Search Documents

By A Patwardhan, M M. Alam, K K. Thatavar

A commercial wet scrubber was used in the SIU-Joy dust control laboratory to test several concepts for improving the dust control efficiency of a wet scrubber. The concepts tested included two filter-two-spray systems, hollow and full-cone sprays, horizontal and vertical sprays, different layer filters and addition of surfactant. The optimised scrubber configuration had water-only vertical sprays for pre-wetting coarse dust, and vertical surfactant-laden water sprays for wetting ultrafine particles. This scrubber configuration reduced dust concentrations from 250 mg/m3 to 1.8 mg/m3. In comparison, the conventional scrubber configuration in the feed provides an outlet dust concentration of 3 - 4 mg/m3 in field operation. Upon successful testing and optimisation of parameters in the laboratory, field demonstration of the concepts was conducted at an Illinois coal mine. The optimised scrubber configuration was tested in the field with good results in terms of improved visibility in the face area and reduced respirable and quartz dust concentrations. Additional modifications in the field involved relocation of the scrubber suction inlets from the bottom to the side and changing the water spray configuration on the miner head. These additional changes were based on a conceptualised spatial dust distribution profile in the face area. The results of these laboratory development and field demonstration studies are presented in this paper.

Jan 1, 2005

By J. P. Hansen

The Bureau of Mines has investigated the S02 leaching of MgO from high-MgO-bearing Florida phosphate concentrates. The S02 was effective in leaching some of the MgO from three phosphate concentrates; flow rate of the S02 and leach time were major factors in determining the amount of MgO leached. Calcining the samples, then grinding to minus 200 mesh, and elevating the leach temperature gave only small increases in the amount of MgO leached. The research also showed that some of the MgO was so intimately associated with the phosphate mineral that it could not be removed by S02 leaching. This amounted to about 0.6, 0.7, and 1.0 pct MgO in three leached residues. The calculated heads for the three concentrate samples averaged 1.4, 1.1, and 1.5 pct MgO, respectively, before leaching.

Jan 1, 1985

By R. R. Klimpel

The process of flotation is an extremely important solids separation technique employed in a wide variety of industrial process applications. Froth flotation is practiced in the coal industry to recover fines produced during the mining and cleaning of coal. A recent review article by Aplan (1) covers the processing variables encountered in the flotation of coal and the variety of chemicals and operating conditions which affect recovery. Numerous engineering and scientific studies have been performed with the goal of providing semifundamental laws of flotation behavior for improved screening of flotation chemicals, better equipment scale-up factors, etc. Often the results of such work are expressed in the form of mathematical models (e.g. 2, 3, 4, 5, 6) which are potentially useful for evaluating (simulating) on paper such alternatives as possibles process operating or configuration changes, the effects of ore and reagent changes, etc. It appears to be commonly accepted that a complete scientific/engineering characterization of flotation is immensely complicated and not sufficiently developed at the present to accurately predict (or understand) many important industrial facets of flotation. Thus, one is often reduced to detailed experimental characterization in both the laboratory and plant in order to fully evaluate flotation changes or alternatives. It is the purpose of this paper to describe a method of batch laboratory data characterization that is useful in evaluating flotation chemical reagents including froth flotation of coal. The approach consists of running a series of time-recovery curves in a batch float cell followed by the computer curve fitting of this data to a series of mathematical models based on semi-physical reasoning. The unknowns or parameters of these models are then optimally chosen so as to best fit the experimental data. It has been found in both coal and mineral systems that changes in reagent type, concentration, system pH, grind, etc. cause very consistent and logical changes to

Jan 1, 1979

By Maria Flessas, Justin Ray, Danielle Steinmetz, Brian Zuckerman

"The Ventura County Medical Center Hospital Replacement Wing project consists of the construction of a 2- to 3-story building with a basement encompassing the entire footprint and two corridors connecting the new hospital wing to existing buildings. The site is located in the Ventura Basin where strong ground shaking has been observed during moderate to large earthquakes on nearby faults. The upper 90 feet of the soil consists of loose to medium dense finegrained sands and low plasticity silts that are potentially susceptible to liquefaction, seismic densification, and hydroconsolidation. Ground settlement associated with a large seismic event on a nearby fault is estimated at 20 to 26 inches. To account for the anticipated ground settlement, auger pressure grouted (APG) piles gaining support below the potentially liquefiable soil were selected for the support of the proposed structure. Challenges for pile design included the anticipated earthquake-induced ground settlement, high downdrag loads, low soil lateral capacity during strong ground shaking, and the effect of pile installation on the performance of the existing adjacent buildings and the installed shoring system. The replacement hospital is supported on over 600 APG piles, with lengths varying between 120 and 140 feet. Axial pile capacities were verified with an extensive indicator pile installation program and dynamic pile load testing.INTRODUCTIONThe Hospital Replacement Wing (HRW) project is at the Ventura County Medical Center (VCMC) in Ventura County, Southern California (Figure 1). The VCMC consists of three interconnected hospital buildings (Buildings 303, 304, and Fainer Building), the Medical Laboratory/Cafeteria Building, two mental health buildings, a medical office building, an emergency generator building, and surface parking lots. The HRW is near the center of the campus, adjacent to several existing buildings.The HRW is a 2- to 3-story structure, with a 15- to 20-foot-deep basement beneath the entire 95,000-square-foot building footprint. The HRW project includes a Loading Dock, a four-level corridor to the Fainer Building (Fainer connector), and a two-level corridor to the Medical Laboratory/Cafeteria Building (Café connector). The corridors are structurally separated from the existing buildings. Typical dead plus live load column loads for the HRW range from about 635 kips to 935 kips and total loads range from about 860 kips to 1,295 kips."

Jan 1, 2016

By J. W. Reynolds

Use of crushed waste rock recovered by sink-float separation from normal ore production for backfill is an established procedure at Commco's Sulhvan mme, Kimberley, British Columbia. Need for a safe method of placement in voids which were difficult to reach by gravity methods led to a co-operative venture with Radmark Engineering Ltd. in the development of a workable pneumatic transportation system for rock material. This paper reviews work done to date in a current program, and includes comments on the nature of the fill so placed, options for cementing such fill, implications for other aspects of mining and references to other applications of the system by other organizations who exchanged experiences with the Sullivan mine staff during the five-year period reviewed.

Jan 1, 1972

By Roberto Pimentel de Souza

Since 1976 CVRD is carrying out tests to develop a type of pellet made with organic binder. One binder that showed good possibility to be used in industrial plants is Peridur. An extensive framework of tests was run in CVRD's pilot plant. The results are presented in this paper. Finally, the decision was taken to carry out an industrial production of 50.000 t of pellets. It was scheduled for March '81. The results are shown in this pager. It was not observed any detrimental effect of the peridur neither in the process nor in the product quality.

Jan 1, 1981

By K. Y. Haramy

A scale-invariant theory of the strength and deformability of rock masses in static equilibrium and at incipient failure is proposed. The theory provides a rationale for designing structures in rock. This paper presents results of experiments conducted by the U.S. Bureau of Mines and theoretical methods to determine and interpret in situ strength of rock masses using the borehole shear tester.

Jan 1, 1995

By FRABK HERVEY PETTINGELL

THE stock exchange and its functions is about as well understood by the average individual as the fourth dimension. What is a stock exchange? Divested of the rules and regulations by which it is governed, and the facilities it provides for the convenient handling of securities, it would be in its nude state nothing more or less than a meeting place for brokers. The stock exchange in America dates back to 1752, when a group of merchants of New York established a meeting place at the foot of Broad Street for the purpose of dealing in meal and slaves. The first definite orgarization, however, had its beginning in 1792 when 24 New York brokers signed an agreement not to buy or sell public stock for less than one quarter per cent. commission. From this small group has grown by gradual degrees, the greatest organized security market in the world, namely, the New York Stock Exchange. At the present time there are 27 stock exchanges in the United States and 5 in Canada. Based on the volume of business transacted, the Los Angeles Stock Exchange ranks 6th among them. This is attributable to the fact that strictly speaking Los Angeles has never been a stock exchange town, like some other large cities. Take for instance San Francisco, which supported one stock exchange from 1862 to .1882 and has since supported two. No city, by the way, should tolerate two stock exchanges at the same time. It is an economic folly and a senseless duplication that can be compared with rival telephone companies or competing street railway systems, paralleling each other's lines and always leads to trouble and confusion, and sooner or later one or the other falls by the wayside. While Los Angeles has had stock exchanges of one kind or another since 1896, none of them attracted much attention until 1899 when the present exchange was organized and it did not get well under way until along in 1906.

Jan 1, 1925

By Arthur F. TQggQrt

THE approximate status of education in ore dressing in 1871 is reflected by Rossiter W. Raymond in an article written at that time presenting the curricula and descriptions of the laboratories at the various mining schools in the United States. For the most part, the curricula in which ore dressing was taught were for mining engineering. They comprised courses in geology, mining, and pyrometallurgy about equal in point or credit weights; a short course in ore dressing, and a somewhat longer course in assaying; and courses in surveying, hydraulics, power, and strength of materials-all superimposed on a broad foundation of physics, chemistry, and mathematics. Some curricula contained a fair content of the humanities. Then, as now, the emphasis on fundamentals was greater in the older colleges and universities. The report on the Columbia School of Mines, then relatively young, emphasized that a large percentage of its students were college graduates. As technical and scientific knowledge grew, first metallurgy and then geology were set up as separate curricula. So far as curriculum designation is con-

Jan 1, 1947

By H. Kenworthy, M. M. Fine

The progress made to date in the mineral dressing of complex Arkansas titanium ores is reported in this paper. Concentrates of rutile, a dioxide of titanium, were produced by treating a submarginal ore from the Magnet Cove Rutile Co., Inc., Magnet, Ark. The rutile recovery at present is 45 to 50 pct of the total TiO2 with the possibility of increased recovery with additional research. The work reported herein is part of a general study which will later include results of investigation of other titanium ore bodies in the Magnet, Ark., area. The fragile character of the rutile minerals, the softness of the gangue, the occurrence of pyrite and leucoxene, and the considerable proportion of extremely small size rutile in the presence of montmorillonite- and illite- type clays in the Magnet Cove open-pit mine are the important factors in the mineral dressing of this submarginal rutile ore.

Jan 1, 1949

By L. S. Cates

THE war is now behind us. We in the mining industry feel a just pride in the part that our industry and our men and our products played in defeating the enemy on the fighting fronts around the world. In five years of mobilization and actual combat, our mines and oil wells produced over 3 billion tons of coal, a billion tons of petroleum, 500 million tons of iron ore, 21/4 million tons of lead, 31/2 million tons of zinc, 5 million tons of copper, 14 million tons of bauxite, 17 million tons of sulphur, 68 million tons of salt, and 3 million tons of potash. It was an unparalleled performance. But what of today? Why the present low production and high costs? Among the black clouds in the mining sky none are so black as that presented by the labor situation. We know it is the result of the legislation and the interpretation of that legislation in the past ten or fifteen years. Since the passage of the Norris-LaGuardia Act in 1932, we have had nothing but a succession of laws, regulations, and decisions that have intensified the strength of the unions and made the operators of the mines and the sources of their financing prartirally impotent

Jan 1, 1946

By Hans Lundberg

AFTER the war years, great activity has been shown in geophysical exploration for ore. The appreciation by mining and government geologists of geophysical techniques and results is largely responsible for the popularity of these methods. In Canada, plans are being made to study, by geophysical methods, the structure of a portion of the Pre-Cambrian shield in the hope that such studies will not only give a clearer picture of the geology, but will be of direct aid to the mining companies when selecting areas for detailed prospecting. Although geophysics thus has become more popular, some engineers are still reluctant to employ the methods to their full extent. Allotted funds are often rather low, so that the least expensive

Jan 1, 1947

By Behrooz Abbasi, Seyedsaeid Ahmadvand, Thom Seal, Babak Azarfar, Bryan Ulrich

Hydro-Jex® is a new enhanced method for heap leach treatment with significantly higher mineral recovery. In this case study at the Los Filos Mine in Mexico, the Hydro-Jex operation is evaluated for heap leach stability. This is pursued by numerical modeling of the heap leach pad stability and well monitoring of the phreatic surface before and after the Hydro-Jex operation. Experimental and numerical results both indicate an improvement in mineral processing under the influence of Hydro-Jex. Numerical results show an insignificant decrease and a significant increase in stability during and after Hydro-Jex injection application, respectively. The integrity of the liner is maintained in both cases. The zonal injection pressure, operationally below the overburden pressure, is found to be negligible compared with the dimensionality of the heap, and stability of the structure is not exposed to any significant risk, even up to 25%above overburden pressure. Furthermore, heap leach factor of safety increases after Hydro-Jex application. This is attributed to breakdown of the water solution build-up and thus a decrease in the phreatic surface depth below the top of the pad. It is suggested that injection wells be drilled, based on thorough geophysical data, in locations where overcompaction of heap material results in water solution build-up and pore pressure enhancement. Compared with traditional heap leaching, the Hydro-Jex technique not only expedites mineral processing by increasing chemical kinetics extraction but also increases the stability of the heap by unclogging drains.

Jun 29, 2020

By John V. Beall

Let's start at the beginning, Mr. Turner. Where and when were you born? In Lansing, Mich., on July 31, 1880. And what was your education? I went to the University of Michigan, where I got an A.B. degree in 1902; then to the Michigan College of Mines at Houghton, graduating from there in 1904 with a B.S. and an E.M. What was your first job in the mining industry, Mr. Turner, and what were you paid? In the summer of 1902, 1 was a field assistant for the U. S. Geological Survey in southwestern Idaho and southeastern Oregon, working under Israel C. Russell, professor of geology at the University of Michigan, who incidentally, had just returned from an expedition to study the effects of the eruption of Mt. Pelee, on Martinique. I was paid $60 a month and found; in addition to doing geologic and hydrographic work, I cooked many of the meals for a party of four, and wrangled four horses. I slept for four months under the stars, without a tent.

Jan 1, 1949

By Jonathan D. Aubertin

The unique nature of rock salt blasting is compared to traditional hard rock practices. Rock salt geomechanical nature is discussed in the context of rock blasting events. A cratering mechanism prevalent in soft rocks is presented and exemplified through a series of single hole blast tests performed in salt deposits.

Feb 1, 2020

By Susan M. Moore

The objective of this study was to evaluate the circumstances leading to fall from equipment injuries in the mining industry. Method: The 2006 and 2007 Mine Safety and Health Administration annual injury databases were utilized for this study whereby the injury narrative, nature of injury, body part injured, mine type, age at injury, and days lost were evaluated for each injury. Results: The majority of injuries occurred at surface mining facilities (~60%) with fractures and sprains/strains being the most common injuries occurring to the major joints of the body. Nearly 50% of injuries occurred during ingress/egress, predominately during egress, and approximately 25% of injuries occurred during maintenance tasks. The majority of injuries occurred in relation to large trucks, wheel loaders, dozers, and conveyors/belts. The severity of injury was independent of age and the median days lost was seven days; however, there was a large range in severity. Impact on industry: From the data obtained in this study, several different research areas have been identified for future work, which include balance and stability control when descending ladders and equipment design for maintenance tasks.

Jan 1, 2009

By The Hollinger Mill Staff

MR. E. L. Longmore (l), in presenting this paper at the Annual General Meeting, suggested that it was neither desirable nor necessary to read any but the briefest portion of the paper. He wished to emphasize that the scale of the milling operations at the Hollinger not only provided several units in continuous operation to ensure that the test work was being carried on under normal conditions, but also provided a large and competent staff to supervise such an extensive experiment and to criticize intelligently the recorded results. He wished to acknowledge the enthusiastic co-operation of the group of assistants whose excellent work was responsible for the confidence with which the conclusions could be presented. The following data were given as a supplement to the published paper. Following conclusion of the test work described in the paper, the size of the balls fed to the mill was changed from 3-in. diameter to 2Yz-in. Within a short time, a gradual rise in the tonnage rate took place and, as no other condition had been changed, the increased tonnage was credited to the changed character of the ball load. At present, the average daily tonnage for the mill with low discharge is 1,507 tons, an increase of 77 tons over the 1,430 tons ground when feeding a 3-in. ball. A similar increase in tonnage should be credited to the high-discharge test, if the 2;Y2-in. ball had been used at that time. This would raise the 1,117 tons ground at that time to a new figure of 1,177 tons. From a study made to determine those factors influencing the rate of pulp flow through the low-discharge mill, it became evident that the ball screen used on the high-discharge mill must have been restricting the flow through the mill, although this was not recognized at the time. Accord-ingly, it was decided to repeat the high-discharge run. Additional length was added to the 21-in. ring grizzly originally used, and the length of the reverse spiral was increased. The end of the grizzly was left open so that, if necessary, excess pulp might flow out. A coarse mesh 3 ft. by 3 ft. flat screen was provided to catch stray balls.

Jan 1, 1937

By Chengcan Wang, Jin-Tae Han, Young-Eun Jang

"The waveform micropile is a newly developed foundation type for increasing the bearing capacity with the created shear keys on the pile’s shaft. Analyzing the increment of resistance at the shear key zone is a crucial factor in the design of the waveform micropile. Hence, centrifuge tests were carried out employing six different models, including a waveform micropile in the axial loading condition. The analysis results of the load-settlement curves showed that the waveform micropile achieved a higher bearing capacity compared to the micropile without shear keys. In addition, the test results revealed that the load-settlement relationship was affected not only by the pile shape but also by the locations of the shear keysINTRODUCTIONA micropile is a small-diameter pile, typically constructed with a less than 300 mm diameter. Generally, the micropile’s construction involves drilling, grouting, and insertion of a reinforcement material, such as a thread bar. The micopile can be utilized in a variety of fields for reinforcing the foundations of existing structures. It also has advantages for accessing challenging areas like limited-access construction sites, including those with a low headroom space and adjacent structures, due to the small size of the construction equipment. Thus, since it was introduced in 1950 in Italy, the micropile has become one of the preferred solutions when other deep-foundation methods are not applicable to the site.Federal Highway Administration (FHWA) gives the micropile design implementation guideline of neglecting the end bearing due to its small diameter but considering the frictional resistance if the bond zone of the pile is in the soil or on a weak rock. The bearing capacity is considered primarily only if the micropile is founded on a high-quality sound rock (FHWA, 2005). Micropile design in South Korea is currently being performed based on the FHWA manual and taking into consideration the frictional resistance for the design as the pile generally sockets into a weak rock or soft rock. Moreover, the frictional resistance within the soil layer has usually been ignored, considering only the shaft resistance of the rocksocketed length in the conservative design. The design concept excluding the frictional resistance in the soil layer, however, may lead to an extension of the pile socket length, which will increase the construction cost. Hence, many researches have attempted to provide better design and construction methods to increase the bearing capacity in a cost-effective way (Juran et al. 2001; Sadek and Isam 2004; Tsukada et al. 2006; Finno 2002; Gomez et al. 2003; Seo et al. 2013)."

Jan 1, 2016

By Chu E. Ho, Paul Napoli

A new waterfront park was developed on Long Island in close proximity to the East River and Newtown Creek. The existing ground consisted of fill over soft organic clay, medium dense silty sand, glacial till and schist bedrock. The ground was initially raised to preload the underlying soft soils to stabilize the ground in preparation for site development. The ground was subsequently cut down to temporary grades for installation of foundation piles for the overlook structures and construction of reinforced concrete cantilever retaining walls forming pathways located adjacent to the water bodies. The retaining walls were located in two rows at different elevations along the sides of a steep embankment. Where the pathways converge, some of the walls were too close to each other, and were redesigned as a combined U-wall with a common base slab. The individual retaining walls were designed for adequate bearing, sliding and overturning resistance. Ground anchors were installed to enhance global stability of the retaining walls. This paper presents the design considerations for the retaining walls for various loading conditions, and evaluation of the trial and proof tests for the anchors. INTRODUCTION The New York City Master Plan included the transformation of an approximately 30-acre parcel of land in Long Island City, Queens, New York from a former manufacturing zone into a residential, commercial and recreational zone for middle-income community. The site was located at Hunters Point South along the eastern shoreline of the East River and Newtown Creek (Figure 1). The development included low to high- rise residential buildings, a public school, and retail structures. Open spaces were provided along the East River and Newtown Creek waterfronts in the form of a continuous park providing for recreational and community-related activities. Waterfront structures included small park buildings, walkways and viewing platforms. The shoreline was surrounded by revetments as part of the flood mitigation strategy. The project involved extensive site re-grading and several retaining walls were constructed. The earthwork volume amounted to approximately 47,000 cubic yard of imported fill and 93,000 cubic yard of cut. The exposed height of the retaining walls ranged from 3 to 15 feet. This paper focuses on the design and construction of the retaining walls for the project.

Jan 1, 2019

By Larry G. Twidwell

The removal of dissolved arsenic from mine waste waters utilizing a lime/phosphate precipitation technique has been studied on a laboratory scale at Montana Tech of The University of Montana and on a pilot scale at MSE Technology Applications as a wastewater treatment process potentially capable of removing dissolved arsenic to <50 µg/L. Arsenic bearing lime and lime/phosphate slurries were subjected to laboratory extended-time air-sparged aging for over four years. The lime slurries released their arsenic back into solution in a relatively short period of time, whereas the lime/phosphate slurries showed limited release of arsenic. The developed process has been pilot scale tested by MSE-TA for the EPA Mine Waste Technology Program on three waters, ASARCO smelter blowdown water, ASARCO thickener overflow water, and Mineral Hill Mine groundwater. The laboratory study results will be presented and discussed in this presentation. The pilot scale results will be presented and discussed in a companion presentation. Stability, Aging, Apatite, Johnbaumite

Jan 1, 2005