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By E. H. Hamilton

THE furnace on which the following investigation was based had dimensions 48 by 160 in., and was in continuous operation during the three days of the test. The average charge consisted of PER CENT. LB. PER HOUR Bed ore?14.5?2,980 Roast from Dwight-Lloyds?44.5?9,160 Siliceous ore?3.5?720 Iron flux?2.1?430 Battery plates?0.5?103 Lime rock?23.9?4,925 Briquettes?4.0?825 Scrap iron?2.1?430 M. P. slag?4.2?865 L. P.speiss?0.7?142 Total 100.0 THE furnace on which the following investigation was based had dimensions 48 by 160 in., and was in continuous operation during the three days of the test. The average charge consisted of PER CENT. LB. PER HOUR Bed ore?14.5?2,980 Roast from Dwight-Lloyds?44.5?9,160 Siliceous ore?3.5?720 Iron flux?2.1?430 Battery plates?0.5?103 Lime rock?23.9?4,925 Briquettes?4.0?825 Scrap iron?2.1?430 M. P. slag?4.2?865 L. P.speiss?0.7?142 Total?100.0?20,580

Jan 1, 1924

By F. Dahl, P. Raleigh, J. Holzhauser, B. Nilsen

Tunnel excavation using tunnel boring machines (TBMs), has become increasingly common in recent years, despite the fact that precise evaluation of certain risks have not kept pace with the use of these machines. One of the risks easily overlooked by Engineer and Contractor alike are the effects of abrasive ground on the costs and schedule of a given project. The impacts of worn and damaged TBM cutter heads have been observed on hundreds of tunnel projects around the world. It would appear that a reliable prognosis of the abrasiveness of soils on a project would be of great importance for designers, clients and contractors alike. Several well acknowledged test and prognosis methods already exist for rock, however there is only very limited knowledge available to describe the abrasiveness of soil and its impact on soft ground TBMs. This paper will examine approaches to this problem and suggest a new approach based on a current project undergoing design.

Jan 1, 2007

By Randy Wheeler

One of the more difficult topics to address concerns the effects of vibration on historic structures. Not only blast induced vibration, but also vibration from other transient and semi-continuous sources like, traffic, human activity, and environment forces. A common question might be, “What level of blast-re l a ted PPV is considered safe?” A review of some of the papers available from the ISEE Explosives Reference Database on CD ROM shows that 0.50 inch per second was often used. It was not clear on what basis this value was selected except that it represents the low frequency limit for plaster developed by the United States Bureau of Mines in RI 8507. In another case, a limit of 0.20 inch per second was mentioned, apparently simply because it was ten times less than 2.00 inches per second.

Jan 1, 2004

By QINGXIANG CAI, Lin Li, PENG LIU, IZHAR MITHAL JISKANI, XIANG LU, Wei Zhou, YONGLI ZHOU

The concept of green mining is to improve the mining industry in a holistic way so that it is safe, efficient, and environmentally sustainable. The purpose of this study was to develop an evaluation index system of green surface mining based on the theory of green grades. The evaluation model is comprised of three attributes (safety, efficiency, and environment), nine criteria, and 35 indicators. The fuzzy comprehensive evaluation method was used to determine the weights of indicators by taking into consideration degree centrality, closeness centrality, and betweenness centrality. Findings indicate that the environment is the most critical aspect of green surface mining, followed by efficiency and safety. The top five ranked green mining success indicators were the application of new technology, starting-off-rate of equipment, science and technology input to total investment, the number of accidents (decreased), and the production (increased). It was observed that more improvements are needed to overcome water, air, waste, and sound pollution. Attention should also be paid to land reclamation and post-mining land uses, which are key factors in green mining. The proposed model can be applied to evaluate and improve the level of green surface mining in other regions. This study provides a tool for decision-makers that can offer technical assistance to green mining.

May 26, 2020

By S. Kawatra, K. Lewandowski

Heap leaching efficiency is reduced by poor solution flow characteristics (channeling and ponding), which result from fines migration. Agglomeration of the ore can immobilize fines, but copper leaching requires an acid-resistant binder to stabilize the agglomerates. Until now, there has not been a satisfactory way to evaluate whether a binder was effective, other than squeezing a handful to see if it “feels right”. We have developed procedures to quantitatively determine whether a binder gives good performance in an acidic solution, and have identified several binders that will be suitable for copper heap leaching.

Jan 1, 2007

By Jessica E. Heuchan

An industry survey has been conducted by the Queen's University Mining Engineering Department of 30 Canadian mining organizations to determine how effectively newly graduated mining engineers meet the needs of the industry. The principal objectives of the survey were to evaluate, and thus provide focus on change for, curricula being taught at Canadian mining engineering schools in service of the industry's needs; to provide feedback on current industry expectations; and to reinforce contacts with the industry as a means of providing future collaboration. A strong focus of the survey was placed upon industry's perception of the special attributes of engineering hires and applicability of student academic training to meet their industrial requirements. In providing this detailed summary of corporate responses, a clearer understanding of the mining industry's expectations of engineering training at Canadian colleges and universities has been gained.

May 1, 2003

By B. J. Moore

This Bureau of Mines publication contains analyses and related source data for 276 natural gas samples from 23 States. All samples except four were collected during calendar year 1984. Those four samples were collected earlier, but releases granting permission to publish were not received until 1984. All samples were obtained and analyzed as part of Bureau of Mines investigations of the occurrences of helium in natural gases of countries with free market economies. This survey has been conducted since 1917. The analyses published herein were made by the mass spectrometer and chromatograph. The results of these investigations are published annually to make the information available to the petroleum industry and the general public. Twenty-eight publications have presented the results of 13,957 gas analyses made prior to 1984. The first three bulletins (1-3)2 contain analyses and related source data on 5,218 gas samples collected from 1917 through 1960; these bulletins have been supplemented annually by information circulars (4-17, 19-24, 26-28) containing 8,453 analyses of samples collected since 1960.

Jan 1, 1985

By S. Cotten

The regulations for current coal mine refuge alternative (RAs) require that there be sufficient life support to sustain survival of the maximum number of RA occupants for a minimum of 96 hours. This minimum duration assumes that rescuers can access the RA through the mine within four (4) days of the onset of the mine emergency. But what if mine rescue teams cannot reach the miners within the RA before the RA air supply is severely limited or exhausted? What could be done to extend the duration of the RA life support capability into the 97th hour and beyond? In addition, what might be done to enable more rapid rescue of the miners if they could not be reached through the mine in a timely manner? This paper describes a systems approach to address the potential need to extend the duration of RA life support beyond current design limits. New capabilities that need to be developed in advance of such a dire need include more reliable emergency communications, highly mobile and efficient drilling rigs, enhanced directional drilling techniques, and a standardized RA external life support interface along with RA internal design modifications to accommodate use of an external supply. The following sections describe the need, intent, and technology gaps associated with each of these capabilities. Government agencies and the mining industry should consider initiation of a program to investigate, design, and develop effective means of extending the current 96-hour time restriction on coal mine refuge alternative life support. The development process should begin with a focused study to refine the overall operational concept, investigate the current state-of-the art of critical technologies, identify specific technology development priorities, and make recommendations for a development program to provide in an organized, efficient, and timely manner a solution for extended refuge alternative life support and occupant rescue.

Jan 1, 2011

By D. D. Faulkner

Cable bolts anchored with traditional two component polyester resin cartridges have successfully supported difficult roof conditions in underground mines. Resin cartridges provide a cost-effective cable bolt anchoring system with consistent anchorage performance characteristics when properly installed. The most commonly used cable bolts in the U.S. mining industry are 270 ksi (1,862 MPa), 0.7 and 0.6 inch (18 and 15 mm), seven-strand smooth cable with resin mixing bulbs (also known as bird cages), and 40- and 30-ton nominal capacity, respectively. However, there are other types of cable bolt anchoring systems aside from bird cages. Recently, many questions have been raised regarding the anchorage characteristics of various types of cable bolts. Keystone Mining Services, LLC (KMS), the affiliated engineering company of Jennmar Corporation, conducted a variety of controlled tests developed to closely model actual underground installations. These tests compared the performance of three commonly used cable bolt varieties, including plain, bird caged and indented seven-strand cable. Details of the laboratory testing and comparative analysis of the results are provided.

Feb 23, 2014

By V. F. Parry

"INTRODUCTION During the war period the Bureau of Mines expanded its investigations on western coals principally in connection with Investigations of raw material resources for western steel production. Owing to the expansion of the steel industry, there was some concern regarding the availability of suitable coking coals; end because of the potential steel shortage, the production of sponge iron, using the lower-rank fuels, was considered. Work was conducted by the Bureau of Mines on exploration projects and on testing of coals both at the Central Experiment. Station at Pittsburgh, Pa., and at the Bureau of Mines Station at Golden, Cole.The results of these investigations are being published by the Bureau in several reports of investigations and technical papers. In making this resume of coal investigations, the work done by the Bureau of Mines at Pittsburgh in the Mining and Coal Carbonization Sections will be discussed and the investigations at Golden described in greater detail.INVESTIGATIONS OF WESTERN COALSThe Mining and Coal Carbonization Sections of the Coal Division, Bureau of Mines, under the supervision of A. L. Teeny es and J. D. Davis, respec¬tively, conducted many field investigations to locate and evaluate new sources of coking coals. Drilling explorations were made in Colorado, Wyoming, Utah, New Mexico, and Washington and revealed two important new reserves of coking coal. The first one studied was the Willow Creek bed at Kemmerer, Wyo., which was reported in 1945.3/ A recoverable reserve estimated at 11,200,000 tons was blocked out, and samples of coal were extracted for coking tests. The coking properties of the coal were not quite equal to those of Sunnyside coal, but it was indicated that a 50-percent blend of the Willow Creek with Lower Sunnyside will produce a satisfactory metallurgical coke based on Columbia steel standards."

Jan 1, 1948

P. H. Dudley, Yew York, N. Y. (communication to the Secretary*) :—The characteristics of Professor Home's metallurgical papers are, that he is able, from the mass of confusing evidence on the subject, to make an analysis and present hypothetical and essential principles in concrete form for consideration and discussion. I can appreciate, from the practical side of the subject, the labor of collecting and investigating the data which was essential to prepare the paper. Much of it necessarily came from material of preceding years of manufacture in which time was allowed for chemical reactions of the re-carburizer, and for the elimination of the oxidation-products before teeming the ingots. This practice gave a favorable time-element to free the metal from slag and other impurities— a requisite condition for the production of sound steel in the ingots. But, in allowing them to become cold before they were charged into the furnace, a subsequent time-element entered as a detrimental factor in the development of the pipe or shrinkage-cavities, which gave an ingot-structure deficient in soundness, at least in the upper portion. (The term slag is used in a general rather than in a strictly technical sense.) Traces of manganese sulphide are often associated with manganese silicates in the same thread or seam, and at other places they are separate and distinct. Interpretations from material thus manufactured must be made with due allowances for the methods of fabrication and the requirements of service. The only way we now have to estimate what the degree of soundness of the ingot-structure was, in the early foreign and American manufacture of steel rails, is by examination of the worn and failed material after years of service. We must remember also that the poorest material was long since consigned to the scrap-heap without any full record of its history. The rails from a given ingot cannot now be identified ; and in many

Jan 1, 1909

By R. K. Zipf

A method is presented for creating realistic numerical models for practical coal mine ground control. The method includes procedures to collect the necessary mechanical input parameters from a geologic core log, procedures to set up a model and procedures to interpret calculation results. The input parameters come from a detailed geologic core log and extensive point load tests of estimate rock layer strength. A suite of material property input parameters is proposed which allow the user to go from core log to numerical model inputs. Rock bolt anchorage properties are also linked to the material properties of each geologic layer in the model. Following this procedure leads to very realistic calculations of the rock failure process and rock support system behavior. These calculations in turn enable realistic comparison of the effectiveness of alternative rock support systems.

By G. Papachristodoulou, O. Trass

"Performance data for both wet and dry grinding of materials have been obtained in this novel, planetary ring-roller mill over wide ranges or operating conditions. The Szego mill consists of a stationary cylindrical shell inside which grooved, radially mobile rollers rotate, driven by a central shaft. The mill has several internal design variables such as number, diameter and length of rollers as well as size, shape and pitch oi helical grooves. It is compact, has a high specific capacity, modest power consumption, and can grind many materials down to ultrafine powders. Illustrative data on product fineness and mill power consumption are given along with results from studies on grinding kinetics.INTRODUCTIONThe extensive use and importance of grinding as a unit operation, coupled with the rather low energy efficiency of conventional equipment provide a challenging incentive to investigate novel methods of comminution. Yet, most current development work is taking place in mill performance modelling and optimization, or with various detailed improvements rather than in the field of new equipment development.This paper is a report on the development of a ring-roller mill invented by the late L.L. Szego which embodies several novel concepts. The mill has a broad range of applications, may be operated wet or dry, and can grind materials down to ultrafine sizes with modest energy consumption. It has been developed by General Comminution Inc. in close cooperation with the University of Toronto."

Jan 1, 1986

By A. Wahab Khair, W. M. Devilder

"This paper presents an analysis of fragment size distribution and characteristics of fracture surface in coal cutting using a rotary coal cutting simulator. Coal cutting by a drum type continuous miner was simulated in the laboratory. A series of tests along both the face and butt cleat direction of coal under different operating and in-situ conditions were performed. In each experiment the cut surface was photographed microscopically and the coal cuttings were collected and sized. Data were used to show how and to what extent various parameters effect size distribution of the coal cutting and how this correlates with the characteristics of the fracture surface. This study resulted in establishing a number of distinct correlations between the size distribution and fracture surface. These correlations were primarily based on the degree of interaction between adjacent bits and the amount of bit-coal interaction taking place on the cutting path. Some of the major results of this study are as follows:Zones of bit-coal interactions proved vital toward understanding the effect the conical bit has on the fragmentation process. This in turn led to the identification of areas which are responsible for the production of fines and generation of respirable dust.The various parameters employed in the coal cutting experiments which showed a strong effect on the coal fragment size distribution were: bit type, bit spacing, depth of cut, in-situ stresses, and cleat orientation. Bit angle and cutting head velocity exhibited the least effect and no correlation was established.From this study it is obvious that the key to achieving efficient coal fragmentation is to limit the degree of bit-coal interaction that takes place throughout the bit path while causing maximum interaction between adjacent bits. Accomplishing this not only increases the percentage of large fragments produced but limits the amount of secondary crushing that takes place in the bit path thus resulting in decreasing fines and consequently, the amount of respirable dust generated.Over 2,000 continuous mining machines (introduced in the 1950's) equipped with conical bits or point attach bits account for well over half of the United States' production from underground coal mines. Today, competition in the coal industry has increased, due mainly to coal market conditions and legal restrictions, thus placing an emphasis upon increasing production, efficiency and health/safety of the workers. Mine operators are always interested in finding the most efficient performance of continuous mining machinery to produce the largest amount of size of coal at the lowest cost. An increase of fine material sent to the cleaning plant can seriously overload the plant to the extent that plant efficiencies deteriorate significantly (1). Also, the difficulty and expense of cleaning very small particles often cannot be done economically and thus, thousands of tons of coal are sent to the refuse pile because of costly or ineffective cleaning facilities. It has been said, ""the efficient extraction of coal or rock implies breakage into a size range that contains a minimum quantity of very small sizes"" (2). All known fragmentation theories concur that more fragmentation requires more energy (3). So, the importance of reducing fines is already evident from an outlook upon efficiency.Now, let's consider another view point., duet generation."

Jun 1, 1988

By Hongyang Cao

The iron constituents selectively separated from the modified copper slags by magnetic separation and flotation.were studied. The results of magnetic separation for modified copper smelting slags show that the grinding size, current intensity and dispersant agent had great influence on grade, and recovery ratio of TFe in preparation concentrate; The results of flotation for magnetic concentrate show that the positive flotation of sodium oleate negatively upgrade the grade of magnetic concentrate, but the reverse flotation of lauryl amine and soluble starch are effective. The grade of TFe can reach 54% and the recovery ratio can reach about 90% in magnetic concentrate, when the grinding size is 45.8µm and the current intensity is 2.5A. The optimal effect is obtained by using lauryl amine as collector and soluble starch as depressant to reverse flotate magnetic concentrate, and the grade of TFe is upgraded 2.37%.

Jan 1, 2009

By Juan Carlos Salas

In this paper, a collaborative R&D model which has been successfully applied by a global mining companies association is presented and analysed both from the conceptual and practical point of view and an example of these collaborative initiatives, the Copper Technology Roadmap recently generated by a group of the most relevant copper mining companies, is presented, including an analysis of strategic opportunities and challenges in the Latin American region.

Sep 9, 2007

By J. B. Lott

The authors' company has recently undertaken a development programme aimed at exploring the relationships between the variables of greatest importance in the design of mixer-settlers for metallurgical solvent extraction applications. Such applications vary from relatively small scale plants treating copper mine waters, nickel containing effluents, etc., where the total flowrates may be of the order of a few hundreds of gallons per minute, to very large scale plants treating several thousands of gallons per minute of leach liquors containing copper, uranium or other metals. This paper outlines the physical and mechanical factors which must be taken into account when designing mixer-settler systems for large scam. solvent extraction plants. The performance of the equipment will also be dependent upon the chemistry of the system, including the kinetics and thermodynamics of the ion exchange reaction itself, the effect of impurities flocculants, surfactants, temperature, etc., but these will not be dealt with here. Much of the laboratory work has been carried out using copper containing solutions and either LIX 64* or LIX 64N* as the solvent dissolved in various grades of kerosene. For simplicity, all the graphs and tables of results which are presented and discussed here will refer to the LIX-copper system, although the conclusions will in many cases be generally applicable to other systems also. The LIX-copper process is now sufficiently well known to obviate the need for a full description, however, an outline flowsheet of the process is shown in Figure 1. The ultimate objective of a laboratory programme for a particular extraction application is to provide data upon which a mixer-settler system can be designed to handle a given throughput of leach liquor and extract from this liquor the maximum quantity of metal for the minimum cost. In other words, the objective is to determine the design and operating parameters which achieve the optimum balance between capital and operating costs. * Trade-marks for General Mills solvents.

Jan 1, 1971

By John R. Dudo

The Bureau of Mines Morgantown Petroleum Research Laboratory, with the cooperation of the Penn York Oil Company, cored the Dewdrop, Bradford Third, Lewis Run, and Sartwell sands in the Sartwell oilfield, McKean County, Pa. This report contains a review of the geology and depositional history of the field and an evaluation of the feasibility of secondary recovery of oil from the Bradford Third and Sartwell sands by waterflood or gas drive. Core analysis, geologic data, and electrical and radioactivity logs were used to evaluate the reservoir characteristics. Reservoir geometry, rock properties, fluid characteristics and saturations, and relative permeability-saturation relationships were used to assess the floodability of these two sands. The results of this study indicate that between 53,000 and 61,000 barrels of oil can be recovered by water or gas injection. The success of a waterflood or gas drive will depend on the field injection rates of the reservoirs comprising this oilfield. Following an economic evaluation, additional field work is recommended to further test the floodability of the reservoir.

Jan 1, 1967

By K Nilsson, D Connelly

Troy Resources acquired the Karouni Gold Project in Guyana, South America in 2014 and immediately proceeded to a Pre-Feasibility Study and project implementation. The study considered two open pit mines feeding a conventional carbon in leach (CIL) gold plant with a capacity of 1Mtpa. The study assumed a total of 2.61 million tonnes of ore with an average grade of 3.84 g/t gold with a recovered gold production of 303,526 ounces over a three year mine life.The project development involved drilling metallurgical test holes, securing second-hand major pieces of equipment where suitable, and arranging shipping to Guyana. The remote location meant logistical considerations were paramount. The plant consists of conventional two-stage crushing with single stage ball milling and a gravity circuit. The tailings circuit includes DETOX.The extremely high rainfall presented challenges with water management and the necessity to dispose of clean water to the environment. The DETOX was also mandatory due to the highly sensitive environment and past history in the area. The criticality of this meant that in the design, any cyanide in the tailings would precipitate in a plant shutdown.Lessons were learned and the project has been both profitable and successful for Troy Resources in a new operating location. In addition, the project has created jobs, delivered royalties and brought new skills into an area where previously there was little current mining activity.CITATION:Nilsson, K and Connelly, D, 2015. Karouni Gold Project from drill core to commissioning, in Proceedings MetPlant 2015, pp 197–206 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

This paper characterizes the copper cycle, that is, the flows of copper entering and leaving the African economy over a one-year period (1994). The major flows over the entire life-cycle of copper are examined; these include production (mining, milling and refining), fabrication of semi-products and manufacturing of finished products, use, and the waste management system. The results reveal that substantial amounts of copper (of order705 Gg/yr) are mined in Africa; of that amount, about 70 per cent is exported following processing, 18 per cent is utilized by African fabricators, and 12 per cent is discarded. The flows of copper products from African fabricators and product imports from other continents exceed product discards by large amounts. This difference, about 0.25 kg Cu/capita/yr on average, is added to in-use stock, largely as wire, plumbing tube, and in electronics. Some 65 per cent of the copper in discard flows is contained in electrical and electronic products, where it is relatively easy to collect and process for reuse. About a third of the copper discard flows known is recycled. The actual percentage is almost certainly higher because of informal (and unrecorded) recycling. Much of the remaining discarded copper is diluted into the municipal waste stream, where recovery and recycling are probably not economically justified. Keywords: material flow analysis, resource management, material budgets, copper, stocks and flows, systems analysis, Africa, developing country

Jan 1, 2003