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The principle activities of the Explosives Research Laboratory from July 1, 1961 to June 30, 1962, are described briefly in part 1. Part 2 gives short abstracts of publications that appeared during fiscal year 1962; in general, the research reported in these publications antedates the report period. Part 3 gives the results of an investigation which, although too limited to warrant separate publication, merits presentation in some detail because of current interest in ammonium nitrate-fuel oil compositions.

Jan 1, 1964

By J. W. MacDonald

Two coal mine shafts recently completed in Franklin County, Ill., afford experience and accomplishment to warrant review, These shafts provide access to a tract with a potential recovery of one hundred million tons. This work provided the initial sinking by other than a contractor's organization since 1918. Four additional shafts required during the interim were sunk under contract arrangement with others. Supervisory contact and inspection afforded experience to govern planning and conduct of the recent work.

Jan 1, 1960

By Colin C. West

On August 7, 1986, Barge 45, while being towed near the mouth of the Niagara River, was swept downstream and pinned against one of the central piers of the Peace Bridge. The barge rested against the pier with 125 feet overlying the Canadian border and 50 feet overlying the American border. The tug boat which was towing the barge was lost further downstream. Fortunately, the crew escaped and were rescued with no loss of life. There was serious concern about the potential erosion effects of the river currents on the foundation of the bridge pier as caused by the flow concentrations around the barge structure. Due to the time of year, with the approaching Fall and associated worsening weather conditions, it was imperative that the barge be removed as soon as possible. Donjon Marine of New Jersey, the United States Navy's Atlantic Zone Contractor, was called on to retrieve the barge. By this time the original owner had abandoned the wreck.

Jan 1, 1987

By Rüdiger Wunsch

The new high speed Vienna - St.Pölten line and the Lainzer tunnel are to be connected to the existing Western railway line in Vienna. This involves building an underground cut and cover branching tunnel which will be connected to the Western railway line by ramps. A key structure is the Herzmansky Street tunnel, which has a length of some 820m. It is to be constructed as a cut and cover tunnel using the top down method. The walls of the tunnel are designed as a water resistant structure consisting of double walls, an outer wall of bored piles and an inner reinforced concrete wall. The bored pile wall will be used as a temporary retaining wall during the construction phase and will also be a structural part of the per­manent tunnel wall. The retaining walls of the open pit, which will have a depth of up to 14m and a width of 12m, were investigated as a non-contiguous bored pile wall and overlapped bored pile wall. Preventing ground water from penetrating into the pit is of paramount importance. The high ground wa­ter level is the determining factor for the dimensioning of the bored pile wall and results in the require­ment for a water resistant concrete structure. It has been necessary to adopt adequate measures, therefore, in order to reduce the hydrostatic water pressure during the construction phase, assuming economical pile dimensions.

Jan 1, 2000

By Jaime Tumialán

El presente artículo describe los trabajos subterráneos de la mina Cobriza, la mina más mecanizada del Perú, dado que es la primera en aplicar el minado sin rieles con equipo pesado montado sobre llantas neumáticas u orugas. La mina se encuentra localizada en la Oroya, Huancavelica. Las razones de su mecanización son: crecimiento de los costos, avance de la tecnología, la forma, magnitud y potencia del manto, así como la dureza y resistencia del mineral. Su método de minado es "Corte y Relleno altamente mecanizado con equipo pesado y tiene una productividad en subsuelo de 20Tn/h-g.

Nov 1, 1972

By Priyadharshini M. R., Premalatha K

"Abstract With the development in the construction of heavily loaded structures, the necessity of pile foundations has increased. For the transfer of heavy loads, it is mandatory that the piles need to be socketed in the underlying rock strata. The load transfer in bored rock socketed piles is by end resistance or the combination of shaft and end resistance which in turn depends on the length of the rock socket. The determination of socketing length of the pile at present is mostly based on a few factors which affect the pile load transfer mechanism. The effect of all the possible factors involved, need to be studied in proposing guidelines for the design of rock socketing length of the pile. Analyses are carried out using finite element analysis software (PLAXIS 3D Foundation) to understand the influence of the thickness of overlying strata for different socket lengths of piles in weak rock. From the load settlement curves, the influence of the overlying soil on the rock socket length isobserved and an effective rock socket length is proposed.IntroductionThe determination of socketing length of the pile at present is mostly based on a few factors affecting the pile load transfer mechanism, which sometimes give a better design and sometimes an uneconomical design. Too much socketing length results in more construction time and higher costs. Therefore, the effect of all possible factors involved need to be studied in proposing guidelinesfor the design of t h e r o c k socket length of the pile.The factors that affect the termination criteria of the rock socketed pile are the capacity requirement, thickness and properties of the overlying soil, characteristics of the founding strata, drilling tools used, roughness of the rock socket and nature of loading.A comprehensive study was performed to understand all the above mentioned factors in different types of rocks. In this paper discussion is made on the settlement results, specifically the influence of overlying sand of different densities above a weak rock. The influence of stress developed is not discussed, keeping in mind the size of the paper under study."

Jan 1, 2014

By G. L. Gates

The waters used to waterflood the Wilmington oilfield were studied by the Bureau of Mines, in cooperation with the city of Long Beach, Calif. Increases in the pressure of the injection wells indicated that they were being plugged by materials suspended in the waters. This study was made to identify the suspended materials, determine their origin, and find methods of preventing their formation. The suspended oil-coated materials were iron sulfide, barium sulfate, calcium carbonate, clay, and sand (or silica). Results indicated that the sulfide, which was as high as 90 milligrams per liter, was the product of sulfate-reducing bacteria. The injection of ocean water increased the sulfate content of the waters in the petroleum reservoirs from 3 to 250 milligrams per liter, thereby furnishing sulfate for growth of the bacteria. The waters were supersaturated with barium sulfate. Laboratory tests showed that sulfide could be removed from the waters by adding iron at a cost of 1 to 2 mills per barrel. The solubility of iron sulfide and calcium orthophosphate in the injection waters was also determined.

Jan 1, 1975

By Robert H. Peters

Groundfall accidents have been the leading cause of fatalities in the underground coal mining industry for many years. Statistics from the Mine Safety and Health Administration (MSHA) indicate that approximately half of the victims of these fatal accidents were in an area where no devices had been installed to support the mine's roof. This report was prepared by the U.S. Bureau of Mines to summarize the opinions of 268 coal miners, 29 rust-line supervisors, and 30 MSHA inspectors concerning why people go under unsupported roof, and how to prevent this behavior. Interviews were conducted at six minesites.

Jan 1, 1991

By Anthony D. Barley

Over 60,000 multiple anchors have been used internationally since their introduction in the early 1990s, including 1000 in the United States. The multiple anchor system comprises a "multiple" of "unit" anchors installed within a single borehole - each unit anchor being staggered within the borehole length to mobilize its own capacity independently of the other unit anchors. These systems offer higher capacity than conventional anchors with identical bond lengths due to superior load transfer efficiency. The use of higher capacity anchors may allow reduction in the number of anchors required on a project, which results in time and cost benefits to the anchor installer, contractor, and the owner. Fully removable temporary multiple anchors are available, and have been used with consistent success. Three case histories are discussed highlighting the use of these systems

Jan 1, 2002

By W Farnworth

The Huntly West Mine has undergone significant changes in the last two years, which will affect the remainder of the mine's life. The paper describes the evolvement of plans and an overview of the technical considerations made in planning for and implementing the first New Zealand longwall operation. The technical investigations involve the longwall equipment, exploration, ventilation and strata control. The focus on these areas was to ensure that unacceptable project risks were addressed. Implementation of longwall mining at West Mine is planned in three phases, Development, Panel One extraction trial, and Full Longwall operation.   At present the development phase is complete, longwall installation is in progress and production start-up is planned for the end of August, 1991.

Jan 1, 1991

By Virgil Marple

In the summer of 1979 the University of Minnesota Mobile Laboratory (UMML), designed for the analysis of airborne particles and gases was used to study fugitive dust from an open pit coal mine. The analysis consisted of determining the particle size distribution and concentration of dust from various mining operations, such as blasting, draglines, loading, roadways and bottom scrapers. For some operations the particles size distribution and concentrations were determined at varying distrances. Details of the dust concentration within the plumes as the plume passed the UMML were measured with an optical particle counter. For line sources, such as roadways this enabled the calculation of the particle flux at the sampling location. In addition to the standard instruments associated with the UMML, the applicability of some new instruments were investigated. These included a uniform deposit cascade impactor and a flux meter. Finally, a technique in identifying plume origins which utilized elemental X-ray flourescence analysis of filter samples was shown to be effective.

Jan 1, 1980

By Thomas Novak, Jeffrey L. Kohler, Joseph Sottile, Steve J. Gnapragasam

Modern underground coal mines can be very large, having a total connected load in excess of l5 000 hp. These mines generally have many miles of high-power conveyor belts and 15 or more miles of high-voltage power cables at distribution voltages of 12.47, 13.2, 13.8, or 14.4 kV. The shielded cables used in mine power distribution systems have a significant level of capacitance, on the order of 110 pF/ft. This level of capacitance, in an extensive power distribution system at today's voltage levels, can cause significant charging currents during a ground fault. This paper addresses the potential detrimental effects of capacitance charging currents during line-to-ground faults in mine power distribution systems. A representative mine power system is modeled, and simulations with faults at various locations are conducted to evaluate the effects of this capacitance on the level of fault current and relay selectivity. This paper also includes results of capacitance measurements made on mine power feeder cables used to validate the simulation model.

By H. W. Gillett

UNLIKE most previous Howe lecturers, I had not the good fortune to be associated with Henry Marion Howe, nor to be directly one of his students. Yet, through his writings, he has been my teacher, as he has of all American metallurgists. Instructive as his writings are-I use the present tense because Howe thought so keenly and reasoned so surely, seeing clearly, as if by intuition, what was hazy to lesser minds, that his writings are still vital-it is not, those books and papers, nor even the minds he trained in his classes, that were his most outstanding service. It was the spirit of Howe in his: approach to the problems of metallurgy, his broad-mindedness and fair-ness, his recognition of the need for theories and hypotheses to explain metallurgical phenomena, his willingness to use them as servants, as well as his questioning attitude-his refusal to accept them as masters-that comprise his greatest service. This most thoroughly warrants the honor the Institute pays each year to his memory. These traits I so respect and honor in any man that I glory in this opportunity to do reverence to him in whom they were so notably united.

Jan 1, 1939

By T Graham

The invention of the traditional belt and idler conveyor system is attributed to Thomas Robins in 1892. This basic concept, ubiquitous in most mining operations, has not changed markedly in 125 years and still suffers from five forms of energy losses. Firstly, Wheeler, Roberts and Jones (2004) showed that indentation rolling losses, a consequence of the indentation a roller inflicts on the belt, consume 60 per cent of all energy. Secondly, Wheeler (2006) explained that bulk solid flexure resistance resulting from material interaction and movement absorbs 20 per cent. The remaining energy is lost by idler rotating resistance (5 per cent), belt flexure resistance (5 per cent) and secondary resistances (10 per cent).Traditional conveyor systems are continuous as opposed to batch systems, implying both positive and negative features. On one hand, continuous systems have high availability (available infers ‘ready to run’), but, on the other, utilisation of availability is often low; for example, when a conveyor is running empty or below capacity. This converts into reduced system OEE (overall effective efficiency). Many attempts have been made to mitigate energy losses and low OEE issues, including development of rail-based systems. The key drawbacks have been higher capital cost, low flexibility, poor availability and lack of market acceptance.A recent conceptual development known as the ‘autonomous rail conveyor’ (ARC) promises to address issues of energy loss and poor availability and provide increased flexibility by offering solutions for difficult applications. The ARC uses a series of interconnected skeletal bogies covered with a conventional conveyor belt as a load bed running on relocatable light rail. The bogeys have two axles, each driven by integrated variable speed-geared motor and brake systems, and are connected to previous/next bogeys by specialised couplers. Power is provided by a generator (located in a dedicated bogey) and ‘daisy chain’ plug in cables. Centralised redundant control is provided at a preferred point. Although the system is batch in nature, the number of carriages and trains is flexible, meaning that the system is effectively continuous. Loading is achieved by feeding the ARC from a perpendicularly oriented apron feeder, while material off-loading is accomplished by a twist-dump operation in which the belt is twisted through an angle of 50° below the horizontal, causing material to flow from the belt into a receiving conveyor.The ARC system can run multiple trains over any distance, although benefits are more significant in distances of over two kilometres. Capital and operating costs are predicted to be lower than competitive products, with planned maintenance being simple to perform.CITATION:Graham, T, 2017. The autonomous rail conveyor significantly reduces ore haulage costs, in Proceedings Iron Ore 2017, pp 467–472 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

Seam correlation in the central Rapahoe Sector (Greymouth Coalfield) can be enhanced by detailed lithostratigraphy and chronostratigraphy. Rewanui Coal Measures are overlain comformably by lacustrine, deltaic and fluvial strata, and this upper contact can be located using lithological and geophysical log character. The Cretaceous-Tertiary Boundary (KTB) occurs near the top of Rewanui Coal Measures and has been identified palynologically in 16 drillholes. The Rapahoe Sector can be subdivided into two palynostratigraphic domains which adjoin along a basement normal fault which was downthrown to the north during coal measure deposition. The KTB provides an isochronous surface which is independent of the lithostratigraphic datum. Using the KTB as a datum, the æUpperÆ, æMainÆ and æSubmainÆ seams can be reliably correlated throughout the southern and central Rapahoe Sector. Similarly, the æSubmainÆ seam can be correlated with æcÆ seam of the Strongman Mine area, though other Strongman seams are absent from the central and southern Rapahoe Sector.

Jan 1, 1996

By R. H. Adams, A. M. Khan

The Huntington Beach oil field is on the Pacific Coast, southeast of the City of Los Angeles (Fig. 1). It lies both onshore and offshore. Most of the onshore section is operated by Standard Oil Co. of California, WOI. The Tar reservoir is of upper Pliocene age, about 200 ft thick, and consists principally of fine-grained, unconsolidated, somewhat shaly sand, with thin inter-bedded shale stringers throughout (Fig. 2). The reservoir is a broad, highly faulted, elongated anticline, with an areal extent of about 370 acres. Most of the faults bisecting the structure are normal, trend north-south, and are the main cause of reservoir discontinuity (Figs. 3 and 4). From 1964 to Dec., 1967, 259 steam stimulations were performed on a total of 125 Tar sand wells. Eighty-six new wells were drilled and steam stimulated. Of the total, 96 have been stimulated twice, 34 three times and 3 four times. During this same period, a two-injector steam drive pilot has been in progress. The response obtained from this project has been compared with the response to cyclic stimulation. This paper presents an analysis of the field observations for the two methods of thermal recovery. History of Development Drilling to the Tar pool commenced in 1924 with an initial well production of 40 to 50 B/D of 12o API gravity oil. Complete primary development of the pool has been spread over several years. Approxi- mately 40 wells were drilled during the first phase of development, which was completed in 1945. The subsequent primary development started in 1960 with initial well productions of 30 to 40 B/D oil. Thirty-seven wells were completed in the Tar pool during this phase. For the most part, slotted, gravel flow packed liners have been used in the wells in this pool. A cyclic steam stimulation pilot was initiated in March, 1964. Based on the very successful stimulation in the pilot area, the cyclic stimulation project was expanded to include all of the Tar pool wells producing at the end of 1965 (Fig. 5). Also, a development drilling program was begun at this time. To date, 86 new wells have been drilled under this program. The number of wells drilled each year in this secondary phase of development is also shown in Fig. 5. New Well Completion Practices Most of the new wells have been completed to produce from both the Upper and Lower Tar zones. Generally, a casing stub is cemented from the top of Lower Tar to the base of clean Upper Tar sands to exclude intermediate water-bearing sands. The water string is then cemented from the top of Upper Tar to about 1,500 ft with neat cement and 30 percent silica flour. The annulus from 1,500 ft to surface is then filled with a petroleum-based gel through a high-temperature port collar. Once again, a history of sand-free production dictated the use of 60-mesh gravel flow packed liners. The Upper and Lower Tar

Jan 1, 1970

By Zia Zafir

Design of the deep foundations for the loads imposed by lateral spread include the estimate of the pressure applied by the liquefied material as well as amount of anticipated displacement. In the absence of a non-liquefiable cover over a liquefiable layer, it is possible to design the foundation system just for the additional pressure applied by the flow slides. On the other hand, if a non-liquefiable layer exists above the liquefied zone, the foundation should be designed for anticipated movements. To completely account for liquefaction and/or lateral spread and their interaction with the deep foundation system, a coupled soil-structure interaction (SSI) analysis should be performed. However, a complete SSI analysis may not be feasible for most of the projects. This paper will present recent advances in analysis techniques and simplified methods to design deep foundations for liquefaction and lateral spreading. In addition, a case history of the Rancho California Bridge in southern California located within 1 km of the active Elsinore fault will be presented. One of the bridge abutments is underlain by potentially liquefiable layers. The pressure applied by the liquefiable layer was estimated to be greater than the shear capacity of the 36-inch CIDH piles designed for the abutment. However, with limited ground improvement and more careful analyses incorporating structural effects of CIDH piles, resulting design and construction resulted in a factor of safety greater than 1 against slope failure. The recommended approach was generally consistent with the recently published, and AASHTO sponsored, NCHRP 12-49 project regarding seismic design guidelines for new bridges and the effects of seismic displacements against bridge foundations.

Jan 1, 2006

By Julius Roth

Flyrock is the source of most of the injuries and property damage in a majority of blasting accidents in surface mines. A quantitative correlation between shot conditions and maximum flyrock range can be used to define a "blasting area" in which no personnel or equipment should be present during a shot. The approach used was to develop a model that correlates shot conditions and initial flyrock velocities and permits computation of flyrock range from ballistic trajectories. The Gurney formula for velocity of explosively-propelled plates or fragments was adapted to explosively-propelled flyrock from vertical rock faces or from bench tops. The modified Gurney formula was then "calibrated" with measured flyrock velocities from mining and explosives literature. Charts were then developed for possible field use which give maximum flyrock range as function of shot conditions. The model indicates that for flyrock from vertical faces, borehole diameter, minimum burden and height of explosive column define maximum flyrock range for a given explosive, shot in a given rock. For flyrock originating from bench tops, flyrock range appears to be controlled by the distance of the top of the explosive column to the borehole collar, by total explosive load per borehole and, to a lesser extent, by borehole diameter.

Jan 1, 1979

By M. Hochenhofer

Due to economic aspects and environmental regulations recycling of slag and waste from ferroalloy production became a very important issue for the companies during the last years. The treatment of slag depends prior on the composition, especially on their content of valuable metals and impurities. The final aim should be a total re-use of these materials in the industry e.g. cement industry, pig-iron production etc.. Therefore, to reach the required physical and chemical properties for a further use, possibilities of a metallurgical treatment have been investigated. The conditioning of slag with a high V-, Mo- and P-content via reducing metal bath showed to be one alternative. To determine the optimal process parameters, practical investigations with different slag compositions and thermodynamic calculations were carried out.

Jan 1, 2006

By Harald Ludwig

In 2002, excavation support work commenced on the Capitol Visitor Center project located adjacent to the nation?s Capitol building in Washington, D.C. The outlying work (Slurry Wall Work at Main Site is not discussed) consisted of providing excavation support for a new truck tunnel approximately 1900 feet long up to 50 feet deep as well as support for the new underground auditorium and Library of Congress tunnel. The excavation support consisted of a combination of conventional drilled in soldier beams, lagging, tiebacks and braces; intricate underpinning inside the existing Capitol building; support of an existing Russell Tunnel; soil nailing and tiebacks underneath the existing Russell Tunnel; two temporary bridges; and a deep soil mixed wall with lateral support provided by braces. As part of an on-going research program, some of these braces were instrumented with strain gauges. The deep soil mixed wall was approximately 300 feet long and 65 feet deep on either side of the truck tunnel. Approximately 34,000 sf of deep soil mixed wall, 90,000 sf of conventional excavation support, 200 braces, and 320 tiebacks were installed. This paper describes the large scope and breadth of the project that required a variety of excavation support techniques. A few of the challenges in designing and installing the support of excavation are discussed. This paper also presents the results of the instrumentation program conducted on the deep soil mixed wall, which stood open for more than a year.

Jan 1, 2006