 excludei. When heated in air, telluri'UiD burns with a bl\te name tinged with green, and evolves wh1 te vapors ot tellurium dioxide. An amorphous form of tel­lurium, obtained by red.uction and precipi ta.tion from so).ution, haa II specific gr1.vity ot 6,015, and when heated ia cho.nged to the cry:.,talline variety. Telluri,a 11 insoluble in water, c&rbon diaiJ.phido, or h;rd.rochl oric acids, but it 11 41a-1olved bJ nitric or concen t1·ated. sulphi.U·ic acid. It 1..oea not tamiah in moiet ah•• 11 ree11tant to alkaline solutions, e,;:ctpt concentrated KOB, but it 11 cliaaolvecl by tuaed. &lkl 1••. I ts 11.to!!lic weight h..'l.a been the "J.Ubject ot mch controverq, bu\ t.he value 137 .5 :.a bl!ten generally accepted, Tho chflmietr:, of tellurium ia eim1lar to that ot IUlphur. It tonne throo xid.ee TeO, To02, and Te0 , al10 tellur14ea, t•llurite,, and. tellur1.t11, A number of halide compoWld.1, a 3iulph1de, and. a .ulpbat.e are known.

Aug 1, 1922

This report briefly describes the broad program of research and technologic work conducted by the Bureau of Mines on coal and related subjects during 1966. In addition to n description of investigations on mining, preparation, and utilization of coal, an account is given of the Bureau's work in mine health and safety, coal resources, mine explosives, and environmental conditions relating to coal mining and utilization. Details of most of the projects are reported in publications cited throughout this report. Centers and laboratories conducting the coal research and related investigations appear in appendix A; organizations, institutions , and companies contributing to the Bureau's coal research and technologic program are listed in appendix B.

Jan 1, 1967

By W. J. Fene

The lowest number of fatalities from coal-mine explosions in the United States in any year since records have been kept was the total of 8 in 1949 and again in 1950. Even incomplete records as far back as 1870 reveal a larger annual loss of life from explosions. From 1890 to 1948 the lowest annual loss was 32 in 1946. A smaller total of 15 fatalities was reported in 1952. Figure 1 shows the total yearly loss of life from explosions in all coal mines since 1880. Those in anthracite mines alone are shown by the shaded area. The erratic variation of the chart line shows the difficulties that have confronted the industry in the struggle to control and eliminate mine explosions. Potential hazards have existed in marry mines without realization that only a small change in conditions could initiate a disaster. Many disasters causing great loss of life occurred in mines that had been regularly operated without incident for long periods. Although the number of coal-mine explosions causing great lose of life has been kept down in recent years, the exceptions still make the record anything but satis¬factory. There have been almost no widespread explosions for several years, but in a few instances many lives were lost from afterdamp. Although the violence and spread of mine explosions may be controlled, the loss of life may be heavy if many of the men happen to be in the path of the smoke and gases. For these reasons, the strictest controls must be maintained to eliminate all factors that might combine to cause even a small ignition of gas or dust.

Jan 1, 1953

By Russell R. Trengove

Exploring for additional ore bodies on the property of the New Idria Quicksilver Mining Co.'s property at Idria, Calif., was done by the Bureau of Mines in cooperation with the Geological Survey. It comprised a study of the geology, mapping, and searching for additional cinnabar by diamond drilling from both surface and underground. Diamond-drill equipment was moved to the project in November 1941, and drilling was completed in.May 1942. Sixteen holes aggregating 2,580 feet were drilled. Diamond drilling by the Bureau of Mines developed information regarding ore structures that proved valuable to the operators in planning underground prospecting that led directly to the discovery of high-grade ore.

Jan 1, 1949

By Merle L. Bowser

An alinement (steering) sensor for continuous mining machines has been developed under a Bureau of Mines contract. A laser source in the entry projects a beam parallel to the centerline of the entry. The beam is optically shaped to a narrow, vertical fan and illuminates an array of optical sensors bunted on the mini machine. These sensors interpret the location of the beam into meter readings of heading (angle) error and lateral displacement errors. The system, which was tested for 5 months in an operating mine, appears to be fundamentally sound, and with some modification, should be applicable to remote or automatic guidance of continuous miners and other machines.

Jan 1, 1976

By E. J. Babcock, W. W. Odell

The Bureau of Mines since its establishment has always taken an active interest in the utilization of lignite and in the development of the lignite dep'osits of the United States. Extensive lignite fields occur in the west central States, notably in North Dakota, Montana, Wyoming, Colorado, and Texas; there are smaller areas in several other States, some of which are widely separated. The total area of the deposits and the total amount of lignite in these several districts are so enormous that the economic value is seldom recognized. To the people of ·the west and west central regions, however, the larger utilization of lignite, in whatever form it may be, is of fundamental importance, and any new methods or uses that promise to open these great lignite fields for more general and more efficient use deserve careful study. Although these lignite deposits underlie areas of thousands of square miles, their development and general utilization has been rather slow. This is no doubt partly because many of the districts are not thickly settled or highly developed in manufacturing industries, but is largely because lignites, from their peculiar physical and chemical characteristics, are low-grade fuels. Most of the lignites in these areas are imperfectly developed coals; many have a more or less woody structure; some belong to the brown-coal type; and others are darker, denser, and more homogeneous, approaching subbituminous coal. The people living in the regions in which these vast deposits occur, especially in the west central part of the United States, are vitally interested in every effort toward bettering lignite as fuel and aiding its wider utilization.

Jan 1, 1923

By Brian Khalighi, Massimo Franceschi, Giovanni Giacomin, Gianni Porta

Headrace Tunnels and parts of the Access Adit Tunnels of Kárahnjúkar Hydropower project, KAR-14, in Iceland will be excavated using three full-face Robbins Tunnel Boring Machines (TBM). TBM sizes range from 7.23 to 7.63 meters in diameter and the total headrace tunnel length is approximately 40 km. The crushed rock is transported on conveyor belts to disposal areas near each Adit. The estimated average excavation rate is approximately 25 meters per day per machine. Electricity will begin to flow in April 2007, and the project is scheduled for completion in 2009. This paper is divided into four sections. In the PROJECT OVERVIEW section, a short overview of the scope of the project is presented. In the GEOLOGY section, the geological condition along the tunnel drives is briefly introduced. The TBM DESIGN section discusses the various design criteria and the resulting machine specifications. The paper concludes in the TBM OPERATION section with a case history describing the tunneling operation from start-up to the time of the writing of this paper.

Jan 1, 2005

By Jeffrey C. Hillman

The need to recruit locally produced engineers by the South African Mining Industry led to the Engineering Faculty at the University of the Witwatersrand developing a number of academic bridging initiatives for educationally disadvantaged students. The graduation rate achieved during the initial five years of operation by the most successful of these programmes has been on a par with that of al other students but the performance of subsequent intakes has declined to such an extent that the continuance of this scheme could now be at risk. One reason for this reduction in throughput is that many of the applicants for the increasing number of mining bursaries have been more interested in the bursary than the profession and have either failed or dropped out due to a lack of application and motivation. This will have serious consequences for both Wits and the Industry if it continues and some method of identifying unsuitable or suspect applicants needs to be introduced as a mater of urgency. It is recommended that an introductory course be set up at a working mine that would be run under the auspices of Wits, as a joint venture with industry, and include a level of academic input that would provide both bridging needs and certain first year credits. The final form of this course will require extensive consultation with al parties but needs to be completed before the end of 1996. It is further recommended that the advertising and promotion of mining careers be expanded and much improved.

Jan 1, 1996

The 1965 Lignite Symposium, the fourth in a series and the third sponsored by the University of North Dakota and the Bureau of Mines, was held at Bismarck, N. Dak., on April 29-30, 1963. Them 7 symposia provide a forum for those interested in the technology and utilization of solid fuels, especially lignitic coals. As part of the meeting, a 200-mile field trip was taken including inspection of (1) the 200-megawatt, pulverized Lignite-fired Leland Olds plant of Basin Electric Power Cooperative, under construction near Stanton, N. Dak.; (2) the site of the Glenharold mine of the. Truax-Traer Goal Co., Division of Consolidation Coal Co., where a wheel excavator was being assembled; (3) the operating Beulah mine of Knife River Coal Mining Co., subsidiary of Montana-Dakota Utilities Co., near Beulah, N. Dak.; and (4) the 400-megawatt, hydro-electric Garrison Dam powerplant, near Garrison, N. Dak.

Jan 1, 1966

The last issue included a discussion of recent indications of a 1983 recovery and a brief analysis of the contribution of the U.S. mining industry to the gross national product (GNP). In this issue we present sales and other data indicating the strength of the 1983 recovery and quantitatively analyze the structural shifts that have taken place in the U.S. economy and mining industry since 1972, and changes in electricity consumption by the mining industry. U.S. Economic Recovery The tentativeness in the February/March issue of Minerals and Materials regarding the strength and sustainability of the U.S. economic recovery can now be replaced with a note of increased confidence. Real growth of GNP on an annual basis in the first quarter of 1983 was 2.5 percent, compared with 1.4 percent predicted in the Economic Report of the President.1/ Preliminary second-quarter 1983 data provide further cause for optimism. Recently released data indicate that consumer spending is playing a key role in the recovery. Retail sales have increased significantly across a wide array of goods, especially consumer durables, where sales increased 4 percent from March to April (table J) and were 12 percent higher in April [ ] than the 1982 monthly average. Consumer durable sales were led by sales of building materials spurred by the growth in residential construction, motor vehicles and parts, and household durables, including appliances and furniture.

Jan 1, 1983

By L. A. VANFLEET, Allen D. Look

The ever -present danger of mine fires and the possibility of hazardous atmospheric conditions in underground mines make a well-equipped mine rescue station a valuable asset to any mining district . Rescue equipment without proper maintenance provides only false security , because neglect may make the apparatus unfit for use in an emergency . Promptness in fighting mine fires is important ; frequently the first 30 minutes of action are worth many hours later . Likewise , the equipment will be of little value if enough men trained in its use are not readily available . This circular points out how such protection has been provided in an Arizona mining district by establishing a well- organized , adequately equipped , central mine rescue station. ·

Aug 1, 1950

By J. Koster

[In lQ jG thc E'lcct,ro:~(: L7.l :~u..-ic:ll S;%cti ?n of t?c :I. tcIl~tr,-;lcal 3:vi cioa, ?U~CE~U of lv!irtos, bc,~m an 9.ct iv.t In-:?*t ik7;5i GI of r.:ct.l-;c?;is for rccovcrin,; niclrel, cop?ir, an2 ?? cciou:; ~ot-1 c 1;-on or; :; of tile 3unl~crvi~.l~~ tiistrict in C1ni.k Coult:r, !Icl.r. ]

Jan 1, 1939

By Carl Heinrich

I HAVE read with particular interest that portion of the discussion by Anton Eilers referring to the high-lime (and also high-alumina) slags made by August Raht in 1881, while smelting the Horn Silver ores at Franklin, Utah. The two analyses of such slags, furnished by Mr. Raht to Mr. Eilers are: Horn Silver Slags Oxygen(b) Oxygen(b) Average of I and. II Slag I percentage Slag II percentage Oxygen Si02 33.9 18.1 .35.0 18.7 34.50 18.40 FeO 26.8 6.0 25.4 5.7 26.10 5.80 CaO 26.1 7.5 24.9 7.1 25.50 7.30 BaO 3.2 (a) 0.3 3.2 0.3 3.20 0.30 A1203 10.8 5.1 9.3 4.4. 10.05 4.75 100.8 37.0 97.8 36.2

Jan 10, 1916

By F. G. Miller

[Petroleum technoloF;istz and 1 rot-re s s ive OT e:?ztors. con stantl;, are striving to increase the percentage of oil that y to recovered from reservoir rocks throe::;:: wells. The exhaustive studies that have been made of the function of natural r:; as in t h-_ T r odI action of oil, for cx<n.mTnle, have aidedd of.erators greatly in incroasin,&apos; the q-:Arrntity of oil recovered from reservoirs. i.rtural gas dissolv3d in ar--d otinerwwisa &apos;1s&apos;.,ocintjd under rre3suro with oil in roscrvoir roci.s, howover, i:; not the only source of energy available for moving oil through sa&apos;:&apos;l to wells. l becoming "reservoir-energy conscious&apos;t engineers hr-vo -d o^.rued t}:-Lt in many petroleum reservoirs the edgewater flanking t -,e oil accum.-,lation conetitutos a potential source of onergy capable, tL-ou;_h rro? gr control, oil&apos; increasing oil-recovery efficiencies materially. i o ]enter is ti-.-,, on-cronchinunt of water into the oil- and gas--fillod ?art of the reservoir considered as an evil to be combatted by devious mot&apos;:r:ci :i,.t r,ttL er a natural conseque::c4, incident to the withdrawal of oil nna gas from the wells, that nay be T.usod advantrt eou ;ly in lonr`t}toning tr e r&apos;lowin g lift of wells a.nd, i norcas in:; the economic recovery of oil and Little is known about the by which water off: oratos in driving nil throe:gh reservoir roc:-.:,, nd i:. a scorcity of rubli:;Lad informs-¬t .on nn rates of :)Ov.:m.,:- t of : r.tcr ..at v:1:11 res,-_lt in ^r i-nu oil recoveries. Bureau of :fines engine_:? ; - reciate. the r,aucity of scientific knowledge or. the &apos;test methods of a,r.lying the natural water arive to in¬crease oil-recovery efficiencies ant ,i.;?l __-itir?,~ ting irties that will, they hope, Contribute to t.1&apos;.e T ros?Jr.t. small _ %nd of information now av tilable on tt:e cubjoct. This r».crt a oyno-.::is or brief comrilnt.ion of r,ublished data and thought accuinulnt.~d so far, to la)or;~.tory ox-:erimnntrr¬tiorn and, further rosoarch on the z_rrinciplos unri;rlyir..g the natr.rr+1 eater drive no it nffocts oil recovery. :Lie writer:: Lore that t.i.c cx-nositiorn of a?rzilable inforr-at ion i rcs?r.toi in the rernrt r .-II .i ,.1rtt cor_jt_-i:ctive tho.-_.I_t and efforts loadir,-z to -:ard more con.r .ote extraction n;&apos; o tl from reservoirs.]

Jan 1, 1938