Search Documents

By Lon Santis

This paper analyzes 110 serious accidents that occurred during the use of commercial explosives in mining, construction, and other industries since 1992. Data from the Mine Safety and Health Administration (MSHA), the Institute of Makers of Explosives (IME) members’ reports, and media reports were used. Only accidents that resulted in a fatality, significant lost work time, or injury to the public were considered in this analysis. The accident data were analyzed for trends in frequency, type of industry, cause, type of individual harmed, and geographical region. Although the data showed that explosives accidents are decreasing in frequency, still, 29 people were killed and 134 injured. Eightyfive of the accidents occurred in mining, 17 occurred in construction, and 8 occurred in other industries including oil recovery, seismic exploration, agriculture, logging, boiler cleaning, and avalanche blasting. As other studies have shown, flyrock and failure of blast area security caused over half of the accidents. Mishandling, misfires, or fumes caused just over one-third of the accidents. Lightning and drilling into explosives were responsible for the remainder of accidents.

Jan 1, 2003

By W. S. Hargratt

THE present era of exploitation of the Little Long Lac and Sturgeon River areas commenced in 1925, when Beardmore Gold Mines started development of what is now the property of Northern Empire Mines. A shaft was sunk in 1927-28 and a very limited amount of underground work was carried out, following which the property was shut down. It remained idle until 1932, when Empire Star Mines, a Delaware Company, optioned the property. This Company formed the Northern Empire Mines Company, Limited, to operate the mine, and immediately instigated an aggressive programme of surface and underground development. By the summer of 1933, sufficient ore was indicated to justify the installation of a small mill. The decision was also reached to bring in electric power. A power-line was built from Hydro, the Ontario Power Commission's development on the Nipigon river, to the mine, a distance of approximately 50 miles. This work was entirely financed by Northern Empire Mines. Mill construction was commenced in October, 1933, and completed by March, 1934, thus making this mine the first producer in this district.

Jan 1, 1940

By S. Y. Chen

A new process comprising metallizing reduction, magnetic separation, and electroheat melting separation is proposed with the aim of achieving high recoveries of iron, vanadium, and titanium from vanadium titanomagnetite. The effects of magnetic intensity, reduction temperature, reduction time, carbon ratio, and coal particle size on the efficiency of reductionmagnetic separation were investigated, the reaction mechanisms elucidated by SEM and EDS analysis, and the optimal process parameters established. Recoveries of up to 80.08% for titanium, 95.07% for iron, and 71.60% for vanadium were achieved. The reduction sequence is shown to be: Fe2O3 ? Fe3O4 ? FeO ? Fe; Fe2TiO5 ? Fe2TiO4 + TiO2 ? Fe + FeTiO3 ? Fe + FeTi2O5 ? Fe + TiO2.

Jan 1, 2014

By Ch. Arvanitidis

This work concentrates on investigating the development of a geotechnical classification method for the Greek soils, which can readily provide a rough but usable estimate of the main strength parameters of the soil. It is expected that such a system will be useful to the structural engineer for either checking the laboratory results or for providing a direct estimate in cases where no tests have been conducted. The method provides strength parameter values by relating classification or physical parameters of various types of soils and/or in situ observations of geological and physiographical nature to the strength parameters, such as, cohesion, angle of internal friction, compressibility, modulus of elasticity, etc, by means of a statistical approach and the extraction of empirical formulae.

Jan 1, 2006

By D. Marsh

The feasibility study for the Grasberg Block Cave mine, finalized in May 2008, indicated a production capacity of 160,000 tonnes per day. A rail haulage system was an integral part of the mine design. This paper describes the simulation process used in optimizing the design and discusses the key factors and variables that impact the capacity of the system. The final recommendations for the haulage level layout and associated equipment are also included.

Jan 1, 2010

By H. Suharyono, R. Hogg

A laboratory investigation was performed on flocculation following the addition of polymer to slurries flowing through pipes and in-line (static) mixers. Results are presented showing the effects of flow velocity, pipe length, in-line mixer elements and the use of multiple addition points. Flocculation performance was measured by the settling rate and the supernatant turbidity. The effects of agitation and mixing time are shown to be generally consistent with the results of equivalent tests (both batch and continuous) conducted in stirred tanks.

Jan 1, 1997

By E. J. Gleim

The construction of explosion-proof electric mine equipment for operation in gassy coal mines of the United States was begun as early as 1903. In 1.906, similar equipment with special protective devices was built for export. An investigation of explosion-proof motors was conducted by the United States Bureau of Mines during 1910 and 1911. In other words, this was among the first efforts of the Bureau directed toward the saving of life and property subsequent to its establishment by act of Congress in 1910. In these early motors, those with special devices for relief of explosion pressures predominated. At that time it was generally considered that, by providing for pressure relief, the enclosures could be made lighter in weight because of the lower explosion pressures developed within.

Jan 1, 1954

By William Kent

(Read at the Philadelphia Meeting, February, 1878.) IN the paper by Mr. Fernow, on Red Charcoal, read at the first session of this meeting, it was suggested that this fuel might be used in the blast furnace with greater economy than ordinary or black charcoal. In the discussion which followed the paper, it was stated that the charcoal furnaces of the Lake Superior District have used imperfectly burned charcoal with success, and that these furnaces have given the best results in fuel economy on record. On consulting some of our well-known metallurgical authorities the writer finds that the question of the use of red charcoal, or other imperfectly burned charcoal, or charred wood, is not at all new. In Percy's late work on Fuel, pages 409-414, are given a few facts, which are here condensed, as follows:

Jan 1, 1878

By M. Hagfors

When establishing an underwater testing site for the energy measurements of the explosives, the dimensions of the measuring pool have to be measured to find out what is the maximum weight for the test charge. Secondly one has to decide the distance between the pressure gauge and the shooting point. Thirdly the pool has to be calibrated because of the reflections of the explosions by measuring the bubble periods of the calibration charges. The calibration shots can also be used to estimate the minimum weight of the explosive charge for the reliable energy measurements by calculating the shock, gas heave and total energy values and their standard deviations.

Jan 1, 2007

By John D. Lupton

This paper will discuss the benefits and advantages of using 3D survey data in stope analysis. Obtaining detailed 3D survey data of underground mine progress and production is a challenge. It is almost impossible to ?see? around corners, underneath overhangs, or deep into dark, dusty, humid underground voids. Thus, valuable ore can remain permanently encased in backfill. Without the benefit of 3D survey data, underground mines have the difficult task of meeting grade quotas without the benefit of knowing exactly what has been mined. Lack of this data usually results in unfavorable month end Reconciliation factors, where grades must be adjusted to match grades assessed by the Mill.

Apr 1, 2005

By J. M. Zhuang

Lignosulfonates, by-products of the sulfite pulping process, have been utilized in a process [1, 2] to treat acidic rock drainage (ARD). This process is referred to as the LignorTM process. In the present study, lignosulfonates were found to protect lime from developing an external surface coating, and hence to favor its dissociation. Further, the addition of lignosulfonates to ARD solutions increased the clotting and settling rate of the formed sludge. The capability of lignosulfonates to form stable metal-lignin complexes makes them very useful in retaining metal ions and thus improving the long term stability of the sludge against leaching. The LignorTM process involves metal chelation with lignosulfonates, ARD neutralization by lime to about pH 7, pH adjustment with caustic soda to 9.4 ? 9.6, air oxidation to lower the pH to a desired level, and addition of a minimum amount of FeCl3 for further removal of dissolved metals. The LignorTM process removes all concerned metals (especially Al and Mn) from the ARD of the Britannia Mine (located at Britannia Beach, British Columbia, Canada) to a level lower than the limits of the BC Regulations. Compared with the high density sludge (HDS) process, the LignorTM process has many advantages, such as considerable savings in lime consumption, greatly reduced sludge volume, and improved sludge stability.

Jan 1, 2003

By Ehsan Alavi Gharahbagh

Tool and cutterhead wear is a crucial issue in soft ground tunneling, especially because tool inspection, maintenance, and replacement are done under difficult conditions, and often under pressurized faces or under ?hyperbaric interventions?. Overall, tool inspection and changing is a time consuming and costly step, which needs to be quantified and the related costs accounted for in any construction contract for scheduling and costing of the tunnels at design stage or bid preparation. However, lack of a universally accepted index or measure for soil abrasivity in the geotechnical reports has made it difficult, if not impossible, to define cutter wear for this purpose. Soil abrasion and its impact on cutting tools for tunneling machines under dry or wet conditions have recently been under spot light due to construction claims in several of the recent tunneling projects. The objective of this paper is to examine soil?s physical, mechanical and tribological properties related to the interface of the soil and excavation tools and discuss ways to measure soil abrasivity in a quantitative and repeatable manner. The paper will discuss the efforts that are underway to develop a new soil abrasivity index and the fabrication of a new testing device for this purpose.

Jan 1, 2010

By Jilai Xue

Oxygen gas bubbles generate on anode during Pb electro-deposition process in PbSiF6-H2SiF6 aqueous solutions at room temperature. Cell voltage varies as the bubbles formed on the anodes surface. The bubble layer on the anode makes a voltage drop that consumes energy in the Pb process, which can be reduced by applying ultrasound on the anode. The effects of ultrasound frequency and anodic current density were investigated with ultrasound on and off, alternatively during the Pb electrode-position process. The removing of the gas bubbles were recorded in association with a drop in the cell voltage. The cell voltage can be lowered by 4% - 6% with ultrasound, which has potential for energy saving in Pb production.

Jan 1, 2010

By Loyd R. Kern

A procedure for determining the behavior of a reservoir under a gas or water injection program was reported by Buckley and Levertt in 1942.1 This method, which allowed the calculation of the phase saturation distribution behind the front of a displacing fluid, has been extended to apply to a more general situation. The reservoir may initially contain flowing quantities of the displacing fluid, or the fluid in the reservoir may be above saturation pressure SO that solution effects are present. Production may occur behind the front as in the case of a well which is produced after breakthrough of the displacing fluid. The calculating procedure is simplified in that the graphical integration necessary to determine breakthrough saturation is eliminated by performing a direct integration and the graphical differentiation necessary to determine saturation distribution is eliminated by representing the displacing phase fraction of the flowing stream by an empirical equation. This representation results in simple expressions for the producing gas or water/oil ratio and cumulative production. INTRODUCTION A method for the calculation of the saturation distribution behind the front (interface between the displaced and displacing phases in a gas injection or water flooding operation) was reported by Buckley and Leverett in 1942. The method leads to a curve for the saturation distribution which is double-valued; consequently, part of' the curve was interpreted to be physically meaningless. That part of the curve which has physical significance was determined by a graphical integra-tion (material balance). In this paper it is shown that the integration may be performed analytically with a resulting equation for the saturation of the displacing phase at the front. The case in which the displacing fluid is initially flowing and the case in which the reservoir is initially above the saturation pressure so that some injected gas goes into solution are included in the integration. The calculations are considerably simplified by representing the fraction of the flowing stream which is oil by an exponential function of saturation. The methods is extended to apply approximately to reservoirs in which wells located between the injection well and the front are produced. An illustrative example utilizing the methods presented is included. RESERVOIR BELOW SATURATION PRESSURE In the case of a water flooding operation or in the case of a gas injection operation in which no gas goes into solution in the displaced oil, the equation for saturation in a linear flow system as a function of time and position as given by Buckley and Leverett is where* q = total reservoir volume flow rate, rvb/day A = cross sectional area of system, sq ft / = porosity of formation x = distance from injection point, ft t = time, days Pj = saturation of the displacing phase /dx velocity of planes of constant saturation, ft/day *The nomenclature used here is not the same as that used by Buckley and Leverett A complete nomenclature is given in Appendix A.

Jan 1, 1952

By D. Bouchard, M. Forté, A. Charette

A transparent replica of a casting die was built to achieve a better understanding of the filling mechanisms of aluminum in high pressure die casting. Water and tomato paste were respectively used as analogues for the Newtonian liquid aluminum and the non-Newtonian semi-solid aluminum. The transparent die was installed on an industrial casting press and filling was filmed with a high-speed camera. Differences between the Newtonian and non-Newtonian fluids are presented and discussed.

Jan 1, 2006

By B. J. Scheiner

The Bureau of Mines, U. S. Department of the Interior, is conducting research on a dewatering technique for fine particles generated during the mineral beneficiation process that will recover a portion of the water now being lost using conventional waste disposal methods and significantly reduce the time required for land reclamation. The technique utilizes a flocculant, polyethylene oxide (PEO), that forms strong stable flocs that can be dewatered rapidly on static and/or rotary screens. In field tests, phosphate clay waste has been dewatered from a nominal 2.5 percent solids to greater than 20 percent solids. In other field tests, coal-clay waste has been dewatered from a nominal 3 percent solids to greater than 55 percent solids, in addition, small-scale continuous tests have shown that bentonitic clays can be dewatered from 12 percent solids to 40 percent solids.

Jan 1, 1983

By Mark S. Stagg, Stephen A. Rholl

The firing times of millisecond-delayed initiators are random variables that exhibit varying degrees of scatter. This scatter can cause crowding and overlap of adjacent delay periods, which results in adverse effects on safety, fragmentation, and blasting vibrations.

Jan 1, 1988

By M. Saghaeian, R. Hejazi, L. Hosseini, M. Zare

Difference between plant feed specifications in practice and design feed is a problem that most of processing plants face during operating and commissioning. This topic has led to inappropriate operating and necessitates repeating the basic tests on new feed. Gol-E-Gohar fourth concentrate line with a capacity of 2 MTPY, located in Kerman province, is the first iron concentrate plant in Iran in which High Pressure Grinding Roll (HPGR) technology has been applied. Plant&apos;s feed consists of 30% AG mills pebbles of lines 1-3 and 70% run of mine crushed ore whose Fe=51%, Fe/FeO=2.5, S=1.7% and work index=15 kWh/t. Desired concentrate has Fe>68% and S<0.7%. After the plant construction and operation commencement, providing design feed was not possible due to the crushing unit`s not being complete, therefore the plant was fed by AG mills pebbles. For predicting optimal conditions of the plant and investigating the possibility of improving the current concentrate specifications, sampling from the new feed and laboratory and pilot tests was performed again. Studies showed that new feed has Fe=41%, Fe/FeO=3.5, work index=17 kWh/t. Results of laboratory tests with Davis tube device and pilot tests run using magnetic separators with simulating the plant`s circuit showed that with current feed, achievable recovery in industrial scale would be 75.52% which compared to plant&apos;s recovery in studied period (75.94%) shows that plant operated in optimal conditions. To improve the current concentrate specifications (Fe=66%, S=1.03%, Ferec=75.94%) and for achieving desired concentrate, samples were reground to four fractions with k100= 300, 212, 100, 45 and Davis tube tests were performed on each of the samples separately. Results showed that the fraction whose k100=212 µm or k80=200 µm has respective Fe and S grades of 68.27% and 0.681% which are consistent with the desired concentrate.

Jan 1, 2014

By K. F. Unrug

The research work reported in in this paper deals with the monitoring of roof behavior in a drift mine located in Eastern Kentucky operating in the Coalburg Seam. The thickness of the seam at the monitoring site ranges between 9 and 10 feet with the immediate roof changing from sandstone to shale then back to sandstone. Shale thickness varies between 0 and 2.5 feet. The characteristics of the immediate shaly roof were monitored with 38 dynamometers which were set up in three survey lines to cover the entire range of shale distribution. The dynamometers are capable of providing accurate load readings in the range of +/- 5 pounds. To closely observe the contribution of moisture toward roof deterioration the dynamometers were set up in intake and neutral airways. A television borescoping camera was used in conjunction with the dynamo- metric instrumentations at pre- determined observation holes to physically observe and record the separation process of the shale and sandstone stratum with respect to time. Monitoring took place between January 1985 through January 1986 in order to cover a full cycle of dry and wet mine conditions associated with the seasonal changes. Analysis of the data show a trend of roof deterioration induced by condensation and eventual penetration of moisture within the immediate roof bedding planes, leading to rapid disintegration of the mine roof.

Jan 1, 1986

By T. T. Chen, J. E. Dutrizac

"Grooved cast Pb-Ag anodes are used by some zinc refineries to improve current efficiency. It was found that the manganese oxide scale formed on a grooved Pb-0.75% Ag anode consists mainly of MnO2, which occurs characteristically in rhythmically banded colloform structures and adheres to a layer of ""Pb02+PbS04"" that oxidized from the anode. The relatively homogeneous and nearly fracture-free morphology of the ""Pb02+PbS04"" layer suggests the relatively uniform corrosion of the anode. Deposition of the Mn oxide initially follows the contours of the anode surface, but the grooves eventually become filled with Mn oxide and gypsum. Hydrous Mn oxides and amorphous Mn oxides are believed to be also present in the manganese oxide scale. Tiny particles of PbS04 and SrS04, together with gypsum, other impurities and micro-pores, tend to concentrate in the grooves.IntroductionManganese is a common impurity in hydrometallurgical zinc processing circuits. The manganese originates from sphalerite (Zn,Fe,Mn)S and from the Mn02 added to the leaching circuit to oxidize ferrous ions [1]. Manganese in the sphalerite follows Zn through the roasting, leaching and purification processes, and is present as Mn(II) in the purified ZnS04 solution. The Mn in the added Mn02 is reduced to Mn(II) during the oxidation of the ferrous ions present in the leach solutions. In both cases, MnS04 is generated, and the MnS04 accumulates in the purified solution. In the cellhouse, Zn is plated at the cathodes to produce high quality metal. The Mn(II) is partly oxidized at the anode surface to Mn(IV), and the Mn(IV) precipitates as a scale on the surface of the anode and as a sludge on the bottom of the electrolysis cells. The presence of a thin layer of manganese oxide scale on the surface of the Pb-Ag anode can minimize the corrosion of lead and, accordingly, reduce the contamination of the electrodeposited zinc. However, a heavy manganese scale build-up can cause ""staining"" of the zinc deposits and reduced current efficiencies. Consequently, periodic anode cleaning to remove excess manganese oxide scale is carried out routinely in commercial operations."

Jan 1, 2011