Search Documents

A great range of contacting equipment is used in solvent extraction. However, a tower filled with a regular packing offers many advantages in the direct extraction from slurries. A study was made of the flow of a dense slurry through a packed tower in which the continuous phase was kerosene. The grid type packing, which was preferentially wetted by the slurry, had slats inclined at an angle of 30¦, to the horizontal. On the sur- face of the slats there were uniformly spaced longitudinal indentat- ions. These were of a height slightly less than the film thickness and divided the slurry discharging from the bottom of the slats into a number of uniform streams. When slurry entered the tower it was distributed by means of a troughs and weirs type of distributor. Because of the relatively high slurry velocities that occur at the entry region, it was necess- ary to have the distributor and the first two grids above the solvent level. The interface at the bottom of the tower was located at the mid-point of the bottom grid, so that the slurry entered the interface as a continuous film across the full width of the slats. Using the above system, stable flow with low entrainment was achieved at slurry flow rates of 3.4 mis/cm/sec. This would be equivalent to a flow rate of 177 gallons per minute through a tower of cross-section 4 ft 4 in. by 4 ft 10 in., or 1200 tons per day of solids of specific gravity 2.6 when the pulp density was 65 per cent. Previous tests indicated that a total tower height of about 30 ft would be required for a recovery of better than 99 per cent.

Jan 1, 1969

By William Gleason

"Sluggish prices for commodities and a glut of oversupply of many commodities did not stop the world’s largest mining equipment makers from showing off their latest and greatest machines and technology starting with the world’s largest equipment trade show, bauma 2016 in Munich, Germany.From April 8-14, an estimated 580,000 visitors from 200 countries visited the show that featured 3,423 exhibitors from 58 countries. While primarily a show for construction equipment, the mining footprint has grown over the years. Among the largest exhibits was that of Liebherr, which brought more than 100 products, had an outdoor exhibition stand, a stand for the components division and a career stand under the motto “Be Part of Something Bigger.” One of the biggest aspects of the exhibit was its mining products where the company staged the first-ever professional table tennis match in the 130 m3 (170 cu yd) dump body of the T 264 mining truck. The top German players Timo Boll and Patrick Franziska with their trainer Jörg Robkopf faced Austria’s singles world champion from 2003, Werner Schlager, and the reigning Team Europe champions Chen Weixing and Stefan Fegerl.“Bauma 2016 was an absolute success for Liebherr. With this year’s appearance we were once again able to show our innovative strength, performance and technological diversity to a very large and international audience from the industry. We conducted interesting discussions with numerous customers and partners from various countries and discussed new projects,” said Stefan Heissler, Member of the board of directors of the Liebherr Group.Likewise, Caterpillar, the world’s largest maker of construction and mining equipment had a large presence at the show with more than 60 products and 12,000 m2 (129,000 sq ft)of exhibit space. Among the iconic yellow mining equipment that was on display was the 6015B hydraulic mining shovel."

Jun 1, 2016

By Michael J. Jorgensen, Pranathi B. Aedla, N. K. Kittusamy

Risk factors associated with the development of muscu­loskeletal discomfort and disorders during the operation of heavy mobile equipment include whole-body vibration and awkward and sustained joint postures of the shoulders, neck, and trunk. Cab design may influence awkward postures of the joints, and task duration may influence duration of exposure to awkward and static postures and whole-body vibration. To reduce exposure to risk factors related to the interface between cab design and task, it may be necessary for manufacturers to address cab design. This study assessed the repeatability of a cab design checklist developed to evaluate various design characteristics that can influence exposure to risk factors for musculoskeletal discomfort. The ability of the cab design checklist to identify posture-related deficiencies of design was also assessed. The checklist was used by two administrators across 10 pieces of heavy construction equipment. Video analysis was performed to quantify postures of the neck, shoulder, and trunk; correlation analysis was used to determine whether specific questions from the checklist were associated with the identification of awkward postures. The repeatability assessment resulted in kappa coefficients ranging from 0.52 to 1.0 (good-to-excellent reproducibility) across each piece of equipment, and an overall kappa coefficient of 0.77 (excellent reproducibility) when considering all equipment together. Results from the correlation analysis showed that shoulder flexion posture was correlated with scores from the cab design checklist. However, results of the cab design checklist were not significantly correlated with shoulder abduction or awkward postures of the neck and trunk. Results suggest that the cab design checklist may be useful for identifying cab design characteristics that need further improvement and for identifying design characteristics that increase shoulder flexion. The strength of the repeatability assessment suggests that outcomes of the cab design checklist administered by different individuals may be consistent, independent of the type of equipment being assessed.

By Sidney Katell

This report is the fourth in the series, Bibliography of Investment and Operating Costs for Chemical and Petroleum Plants. The initial work, Bureau of Mines In- formation Circular 7516, was published in October 1949 in conjunction with the synthetic liquid fuels program authorized by Public Law 290, 78th Congress. It included references to and abstracts of publications appearing from 1930 to September 1948 on all processes in general use in the petroleum refining and chemical industries. A supplemental bibliography, Bureau of Mines Information Circular 7705, was published in January 1955 to cover the period September 1948 through June 1952; and Supplement 2, Information Circular 7751, published in September 1956, covered the period June 1952 through June 1954. The present supplement covers the period July 1954 through December 1956.21 The information in this paper was obtained from the following sources: 1. Bureau of Mines Information Circulars. 2. Bureau of Mines Reports of Investigations. 3. Chemical Engineering. 4. Chemical Engineering Progress. 5. Chemical Engineering Costs Quarterly (Cost Engineering).

Jan 1, 1958

By W. L. Hill, W. H. Armiger, S. D. Gooch

The physical properties, chemical behavior under thermal treatment, and fertilizer value of fluorine-containing pseudowavellite (hydrous calcium aluminum phosphate) that occurs as phosphate clay admixed with quartz sand in an extensive deposit near Bartow, Fla., were determined by experiments in laboratory, pilot-plant, and greenhouse. When the mineral was heated at 500°C, 80 pct of the phosphorus became citrate soluble. The heated product, however, deteriorates markedly under moist conditions such as obtain in the soil.

Jan 1, 1950

By R. L. Grayson, F. Giana, R. Aspinwall

Small-mine and contractor Fatal Incidence Rates have been a problem for over 20 years in the coal industry, and the rates persist as unacceptably high. This paper briefly retraces historical information and data on the continuing problem and recounts the many unsuccessful efforts and initiatives to address the problems effectively. Next the results of a review of international literature on addressing the problems are presented. After focusing on a method to pinpoint the trouble spots more specifically through a nested data analysis, suggestions are provided on how the problem may potentially be addressed more systematically and effectively in the U.S.

Jan 1, 2006

By Herbert Hoover

BOTH the directors of industry and your leaders have made great progress toward a new and common . ground in economic conceptions, which, I am confident, has had a profound effect upon our economic progress during the last few years. That is the conception that industry must be constantly renovated by scientific research and invention; that labor welcomes those labor-saving devices; that labor gives its full and unrestricted effort to reduce costs by the use of these machines and methods; that the savings from these reduced costs shall be shared among labor, employer and the consumer.

Jan 1, 1930

By Changshou Sun

The Leeville underground mine has been in operation since 2006 and currently produces 3,175 t (3,500 st) of ore per day with an average gold grade of 12.6 g/t (0.4 opst). The mine has a large horizontal extent of 762 by 152 m (2,500 by 500 ft) and a vertical extent of 6 to 61 m (20 to 200 ft). Based on the characteristics of the ore bodies, the deposits are divided into several mining zones. The geotechnical properties of mining zones are also different from one zone to another. A successful geotechnical collection system is very important for mining design and operation in the Leeville underground mine. Three methods are used to collect the geotechnical data in the Leeville underground mine: • Core logging. Most geotechnical data are collected by this method, which is based on exploratory drills and estimates parameters for rock quality designation (RQD), fracture frequency (FF), compressive strength and rock mass rate (RMR). • Site investigation. This method collects more detailed geotechnical data and geostructural data from work done in the underground drifts and stopes. Parameters of RQD, FF, compressive strength, RMR, rock tunneling quality index (Q) and geostructural data are estimated. • Data collected from drill holes made for the critical infrastructure facilities. This method provides the best detailed geotechnical information for areas in which the critical infrastructure located. A complete geotechnical database has been constructed using this geotechnical data collection system. The database can be used for the design of ground support, stopes and stope blasts, among other critical applications.

Jan 1, 2010

By Spooner H. W

The paper describes the search for mineral deposits in an area of 4,500 sq. miles of south-west Tasmania. The area is one of difficult access and the problem of speedy movement and maintenance of field parties was solved by the use of helicopters. The programme has followed a systematic pattern of the aerial photography of the exploration area with the preparation of photQmosaics and topographical base sheets from these mosaics. Geological maps were initially prepared by photogeological interpretation and making use where possible of pre-existing information. The maps produced were later checked by ground traverses. Geophysical maps were obtained by the use of airborne magnetic, electromagnetic and radiometric methods. Geophysical and geological anomalies were checked on the ground by a campaign using ground geophysical equipment in the former case and geological and geochemical work in both instances. Audio Frequency Magnetic and Induced Polarization techniques were used in an area which was covered by several hundred feet of Tertiary sediments.The campaign has reached the stage of the drilling of specific targets.INTRODUCTIONThis paper describes the activities of Lyell-E.Z. Explorations (L.E.E.), an organization which was formed in 1956 by the Mt. Lyell Mining and Railway Co. Ltd. and the Electrolytic Zinc Co. of Australasia Ltd. to explore for mineral deposits in an area of approximately 4,500 sq. miles in southwest and southern Tasmania. To provide the necessary personnel and equipment for this project the exploration resources of both Companies were pooled and augmented and a headquarters was established in Queenstown. The work was directed by a Committee of four made up of officials from both Companies; a review of this structure has recently been presented by Hall (1959).

Jan 1, 1960

By Walshe J. M.

The slow-speed compressor is giving place to the high-speed type, with its greater economy of material and space; and, where very large units are required, the turbo-compressor is supplying the need. In the very large air-supply stations on the Rand, turbocompressor units of a capacity of 20,000 and even 50,000 cubic feet, requiring 4,000 to 13,000 horsepower, are quite a commercial proposition, and have proved a practical success. Air-compressors of this size are, however, very exceptional, and the high-speed reciprocating compressor is quite capable of dealing with the highest outputs so far required in this country and, in the hands of manufacturers experienced in the design of high-speed steam-engines, a very high standard of reliability and efficiency in operation is obtained. The so-called “high-speed” or more correctly quick-revolution type of compressor is now extensively used in mines and collieries; for the air-pressures required for power purposes in mining work, two-stage compression, with an intercooler between stages, is the design usually adopted in best practice. It is not the writer’s intention to describe a variety of high-speed air-compressors but to select as an example of this type of compressor the one with which he is most familiar, and which is probably more largely used than any other, namely, the double-acting two-cylinder two-crank type with automatic light-plate air-valves, and with the working parts lubricated on the forced-lubrication principle. Sectional drawings, efficiency curves, air-cylinder diagrams and other data accompany the descriptions and photographs of compressor design, components and mine applications

Dec 1, 1916

This modern plant was installed with the object of treating all oxide ore and payable dump material by the cyanide process.The plant is located on a ridge on the eastern side of Linda Gully. The mill -site has a slope to the south of 1 in 4.The new plant is of steel and concrete construction and was specially designed to suit the climatic conditions which exist at Mount Morgan.THE COARSE CRUSHING PLANTThe ore received from the, mine is dumped into a 600-ton steel bin which is commanded by a 3 ft. 6 in. gauge railway,The mine ore is conveyed by steam locomotives in rakes of five self-dumping 7-ton railroad cars. The dump material is mostly loaded by bull-dozers and conveyed to the binsin large motor lorries. Located on the top of the bin is a heavy railroad grizzly having 12-in openings through which all ore must pass.The flow of ore from this steel bin is controlled by a No. 7D 3-speed Ross chain feeder. It should be mentioned here that, although the bottom of the steel bin is inclined at an angle of 45°, it has been found, owing to the clayey nature of the oxide ore, that the live capacity of the bin is only about 50% of the total capacity.

Jan 1, 1939

By Edward L. Beutner, Robert M. Crump

Benson Mines low-grade iron ore reserve is a replacement deposit within the Grenville gneisses of the Adirondacks. The average grade of the crude ore is about 23 per cent iron. The iron minerals are principally magnetite and hematite disseminated throughout the gneisses as discrete grains about 1 mm in size. Both the ores that are beneficiated by magnetic means and the non-magnetic ores that are treated by a gravity method of concentration are found in stratigraphically different positions but are mined from one open pit, which is about 2.5 miles long and 800 feet wide and are treated separately. The gneisses are described and named according to the distinctive mineralogy of each. Recognition of the gneissic types permits the interpretation of the structure as a northward-plunging syncline overturned to the west. A large subsidiary anticline-syncline complex occurs on the east limb of the major syncline. Iron minerals in sufficient quantity to be considered ore are confined to areas where the footwall rock has been overturned to become the hanging wall.

Jan 1, 1968

By Richard T. Stain

"In 2001, a pile trial site was established at Limelette in Belgium consisting of 25 displacement screw piles and 5 driven pre-cast piles. Interested parties were invited to participate in a pile prediction event, whereby they would submit predicted static load test behaviour in the form of load settlement plots. These predictions could be based on soil investigation results supplied by the organizers, or dynamic load test measurements.Following the submission deadline, the organisers released the results of static load tests for comparison.Of all the six participants, including Statnamic, the SIMBAT method was independently accredited with achieving the best predictions.This paper examines at the differences between SIMBAT and other systems, and presents the correlations from the Limelette trial.INTRODUCTIONThe Belgian Building Research Institute (BBRI) initiated an ambitious research programme involving the construction and testing of some 60 trial piles spread between two sites, a clay site at Sint Kateline Waver and a sandy site at the BBRI headquarters at Limelette. The project was financed largely by the Belgian Ministry of Economic affairs. (ref 1.) This paper refers only to the second site.At Limelette, six different types of displacement pile were installed: one driven pre-cast and five cast in place screw piles - Atlas, DeWaal, Fundex, Olivier and Omega. A detailed site investigation was carried out including in-situ and laboratory tests.An international pile capacity prediction event was publicised, participants being invited to predict static pile behaviour. Predictions could be based on:"

Jan 1, 2005

The use of comparative sampling methods during the evaluation of the tin-copper deposits at Cleveland mine yielded closely checking average results from groove, channel, AXT split diamond drill core, and bulk sampling for both tin and copper content of the ore.The weighted mean tin and copper grades and values for the groove, channel, and split core samples showed small percentage differences from bulk sample results, and the F-ratio test for single population origin of the four types of samples was accepted at the 99· 5 per cent level of confidence.These results indicate that grade estimates based on the assays from AXT split diamond drill core and/or groove samples would be reliable within practical limits.

Jan 1, 1968

By Vishwajeet Ahuja, Benoit Jones

"INTRODUCTION Shotcrete lining forms an integral part of conventional tunneling and is widely applied for underground excavations. Early strength gain of the shotcrete is a crucial aspect for ground support and safety of operatives. Strength requirements are dependent on various factors such as lining thickness, ground type, excavation size and tunnel depth. The early strength gain is typically monitored using destructive tests, such as needle penetration, stud driving or coring samples for uniaxial compressive strength testing in the laboratory. Being destructive, these tests cannot be directly performed onto the lining without causing damage that must be repaired, which is a particular problem for permanent linings. For this reason and to avoid the need for operatives to work near to exposed ground and/or fresh shotcrete, these destructive tests are often performed on panels, which are sprayed at the same time as the tunnel lining. All current testing methods are also very local, testing only a small part of the lining or a panel, which may not be representative because the temperature history could be significantly different. Therefore, these tests do not provide an accurate or complete picture of the lining strength gain. New testing methods that are non-destructive and can scan the whole lining remotely would be extremely desirable. This paper describes a new method, using thermal imaging techniques, that achieves these aims. It also discusses the real-time on-site application of the method, providing insight into the experience gained and conclusions derived. Shotcrete Shotcrete used for tunnel linings requires immediate strength development. The strength development is a direct result of the hydration reaction of cementitious materials present in it. A progressive sequence of the hydration reaction changes it from a solid suspension (typically referred to as fresh concrete) to a solid skeleton with a porous network and thereafter, into a solid with predominantly discontinuous pores (Byfors 1980). In the case of shotcrete, early strength is needed to support the self-weight and then continuing early age strength gain is required to begin to support ground loads. These strength requirements, along with other workability needs, are met by careful concrete mix design, the use of admixtures, such as accelerator and superplasticizer (BS EN 934-5 2007), and supplementary cementitious materials, such as silica fume."

Jan 1, 2016

By Neil T. Russo, Peter M. Kandaris, Jogi S. Gadok

"Assessment of subsurface data for foundation design in support of long high voltage electric transmission lines is best accomplished using a probabilistic strategy since only a small portion of structure locations are typically sampled. Probabilistic approaches provide a tool to evaluate site uncertainty in a systematic and rational manner. This paper provides a case history of a risk-based design approach for a recently completed 191-mile long 69/161/345kV steel monopole transmission line traversing Central Iowa. The project owner made available limited subsurface information at project initiation, requiring the design team to obtain additional data within a constrained budget for 1067 large diameter, laterally-loaded deep drilled shaft reinforced concrete piers. The team commissioned a geologic desktop study to reduce uncertainty in subsurface evaluations and aid in selecting additional sample sites. In total, investigation programs tested approximately 15 percent of structure sites. The paper details the probabilistic approach used to estimate foundation geotechnical design parameters, with information from the various studies categorizing strata both laterally and with depth. Low-bound parameters were estimated via a statistical approach at a predetermined reliability level. Significant savings resulted from this approach when compared to conservative deterministic processes. Project QA/QC logged subsurface soil conditions during foundation excavation, then compared as-found conditions to the conditions assumed for design. The team redesigned foundations if either a non-conservative variance in soil conditions was observed or if bedrock elevation differed significantly from design assumptions. As a result, only 22 out of 1067 foundations required modification during construction (2% variance from initial design) with negligible impact on the construction budget and schedule.INTRODUCTIONFoundation design for long high voltage transmission lines presents a unique challenge in that the assessment of subsurface conditions typically requires substantial data that may or may not be obtainable. Investigations are usually performed well in advance of construction, often with limited access to structure sites and typically in remote areas. Probability and risk-based investigation and design strategies offer an opportunity to systematically estimate subsurface profiles and geotechnical design properties with limited data. Risk can be further reduced with dedicated field inspection of foundation construction along with good field and design team communication during construction. This paper presents a case history of probabilistic methods used for the investigation and design of electric transmission line foundations."

Jan 1, 2017

By K. H. Johnston

This guide was written to furnish the coal industry with a description of techniques, instruments, and clues on how to find abandoned oil and gas wells that have penetrated coal seams. The report includes specific information on searching techniques currently in use by several coal mining companies, gas-transmission companies, and waterflood operators, as well as information on State agencies responsible for the enforcement of laws and the preservation and distribution of data pertaining to the drilling, development, and abandonment of oil and gas wells. Comparative tests were performed with several commercial electronic metal detectors to determine the feasibility of using them to aid in the search for abandoned wells and to determine the instrument most suited for that particular use. The role of methane detectors to locate abandoned wells is described, including a case history. Tests were made to develop an efficient procedure to follow in systematically searching an area for metallic clues or hydrocarbon evidence to abandoned wells. The guide describes, in detail, a search sequence, including the collection of basic data, preparation of the selected area, and the physical search. Methods are given for evaluating the results.

Jan 1, 1973

By H. P. Greenwald

"INTRODUCTION In the course of its studies of the explosibility of various coal dusts in the Experimental coal mine, the Bureau of Mines has tested coals representing the entire range of volatile content found in the United States. In connection with their work the Bureau's field engineers some¬times meet operating officials who are not impressed by the fact that there is an explosion hazard in mines working low—volatile coals. Actually the difference in explosion hazard between high—volatile and low—volatile coals is one of degree and not of kind. The purpose of this paper is to set forth briefly the experimental evidence that has been accumulated on the explosibility of coal dusts containing 8 to 31 percent volatile matter on a dry, mineral—matter—free basis.There have been numerous dust explosions in mines in which coals were worked that have compositions within this range. Those explosions are listed in an appendix, together with a bibliography of Bureau of Mines papers describing explosion tests in the Experimental coal mine."

Jan 1, 1940

By F. Baerhold, S. Mitterecker

"Acid recovery is an important process step in pickling and leaching processes. Pyrohydrolysis in spray roasters and fluidized beds is a well-established technology to recover hydrochloric acid, but the hydrolysis in the liquid phase is more and more considered as an alternative new process route. The characteristic features of these three processes will be discussed along with select industry trends. For example, hydrochloric acid based leaching processes for ilmenite and nickel laterite ores produce far larger volumes of waste acid streams than the steel industry. Scaling-up of the spray roasting technology to the highest possible capacity is necessary in order to become more cost effective. In addition, process routes based on ferric chloride pyrohydrolysis allow the production of super-azeotropic HCl (up to 30 wt.%). Finally, the new ECOmode concept optimizes the operation of both pickling lines and the spray roast acid recovery plant. Long term results from industrial applications show that fuel savings in the spray roaster of 25% are easily achieved without additional process steps. An attractive feature is also to upgrade existing installations to higher plant capacities.INTRODUCTION Pyrohydrolysis is the conversion of metal halides into metal oxides at elevated temperatures in the presence of water vapor. Reaction products are a hydrogen halide gas and a metal oxide. The process was originally developed and introduced into the market by ANDRITZ Ruthner in the 1960’s. It has found wide technical application in the field of acid recovery and oxide production. The introduction of this process has revolutionized pickling technology. The use of hydrochloric acid has strongly increased over the last decades, since pyrohydrolysis is available for the total recovery of waste pickle liquors from mild steel pickling, as illustrated in Figure 1.Chloride media are also used increasingly in the metallurgical industry. Oxide production processes for Mg, Co, Ni, and Al have been installed. Processes using hydrochloric acid are known for the leaching of ores as well as for the re-extraction of metals from organic solvents. In both cases the recycling of HCl is of substantial importance to achieve highly economic processes and to reduce waste."

Jan 1, 2016

By Satyam Tiwari, Sarat Kumar Das

Tailings from mines and industries impose danger to the environment as evidenced by the recent failures of tailing storage dams. The tailings are mostly non-plastic with silt-size particles, but their behavior is largely dependent on the extreme void ratios of the material. Hence, the critical state provides an appropriate perspective in explaining the behavior of these geomaterials. Based on a comprehensive dataset of non-plastic tailings and non-plastic soils, an attempt has been made here to correlate critical state parameters to extreme void ratios and stress parameters. A hybrid algorithm with multi-objective feature selection (MOFS) and extreme learning machine (ELM) was used to establish the correlation and to identify the most influential input parameters. Based on the information from the proposed hybrid algorithm, a comprehensive prediction model is proposed using multi-gene genetic programming (MGGP) algorithm to facilitate quick estimation of critical state parameters. The performance of both models has been assessed using several performance metrics. The results from the study indicate that hybrid MOFS algorithms perform very well in the prediction of critical state line parameters and the identification of influential features. The findings of the study have significant implications for future research on the safe management of tailing storage facilities.

Dec 22, 2023