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By David D. Gallagher

Customer demand for greater efficiency and reduced operational costs on modern overland conveyors has focused attention on the conveyor belt's rolling resistance properties. Studies have indicated as much as 60% of the power losses on a long horizontal conveyor can be attributed to the indentation of the pulley cover rubber as it passes over idlers. This paper will compare tan delta values of different compounds with large scale rolling resistance test data from the University of Hannover. Results will then be compared to actual power consumption data gathered on several long overland conveyors using identical belt construction except with different pulley cover compounds. Concluding comments will be made indicating substantial operating cost differences based on the rolling resistance of the cover compound.

Jan 1, 2000

By C. DeRossett, K. F. Unrug

Sedimentary rock fractures commonly occur in the vicinity of outcrops. Mine highwalls and highway cuts provide excellent views of these near-surface joint systems. This paper explains the origin, characterization, distribution and extent of the these joint systems with reference to the lithologic composition of the rocks. The practical implications of these joint systems on the operation of a mine are described. Included are discussions of the discontinuous deformation that results from surface subsidence, the stability of mine portals and near-outcrop underground operations, and the stability of highwalls when using highwall miners and strip operations. Some design procedures are recommended to minimize the problems encountered within mining areas having intense joint systems.

Jan 1, 1996

By D. W. Hendrickson

Cleveland-Cliffs views the mining process as ex- tending from mine planning to cargo loading including auxiliary systems such as materials handling and plant utilities. Process automation is recognized as an area that can provide significant improvement opportunities with less capital requirement than major flowsheet modifications. This article discusses the development and results of a strategy to allow and promote implementation of process-automation improvements at individual mines based on their economic priorities, taking advantage of common systems and concepts for use at multiple mines where practical. Specific process-control upgrade projects at Hibbing Taconite Co. and the Empire Mine are reviewed.

Jan 1, 1998

By M. Ericsson

The extractive industries consist of five major sectors: - Mining equipment and services - Dimensional stone - Industrial minerals - Aggregates - Metal mining These industries produce some finished goods but mostly semi-finished products as they feed into other industrial sectors: Basic metals, fabricated metals, construction, chemicals, dyes and pigments, inorganic chemicals, fertilizers, rubber and plastics and non-metallic mineral products. These are the major down-stream industries in this study. Taken together with the extractive industries they form the mineral resource based cluster. The mineral resource based cluster is a substantial part of the Finnish economy: It employs 211 000 persons, 39% of the number of employees in industry. The cluster?s exports account for 20% of industry exports. Value added is 34% of total value added in industry. Investments reach 35% of total industry investments.

Jan 1, 2003

By C. A. Wiggins, J. M. Kennedy

The Benbrook Connection tunnel forms approximately 6,666 m (19,560 ft) of17,678 m (58,000 ft) of raw water pipeline connecting Lake Benbrook with the Rolling Hills Water Treatment Plant. This connection is designed to minimize costs to the owners, the Tarrant Regional Water District, for providing raw water to its’ various clients. The geological formations through which the tunnel passes and the design requirements resulted in some-what unique applications of initial ground support systems which were modified by the con-tractor to optimize the mining operations. The pipe sections, fabricated in 12 m (40 ft) sections, are concrete lined and coated steel pipe. Construction of the work shaft and tail tunnel was also modified to suit the contractors methods. A Lovat universal TBM was chosen to excavate through the various rock types. The pipe sections will be transported using beam carriers.

Jan 1, 1997

By T. E. Garnar

Heavy mineral mining has been a small, but important Florida industry over the past sixty years. Early geologic history of each deposit is similar up to point of deposition in alluvium, deltaic sediments, or along shorelines. Later geological development through reworking and concentration is different for each deposit. The Trail Ridge deposit was formed by reworking Citronelle sediments of the Lake Wales ridge. Post depositional leaching of iron from ilmenite makes Trail Ridge an important source of titanium minerals for TiO2 pigment manufacture. Research leading to the separation and sale of by-product heavy minerals from Florida deposits has been important in maximizing profitability. Advances in mineral dressing technology will lead to future mining of lower grade reserves. Future needs for heavy minerals seem certain to expand, with increased activity in exploration and development of mining operations.

Jan 1, 1972

By John Wiebmer

Several industry trends are putting new demands on surface mining equipment. This is true both on the “hard” side of the equipment business - the research and product development programs, and on the “soft” side - the business processes, human resources and competitive strategies. This article describes seven key industry trends and the impact each is having on surface mining equipment suppliers. 1. Globalization Earth-spanning technologies are shrinking the world into an economic village, causing corporations to think and plan on a global scale. This “globalization” is one of the great buzzwords of the 1990s, meaning precisely whatever the user says it means. In this case, let us take it to mean that political boundaries arc less restrictive than in the past, permitting mining companies new freedom to roam the globe for ore bodies. Evolving out of this are global mining houses that have ownership and management interests in labyrinthian webs of mines spanning the world. There are several impacts on surface mining equipment suppliers.

Jan 1, 1994

By V. L. Jr. Davis, F. L. Stanley, P. J. Bethell

Fwe 3 m (10 ft) diameter Microcel™ flotation columns were installed at Clinchfield Coal Company's Middle Fork preparation facility in order to reduce product ash and increase recovery and plant capacity. The Middle Fork facility is utilized for the recovery of fine coal from a feed stream that consists primarily of 1 .5 mm x 0 material. The columns replaced conventional flotation cells for the treatment of the minus 150 pm fraction while spirals are used to upgrade the plus 150 pm material in the plant feed. The addition of the column flotation circuit resulted in an increase in plant capacity in excess of 20 percent while reducing the flotation product ash content by approximately 7 percentage points. Flotation circuit combustible recovery was increased by 17 percentage points. This paper discusses circuit design, commissioning, and sparging system design. Circuit instrumentation, level control, reagent system control, performance comparisons with conventional flotation, and general operating procedures are also discussed.

Jan 1, 1995

By Gary D. Babbitt

Facing an orchestrated assault from the anti-mining lobby and its congressional allies, the Mining Law of 1872 may soon be either dramatically changed or even repealed. In 1989, Sen. Dale Bumpers (D-AK) introduced Senate Bill 1126 entitled the "Mining Law of 1989." It has been through several hearings and is still in the Senate Committee on Energy and Natural Resources, where Sen. Bumpers is the number two ranking Democrat. In the House, Rep. Nick J. Rahall (D-WV) introduced the "Mineral Development and Exploration Act of 1990," HR 3866. This bill is in the House Committee on Interior and Insu¬lar Affairs. (The numbers on these bills, and perhaps some of their language, will be changed when they are reintroduced in early 1991. However, their substance is expected to remain substantially unchanged. Bill numbers here refer to legislation as it was numbered in the 1990 Congress.) In the eyes of its supporters, Bumpers' S 1126 appears to be more complete and has the inside track over the Rahall bill. Bumpers' bill includes provisions for royalties, bonding and reclamation. The Rahall bill is criticized by opponents of the Mining Law for its failure to include a royalty provision and for not having specific bonding and reclamation provisions.

Jan 1, 1991

By Hassan Madani, A. Malek Mohammadi

Dorreh barite mine located in the central part of Iran is one of the largest barite mines, in the country. The mine is subdivided into three blocks, which are called block 1,2,3 according the barite quality. In the central part of each block, a heavily concentrated grid of exploratory drill holes have been drilled and the reserves of area was calculated based on these holes, some years ago. It was decided to compute the reserve of the area by geostatistical methods, in the form of an M.Sc. project. In order to study the area, three regionalized variables including density, thickness and density-thickness (accumulation) was studied and the spherical variograms were fitted to these variables. These models were evaluated by cross-validation method. The optimized block size was chosen in order to compute the reserves by kriging method. The reserves of explored parts of each block of mine was calculated and the results were extended to the whole area of the blocks. The reserve of the explored parts and the total reserve of the area were calculated to be 96,000t and 1,670,000t respectively.

Jan 1, 1996

By David M. Mchaina, Michel Grenier, Stephen G. Hardcastle

An airborne dust survey was conducted at the Arthur W. White mine of Dickenson Mines Limited by CANMET/MRL and Dickenson Mines Limited Staff in April 1990 for the purpose of evaluating environmental conditions underground and in the surface mining plants. The survey was designed to measure respirable silica, total arsenic and lead concentrations at several workplaces. In addition, settled dust and rock samples were collected from workplaces and analysed for total arsenic content. More importantly, arsenic exposure data were needed to evaluate the impact of Ontario Regulation 176/86 as amended by Ontario Regulation 23/87. A total of 165 area and personal air filter samples were collected during the study. Of these, 85, 67 and 13 samples were for arsenic, silica and lead respectively. Sampling aid analyses were performed according to the Ontario Ministry of Labour Regulations. More than 90% of the workplaces sampled for respirable silica, total arsenic and lead were below the Ontario Ministry of Labour Regulations; and 10% of the workplaces sampled for arsenic shaved concentrations above the Threshold Limit value (TLV) proposed in the Ontario Regulation 176/86 as amended by Ontario Regulation 23/87. These results were used to identify occupations and/or workplaces where more sampling and control measures were required respirable silica, total arsenic and lead. This paper describes the results of the dust sampling program conducted at Dickenson Mines Limited.

Jan 1, 1991

By A. C. Ruckman, Allen G. D., G. H. Beckwith

This paper describes the design and operational features of several asphaltic concrete gold heap leach pads which have been constructed in the United States over the past 12 years.

Jan 1, 1988

By A. C. Lyons

The presentation describes the history, preliminary report, site investigation, including examination of old records, design of tunnel including choice of levels, alternative linings and working sites, the preliminary contract involving shaft sinking on the site of the Tower Block; design modifications, the main contract, including shaft sinking, ground treatment, compressed air installation, machine tunnelling, tunnelling enlargements for chambers, waterproofing and equipment.

Jan 1, 1981

By J. R. Larsen

The perlite review arrived too late to appear in the June issue. Worldwide production of perlite in 1991 was estimated to be 1.7 Mt (1.9 million st). Events in Eastern Europe and the former Soviet Union caused reporting of production, consumption and reserves from those regions to cease. The US Bureau of Mines reported data only from the US and Greece. Together, the two countries produced about 701 kt (773,000 st), down from 739 kt (815,000 st) in 1990. US production of perlite amounted to about 547 kt (603,000 st) last year. US production was supplied by 10 companies operating 11 mines in seven western states. There are 74 plants producing expanded perlite in 33 states and in Canada. All the companies engaged in mining perlite are also expanding it.

Jan 1, 1992

By B. J. Swenty, J. L. Hubbard, R. L. Peyton

Based on the results of the National Program of Inspection of Nonfederal Dams conducted by the US Army Corps of Engineers during 1977-1981, Missouri was found to have the highest number of "unsafe" dams in the nation. Many of the dams classified as unsafe in Missouri were tailings dams.

Jan 1, 1987

By D. S. Choi

This paper presents the results of geomechanics work applied to the longwall operation. The mining method was successfully adapted to US mining conditions resulting in an improvement in safety and productivity. The paper deals with various geomechanics problems associated with geologic and mining conditions.

Jan 1, 1987

By S. J. Porter, M. T. McRae

The Melbourne City Link project includes two three-lane highway tunnels, 1.6 and 3.4km long, respectively, which are both approximately 16 meters wide and 9 meters high. The tunnels will be excavated through interbedded, moderately to highly jointed siltstones and sandstones of the Silurian Age Melbourne Mudstone formation over the major parts of their lengths. The strength of the intact rock varies from less than 5 MPa to greater than 70 MPa. Based on the available information regarding the performance of large span tunnels in weak rock, it was considered that the commonly applied empirical design guidelines for tunnel support, based on rock mass classification systems, should be augmented by more explicit design methods. The support design was, therefore, validated by analytical procedures, including numerical analyses, which are described in this paper.

Jan 1, 1997

By H. J. Zhang, W. Wui

With the adoption of market-oriented economic policies, Chinese non-ferrous metals industry has gained remarkable progress. The continuously increasing domestic demand for non-ferrous metals, however, calls for more import of raw materials in short supply, such as copper concentrate and bauxite. As an alternative for balancing the shortage and assurance of more stable mineral supply, direct investment in oversea mining project has come to the agenda. This paper discusses the computer-assisted method used for evaluation and comparison of potential mining projects.

Jan 1, 1996

By John N. Murphy, Edward F. Fries

The availability of fast, low-cost computer hardware and advanced software is opening new opportunities for minerals extraction and processing. Programmable Logic Controllers (PLC's) are currently used extensively in the minerals industries; this paper looks beyond PLC's and that vintage of “computer control”--it looks toward what the authors see as new in the next five years. Topics covered include expert systems, neural networks, intelligent signal processing, and hierarchical controllers as applied to mining and mineral processing operations.

Jan 1, 1993

By G. V. Krishna Roa, G. Vijaya Kumar

One of the main objectives while planning ventilation systems for mines with multiple fans is minimization of the total airpower consumption of the mine. Solution of this problem by conventional ventilation network analysis programs is tedious and time consuming, and may not yield optimum results in all the cases. The paper presents an algorithm for solving multiple fan networks by finding optimum combination of fan operating points for required airflow distribution in the ventilation system.

Jan 1, 1995