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By N. Edmonson

The demand for sulfur divides into two major categories: agricultural and industrial. Most of the agricultural demand is related to the production of phosphate fertilizer products. Industrial demand is derived from the demands for a large number of products and is related to a variety of industrial processes, no one of which characterizes it in a simple way.

Jan 1, 1994

By Robert E. Baker

Cortez Gold Mines, the United States' third largest primary producer of gold, commenced continuous operations on January 10, 1969. The decision to proceed to production was made in March of 1968 and construction of the mill and stripping operations for the pit began in April and July, respectively. Anomalous conditions on the slope of Mt. Tenabo along the Roberts Mountain thrust fault zone were discovered by the U.S.G.S. while conducting geochemical surveys in the old Cortez silver district. Following the discovery of gold an intensive program of drilling was organized. Drilling outlined an orebody with 3.5 million tons of ore averaging 0.28 ounces of gold per ton. It was on the basis of this reserve that a 1700 t. p.d. cyanide plant was designed. Needless to say, with such a limited ore reserve, economies in design and construction would have to be observed. Cortez Gold Mines is a joint venture with American Exploration & Mining Co., The Bunker Hill Company, Vernon F. Taylor, Jr., and Webb Resources, Inc. , as partners. American Exploration & Mining Co. is the operating partner.

Jan 1, 1969

By John J. Schanz

The ideal entering freshman for the College of Mineral Industries possesses the necessary aptitude to complete successfully a difficult technical curriculum, has a highly developed intellectual curiosity and adequate preparation in basic mathematics, sciences, and English, is enthusiastic about pursuing a career in the mineral industries, and puts forth a good academic effort while attending Penn State. The present programs of the University?s Division of Counseling and the College of Mineral Industries are directed toward providing the College with students who will meet these requirements. At present, freshmen are admitted to the Pennsylvania State University without entrance examination if they are in the upper two-fifths of their high school classes. All Pennsylvania students in the lower three-fifths are required to take the University Aptitude Test and all out-of-state students the College Entrance Board Examinations. Such students are admitted only if they score sufficiently high on either test to indicate the ability to do satisfactorily the work of University students. Only to this extent, are native intelligence and areas of greatest aptitude known for the Freshman prior to admission, and they are, therefore, largely beyond the control of either the Division of Counseling or the College of Mineral Industries. Because all freshmen, with exceptions that are numerically minor, are required to select a curriculum before admission to Penn State, each student who presents himself for required counseling during the summer, prior to his first semester, has already made a choice of his course of study. In many instances, such choices have been made without a rational and serious consideration of the student?s abilities and interests. Through tests given between the date of admission and the date of the counselling interview, it is possible to measure these characteristics and for the Division of Counselling to advise the student of his chances of success in his chosen curriculum. If he is qualified for the curriculum he has selected, Counselling Service goes on to direct the student?s attention to those other curriculums which are in the same general area as the one he has chosen and which will also challenge his abilities and correspond to his interests, Through this counselling, the curriculums of the College of Mineral Industries, which are often less well known to high school students than others for which they are no more qualified by ability or interest, are brought to the attention of the incoming freshman.

Jan 1, 1959

By T. R. Ellis

The author is the leader of the Extractive Industries Task Force of the International Valuation Standards Committee. The Task Force has developed an Extractive Industries section for inclusion in the International Valuation Standards (IVS). The Extractive Industries Guidance Note provides comprehensive standards for valuation of all minerals and petroleum industry property types for all valuation/appraisal purposes. The document is scheduled for release as an exposure draft for public comment by December 2003, then it will be finalized for publication in the IVS in mid-2004. This paper discusses the content and philosophy of the Extractive Industries Guidance Note within the context of the framework of the IVS. It also discusses the international implications and implementation of this IVS addition.

Jan 1, 2004

By Ali Sogue, Steven Schurman, R. Jensen

This paper presents the results of the remediation of the Gregory Gulch #1 Superfund site, an EPA Clear Creek Superfund project located in central Colorado. The Gregory Gulch #1 site was an historic gold mine and mill located within the city limits of Central City, Colorado. Remediation efforts included the use of the Envirobond™ additive to chemically bind the metals in 3,000 tons of acid generating mine waste that contained high levels of arsenic, lead, zinc and mercury. The toxicity of the mine waste amended with Envirobond™ was not only reduced to RCRA TCLP standards but also to the more stringent UTS standards. The final cost of the treatment was much less than standard industry solidification processes and significantly less than offsite disposal options.

Jan 1, 1999

By K. Y. Vasioutchkov, Y. F. Vasyuchkov, B. M. Vorobjev

In general a term "unconventional mining or "non-traditional mining technology" getting more and move familiar to the mining engineering media. There are several alternating terminological combinations such as "in situ mining", "borehole mining", "shaftless mining", "mineless mining", "geotechnology" etc.; specific terms denote particular method of unconventional mining technology: "underground coal gasification in situ", "underground coal combustion in situ", "borehole hydraulic coal mining" and others. Principal scheme of unconventional coal mining technology is shown in [Figure 1:] One of the greatest potential for coal utilisation during the beginning decades of on coming cetury is the synthetic fuel-gas derived from coal as a product of coal gasification. It is quite logical to enrich this gas before burning it with natural gas, that is methane, contained in coal measures. Thus it is reasonable to suggest a new concept of unconventional coal mining and utilization technology featuring integrated methane drainage with coal-gas combined cycle. Proposed unconventional technology of coal mining is characterized with: - opening up a coat deposit through boreholes, drilled from the surface and used for coalbed methane drainage as well as for coat gasification in situ; - aggregation of methane producing and coal gasification station on mining side with thermo power plant on the electric power generation side in one integrated industrial enterprise. The further improvement of the conventional coal mining technologies both surface and underground could give only insignificant results in economical, ecological and social aspects, but would not be able to provide basic requirements of the XXI-st century. Significant increase in economical efficiency, cardinal humanization of coal mining and basic improvements in environment protection would be achieved through introduction and implementation of innovative or unconventional coal mining technology. These considerations are applied on both coal production and coal utilization sides as far as coat based energy generation is concerned. Now a general opinion is widely spread that an application in the same manner of the traditional technologies of coal mining and electric power generation would inevitably cause further irreversible damage of the global eco-system, notwithstanding the certain environment protection measures being taken. Keeping the recent pace of the eco-system degradation the whole our civilization would be in danger. Thus the solution of this problem is to be found in developing, promoting and implementing in industry unconventional coal mining and modern advanced clean coal technologies. Coal reserves with favourable conditions at shallow depths are -being rapidly depleted in all countries with developed coal industry. So in nearest future more coat will be mined from deeper levels with higher operational expences and with lower labour productivity. For example in Russia only 20% of proven coal reserves can be specified in quality as easy mined reserves, i.e. coal reserves with a good minability. Unconventional (borehole in situ) coal mining enables us to mine difficult coal reserves, deposited under unfavourable geological conditions with higher economical and socio-ecological efficiency than that in conventional coal mining, in view of these the basic principles and concepts of coal mining and coal utilization for energy generation should be reconsidered taking into account the latest achievments in underground coal gasification/combustion, coalbed methane extraction, clean coat technology and advanced developments in environmental engineering. The authors have developed a new concept of ecologically clean and resource saving coal-gas electricity, protected by a patent of Russian Federation (1995). The main principles and technological features of these conceptual technologies are explained hereupon. It should be a break through into a coal mining technology of new generation, which is known as unconventional coal mining technology. Under current global energy policy, transection to the new generation of coal mining technology is inevitable. Now we are standing at the treshhold of the coat's regeneration based on integrated unconventional coal mining and innovative coal fueled electric generation technologies.

Feb 24, 1997

By Jai Ghosh, Aprad E. Torma, Roger Guay

The catalytic effect of ferrous ion in the industrial biohydrometallurgical heap and dump leaching processes is explained. During the bacterial leaching of metal sulfides, ferric ion will partly be hydrolyzed and a variety of sols, gels, amorphous and/ or crystalline mono- and polynuc- lear hydroxo- and sulfato complex species formed, especially by olation and aggregation reactions. There are many problems associated with these iron precipitates especially in the purification of leach solutions. The present study will discuss the iron precipitation reactions; gives kinetic and thermodynamic evaluations of the effect of temperature on pyrite and ferrous iron oxidation; and reports on the tolerance of heavy metal ion concentrations by Thiobacillus ferrooxidans.

Jan 1, 1989

By Pinar Eksert, Hakan Akcin

Investigations show that injuries and fatalities in mining workplaces in developing countries are increasing. In Turkey, the number of workers killed in occupational accidents in the Zonguldak Hard Coal production region per 100,000 tons of coal production is 2.83 in the private sector and 2.03 in the public sector. For this reason, it is important to conduct risk analyses in terms of occupational health and safety and to implement measures quickly. Risks are evaluated with reactive and proactive approaches. Because hazards and events are often unpredictable in high-risk areas such as coal mining, it is not practical or meaningful to plan proactively in advance for every possible situation underground, especially psychosocial risks. However, it is important to develop protective strategies and measures for unexpected events or to take a reactive approach to prevent future incidents or accidents and to identify psychosocial risks. Therefore, reactive risk assessments based on the tactics and strategies of criminology can be conducted and spatiotemporal geographic information system (GIS) techniques can be utilized, enabling managers in mining workplaces to correct assessments.

Oct 1, 2024

By Alejandro Gutiérrez, David Ahues, Paola Merino, Felipe González

A Discrete Elements Method (DEM) study of load movement within a SAG mill 12,192 × 7620 (40′ × 25′) in normal operating conditions is performed. The purpose is to determine how the geometry of the lifters affects the kinetics of the load inside the mill. Specifically, the changes produced by the incorporation of inclined lifters and spiral or helicoidal pulp lifters to the kinetics are evaluated. Four study cases are identified: first, the base case corresponds to a conventional geometry; the second case corresponds to inclined lifters incorporation; third case corresponds to a mill with helicoidal discharge; and the fourth case corresponds to a mill with inclined lifters and helicoidal pulp lifters. To save computational resources, the water that enters the mill has been modeled by varying the coefficient of restitution. The results of a series of experiments are presented to determine how this coefficient varies when having impacts on surfaces with different liquid levels. A comparative analysis is made of the following variables: mean transport speed and material flow, for normal operating conditions. Taking as reference the mill with straight lifters and radial pulp lifters (case 1), the case with the inclined lifters and radial pulp lifters increases the material discharge flow less to 76 mm of size by 5.1%, and this value increases even more when the helicoidal pulp lifters are incorporated reaching a 58.6%. The most significant change is seen in the flow through the grates and the pulp lifters discharge, which can increase substantially improving the operation.

By D. W. Fuerstenau

Experiments using an optically polished Pyrex disk and aqueous dodecylammonium acetate (DAA) films showed that the velocity with which the films recede increases markedly if the runs are repeated at short time intervals, where equilibrium cannot be reattained. This results from DAA molecules being desorbed from the disappearing liquid-air interface and being deposited on the solid-air interface being formed. Controlled experiments with Pyrex particles in a modified Hallimond tube showed a similar increase in flotation rate, again due to excess adsorption of DAA molecules that were transferred to the solid-air interface from the bubble on contact.

Jan 1, 2002

Effective gas management in coal mines, as well as proper ventilation design, is very important for maintaining the safety of underground coal miners. Advances in numerical modeling techniques have enabled evaluations of the coal mining environment using advanced grid designs and computed gas distributions through detailed mathematical models. These models help engineers to see the unseen areas of the mine through visualization of the data and ultimately help improve worker safety. This paper summarizes the modeling efforts conducted by NIOSH in the U.S. and CSIRO in Australia to address various gas management issues encountered in longwall mines. The modeling studies involved two of the most widely used grid-based techniques, namely computational fluid dynamics (CFD) and numerical reservoir modeling. This paper discusses the application of these techniques for gob inertization and gas control for spontaneous combustion, pre-mining degasification of coalbeds, gob gas venthole design and performance evaluation in longwalls, and gas management during development mining.

Jan 1, 2009

By Bryan Ulrich

Rroundtable 2009, a Knight Piésold and Co.-hosted roundtable discussion on mine closure and cover design was held at the Red Lion Inn and Casino in Elko, NV on Feb. 12, 2009. Knight Piésold?s Bryan Ulrich and Steve Boyce, as well as Knight Piésold representatives Cynthia Parnow and Corey Conrad from Denver, CO, and Rick Frechette from the Tucson, AZ office were on hand to help facilitate the discussion. The meeting played host to approximately three-dozen attendees from four states. Attendees included personnel from seven mining properties and attendees from corporate offices. The majority of attendees were people directly involved with environmental work on a day-to-day basis. Other attendees were project managers whose jobs involve some level of environmental focus. The purpose of Roundtable 2009 was to exchange ideas and information pertaining to mine closure and cover design associated with almost any aspect of a mining operation. This type of forum provides a less inhibited format for discussion, when compared with traditional conferences and symposia. In the roundtable format, lively discussions are encouraged. This discussion was the fourth in the series of Elko Roundtable events. Previous roundtables pertained to heap leach pad design, construction and operation; design, construction and operation of tailings storage facilities and site-wide water considerations. The initial subtopics for Roundtable 2009 included:

Jan 1, 2009

By Sadatoshi Ohmori, Karen Shinoda, Nobuharu Isago

Method of tunnel excavation is generally classified such as full-face excavation, bench-cut excavation, diaphragm with center pillar excavation, center drift advancing excavation and so on. These excavation methods should be selected properly in terms of ground condition, the area of tunnel section, the arrangement of construction. Center drift advancing excavation method in mountain tunnel construction, is often applied under quite weak ground condition, prior to the main tunnel widening excavation. Recently, the advancing drift is for the excavation of extreme larger section in main tunnel to confirm the stability of face. In addition, we make advancing deformation occur in drift when the construction was done in poor ground like squeezing and swelling ground, and the force occurred in main tunnel was expected to reduce by the effect of ‘dodging’ for support structure. Mechanical relation between drift and main tunnel has been mainly grasped on past experiences in Japan. However, the characteristic of tunnel enlargement was partially discussed by using the three dimensional analysis and the result was grasped by past experiences on the basis of each tunnel construction. It is considered that the natural ground stress is normally released as the advance displacement, but it was released after the main tunnel widening, causing a displacement and deformation increase. Up to now, the construction practice has shown the reduced displacement during the main tunnel widening excavation by the drift, and the numerical analysis agreed with above observation. However, there is no report found that the displacement and deformation at the time of widening excavation of the main tunnel become larger in case of a drift application. In Kyusyu area, western part of Japan, the northern part of Yoshinomoto tunnel was applied an advancing bench-cutting method for a center drift for the purpose of obtaining the geological information for support selection of the main tunnel in widening excavation. The shape of center drift was a perfect circle with a diameter of 4.0 m or 6.0 m and the same temporary support regardless of the geological situation. As a result, the displacement and deformation of the main tunnel after widening excavation were larger than the section where the center drift was not applied. Furthermore, the displacement and deformation of the main tunnel after its widening excavation was considered larger in the section where the cross-section of the center drift with 4.0 m diameter was applied than one with 6.0 m. Therefore, the center drift with a high rigidity support structure had the effect of suppressing the advancing deformation prior to the main tunnel widening excavation.

Jun 13, 2021

By Brian Khalighi, Massimo Franceschi, Giovanni Giacomin, Gianni Porta

Headrace Tunnels and parts of the Access Adit Tunnels of Kárahnjúkar Hydropower project, KAR-14, in Iceland will be excavated using three full-face Robbins Tunnel Boring Machines (TBM). TBM sizes range from 7.23 to 7.63 meters in diameter and the total headrace tunnel length is approximately 40 km. The crushed rock is transported on conveyor belts to disposal areas near each Adit. The estimated average excavation rate is approximately 25 meters per day per machine. Electricity will begin to flow in April 2007, and the project is scheduled for completion in 2009. This paper is divided into four sections. In the PROJECT OVERVIEW section, a short overview of the scope of the project is presented. In the GEOLOGY section, the geological condition along the tunnel drives is briefly introduced. The TBM DESIGN section discusses the various design criteria and the resulting machine specifications. The paper concludes in the TBM OPERATION section with a case history describing the tunneling operation from start-up to the time of the writing of this paper.

Jan 1, 2005

By Huijun Shao, Qiang Liu, Zhengming Yi

The increase of the proportion of high Al2O3 content iron ore fine in iron and steel enterprises has brought about a series of problems such as the increase of the viscosity of blast furnace slag and the difficulty of the separation of slag and iron. In order to solve this problem, the effect of increasing MgO content on the technical and economic index, the cold strength, and metallurgical properties of high basicity and high-alumina sinter was studied through sinter pot test. Nova400NanoSEM field emission scanning electron microscope was used to analyze sinter microstructure. The experimental results show that when the MgO content fraction in the sinter with high basicity and high aluminum increases from 1.72 to 2.49%, the vertical sintering speed decreases by 4.38mm/min, the utilization coefficient decreases by 0.51t/(m2 h), and the low-temperature reduction degradation index increases by 6.7%. When MgO content in sinter is 2.11%, drum index and reducibility index are the highest, reaching 61.93% and 86.39% respectively. Mg2+ is mainly solid dissolved in the magnetite lattice and replaces Fe2+, up to 3.64%. The generated magnesie-containing magnetite inhibits the phase transition from Fe3O4 to Fe2O3 oxidation process in the sinter cooling process, which reduces the generation of secondary hematite and is conducive to improving the low-temperature reduction degradation performance of sinter.

Jul 4, 2021

By Bahaa Alyosif, Murat Erdemoğlu, Muhammet Kürşat Aydemir, Turan Uysal

The effect of intensive milling on the conversion of microcline ( KAlSi3O8) to potassium chloride (KCl) occurred during the chlorination roasting process for artificial KCl production was investigated. A feldspar ore with 10.89% K2O grade and containing microcline was dry milled by a planetary ball mill for mechanical activation. Milled ore mixed with calcium chloride was roasted at temperatures between 500 and 1000 °C to get the chlorination roasting process. The product was then leached in water to dissolve KCl occurring during the roasting, which will be precipitated from the pregnant leach solution by evaporation. Results showed that potassium recovery from the unmilled ore increased rapidly up to 800 °C, and dramatically decreased at higher temperatures due to the removal of KCl from the furnace by means of evaporation. A potassium recovery of 31.95% was achieved by the unmilled ore, whereas it was 88.43% when 15 min milled ore was roasted at 750 °C. It was concluded that intensive milling caused mechanical activation of microcline to reduce the roasting temperature of the chlorination roasting process.

May 31, 2023

In 1992, the United States economy grew at a rate of 2%. The Gross Domestic Product rose to $5,946 billion. With 257 million people - 635,000 in mining including petroleum - the United States has more than 100 million dwelling units and more than 190 million licensed motor vehicles. New private housing starts rose I 1 % to 1.2 million units. New car production rose 4% to 5.7 million units. Truck and bus production rose 20% to 4 million units. The rate of inflation was 3.5% and the prime rate of interest was 6.25%. The Producer Price Index (1982 =100) was relatively unchanged from 1991 as follows: fuels and related products and power 80, metals and metal products 119, chemicals and allied products 126 and nonmetallic mineral products 117. Energy Imports of crude and refined petroleum, costing $50 billion, rose 3% to 455 Mm3 (2.9 billion bbl). Domestic petroleum production fell 1 % to 582 Mm3 (3.5 billion bbl). Petroleum supplied about 41 % of US energy, natural gas 24% and coal 23%. Coal production, 60% from surface operations, rose 1 % to 914 Mt (1 billion st). About 78% was used to generate electricity and 3% was coked. Exports valued at $4 billion included 57 Mt (63 million st) of metallurgical coal and 39 Mt (43 million st) of steam coal. Ura¬nium mining, including recovery from phosphates, fell 18% to 3 kt (3300 st) U308.

Jan 1, 1993

By Raymond W. Henn

The 31th annual short course ?Grouting Fundamentals and Current Practice? was held at the Colorado School of Mines, in Golden, CO June 7-11, 2010. The field demonstration portion of the course was conducted June 10 at wlh Construction Co.?s yard in Denver, CO. The full-scale field demonstration presents many types of drilling and grouting equipment in operation as well as numerous grouting methods performed under various field conditions.

Jan 1, 2010

By Pramod C. Thakur

Coal is a major source of energy in the world today and will, undoubtedly, continue to be so for the next few centuries. Naturally, a great number of studies has been made of its physical and chemical properties. Unfortunately, the work on technical properties which influence the mining of coal and the consequent yield of inflammable gases and respirable dust particles has not progressed at a comparable pace. Coal is a brittle material. Irrespective of the mechanism of breaking coal, some dust is always produced. In mining parlance dust is defined as solid particle, smaller than 100 microns (micron = 10-6 meter), in size Coal dust, when raised into a cloud, creates two well known hazards in mines, namely, the coal dust explosion and Coal Workers' Pneumoconiosis (CMP). The latter is, perhaps, the greatest environmental hazard in U.S. coal mines today. In this context it is not only natural but also necessary to investigate the proneness of a coal seam to respirable dust production. It has been established that the amount of dust produced is a function of two groups of variables (1), (2), viz. (1) Material dependent variables, e.g., moisture content, compressive strength, hardness, etc. (ii) Breaking mechanism dependent variables, e.g., type of machine, depth of cut, etc.

Jan 1, 1973

By Wayne C. Smith

Both water pollution and proposed solid waste disposal regulations have a definite effect on the copper leaching industry and some of the major factors affecting the industry are discussed in this paper. New developments of the NDPS are discussed with emphasis on the "toxic" or priority pollutants and EPA's philosophy on the control of these pollutants, The protection of groundwater is the prime aim of RCRA through solid/hazardous waste management. Some of the major elements of the RCA regulations that will affect the copper leaching industry are discussed.

Jan 1, 1980