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By Charles H. Grant

Blast design methods generally deal with end points or limits of design such as spacing, burden, stemming depth, etc. Even cratering design deals with limits defined as a function of energy decay to a limit. Although this crater method provides a better method than trial and error judgment it does not take into consideration the distribution of energy throughout the material to be blasted. This paper deals with a method of examining this distribution with the aid of a computer and how changes in blast design affect this distribution. First I would like to explain the equation used to develop the energy summations throughout the blast. As shown in Figure I a series of drill holes are drilled to various depths starting by placing the explosive charge on the surface and then at various depths until a sufficient depth of hole is reached to exceed the ability of the explosive energy effect to reach the surface of the ground. All volumes of explosive are the same, all holes contain the same explosive and the drill hole diameter is the same.

Jan 1, 1980

By K. Takahashi

The methyl stretching vibrations for a series of normal and iso xanthates were determined using an infrared spectrophotometer, and the results were compared with the published information on the corresponding alcohols. The frequency shifts of methyl stretching vibrations may be attributed to the inductive effect of polar groups. The hydrogens in the shorter chain alkyl groups are somewhat polar and can be expected to interact with water molecules by hydrogen bonding. Contact angle, surface tension lowering, and solubility appear to be related to the induced polarity of the alkyl groups.

Jan 1, 1968

By U. S. Sawant

During the last few years, Process Machinery Division, Rexnord, has conducted extensive research on the effects of cone crusher variables such as speed, throw and cavity design on the productivity of the crushers. Simultaneously, Rexnord's engineers have developed advanced design and testing techniques and criteria that assure efficient and reliable crusher designs. The combination of these two has resulted in a design of the 2390 Omnicone (1000 hp) crusher which fits on an existing 7 ft. Symons foundation and yet is capable of producing twice the tonnage compared to our 7 ft. super heavy duty (500 hp) crusher. Both speed and throw can be varied to give a wide application flexibility from making twice the tonnage to the finest product. The 2390 Omnicone also incorporates innovative features such as full balance, cavity clearing, adjusting under load with automation capability, maintenance-free seals, one head for all cavities, ease of maintenance and servicing, etc.

Jan 1, 1987

By R. A. Lowe

Smectite is a common impurity in the kaolins of Georgia. This impurity is harmful to the low-shear rheology of kaolin slurries in concentrations as low as a few weight percent. The deleterious effect of smectite on the low-shear rheology is due to the swelling of the mineral. Montmorillonite containing clays were treated to precipitate a compact brucite layer {Mg(OH)2} in the interlayer region of the expandable layer silicate mineral. This treatment forms a hydroxy-Mg-montmorillonite with characteristics similar to chlorite. This treatment effectively reduces the swelling capacity of the mineral and improves the rheological properties of kaolin slurries contaminated with smectite impurities.

Jan 1, 1999

By S. Zamna, M. E. Defoe, Franklin T. Davis, Earl Rau, Yarroll. Warren H., Paul D. Chamberlin

This section contains a description of the ore processing methods of the walled industrial minerals that are not described in major sections of the book. Table I contains the production figures for each of these commodities in the United States and the world. Specifications for concentrates or final mineral product are also summarized as well as prim for them at the time the section was written. In each chapter an attempt has been made to provide the reader with information on the common commercial mineral or minerals involved with the commodity, some of the uses. the processes used to recover and concentrate the minerals, as well as geographical areas where these process are utilized.

Jan 1, 1985

By Gregor de Ratmiroff

Field prospecting for bauxite in Venezuela has had a long but interrupted history having till now oferred but evidence of occurrences. The Venezuelan Government, trough the Corporación Venezolana de Guayana (C.V.G.), in 1974, formalized a major effort in prospection for bauxite in the Shield area and the Orinoco Delta in orden to establish the possibility of raw material supply to an upcoming and expanding aluminium industry. The Corporation, in turn, created and delegated to the Division of Geological Stu- dies, the formulation of the necessary infrastructure and execution of work in orden to determine the existence of economically exploitable bauxite deposits.

Jan 1, 1979

By A. G. Royle

Although these exhibit similar structures overall, there are more acute valuation problems in alluvials. Most of this description will therefore be about alluvials with comments on bedded vis-a- vis alluvial deposits where necessary. Although geological comments refer mainly to lateritic deposits the method of valuation described applies to all bedded deposits, e. g. coal, limestone, phosphate. In general, the more a deposit suffers alteration during or after its formation and the more the sampling process disturbs its material, the greater the difficulties of valuation. Emphasis is laid on structure, as in any kind of deposit valuation cannot proceed until its structures are understood. Not all the structures found in alluvials will occur in bedded deposits, of course.

Jan 1, 1982

Copper cathode and Uranium Oxide production at WMC (Olympic Dam Corporation) Pty. Ltd. involves processing leach liquors through a copper solvent extraction plant followed by a uranium solvent extraction plant. This paper discusses the processing problems, metallurgical testwork and circuit changes made due to contamination of amine in the oxime circuit and vice versa.

Jan 1, 1996

By Mr. Peter J. Huck

Recent research has developed procedural control and geophysical test methods that can greatly enhance quality control in rock grouting. Confidence that design objectives will be made In construction requires that grout monitoring efforts be carefully designed and integrated into the overall project. Parameters that should be monitored are identified and documentation/review procedures that permit effective evaluation of the grouting effort are discussed.

Jan 1, 1980

By Nicholas Chlumecky

A practical method is described for determining or checking whether underground supports such as props, posts and mechanized longwall supports have bearing areas of proper size in relation to the type of ground or floor strata on which they are standing, It is felt that this information provides an approach to eliminate, as much as possible, a potential grave source of error during the selection of roof supports. This would also affect the choice of costly mechanized longwall equipment where it is possible that the size of the bearing area is not as carefully determined as, for instance, the design strength of structural components.

Jan 1, 1967

By M. T. Ityokumbul

Experiments have been carried out to determine the efficacy of bubble column flocculation. An acid-base neutralization method was used to determine the mixing time in a 0.064 m x l.5 m bubble column equipped with a Mott porous sparger. The mixing times decreased as the tracer injection point approached the gas sparger. Preliminary flocculation experiments on two clay samples were carried out. The effects of frother addition and air flow rate are presented and discussed.

Jan 1, 1998

By William Lodding

That grinding may change a crystalline material both in a physical and in a chemical sense has been shown by a number of authors in recent years. Thus Mackenzie (1) and Bartha (2) reported the effects of careful grinding on muscovite, quartz, gypsum, dolomite, etc. Increase in specific surface produced by grinding implies increase in total energy of a system. Newly produced surfaces are chemically more reactive; dislocations may be introduced during grinding, and existing strain may be released by the same process, as shown by Holt et el. (3) All these changes are easily detected by thermal analysis, but it is not easy to separate the multiplicity of effects registered and to arrive at quantitative interpretations. This paper is an attempt to analyze by the use of thermal analysis some effects produced in grinding. In differential thermal analysis (DTA) one measures all thermal changes occurring in a substance during heating or cooling. Chemical changes, such as decompositions, synthesis, oxidation, reduction, etc., and physical changes such as phase transformations, changes in specific surface and in thermal conductivity, strain release, etc. By thermo gradmetric analysis (TGA) on the other hand only chemical changes involving weight loss or gain are recorded. Similarly gas evolution analysis (GEA) will register only reactions involving gas evolution, including water vapor, and oxidation-reduction. By performing two or all three of these thermal methods of thermal analysis simultaneously and on the same specimen one can separate the different effects registered and by difference evaluate their magnitude.

Jan 1, 1966

By J. D. Carson

A 0.60 km2 (150 acre) wetland was reclaimed by Agrico Mining Company as part of a 1.48 km2 (366 acre) reclamation program in southwest Polk County, Florida approved by the Florida Department of Natural Resources. The upland portion of the area provides watershed for the wetland site which overflows into the flood plain of Payne Creek. Construction of the wetland was designed to provide conditions favorable for a diversity of habitats, as well as retention time for surface runoff waters. A variety of revegetation methods, including innoculation with muck from unmined wetland depressions, have produced encouraging results with both woody and herbaceous species.

Jan 1, 1983

By Louis I. Briggs

Evaporite rocks, salts of the more soluble ions in seawater, are deposited when seawater becomes concentrated by excess evaporation in marginal basins having restricted circulation with the open sea. The simple conceptual model of an evaporite basin (Figure 1) has a single inlet connecting the basin to the open ocean, the restriction to open circulation being caused by a bar or reef near the mouth of the inlet. As the oceanic water flows from the inlet into the basin it tends to form a thin layer of brine that spreads out over the surface of the basin brine, and as it does so, the salt concentration In the surface layer gradually increases owing to continued evaporation of the water. When the solubility products of the salts in the surface layer are exceeded, the salts precipitate and settle to the bottom of the basin, The order of precipitation follows their order of least solubility. Normally the carbonates separate first, followed by the sulfates and chlorides and the more complex double salts. In nature there is considerable overlap in their ranges of precipitation. The water flow in the basin, also shown schematically in Figure 1, diverges from the inlet essentially perpendicular to the lines of' equal salinity in the surface brine. The distribution of salts deposited in such a model will parallel the isosalinity lines, being arcuate and concave toward the inlet (1)

Jan 1, 1967

By Gregory E. Korbin

The effectiveness of pre-reinforcement as an immediate stabilization measure as well as its contribution to the permanent stabilization of a tunnel were studied through the use of physical (Figure 1) and numerical models (1). Physical models were designed for the investigation of two pre-reinforcement systems: first, reinforcing far ahead of the main excavation (Figure 2); second, spiling reinforcement ahead of the face (Figure 3). In both cases, the use of reinforcement was responsible for permanently stabilizing an otherwise unstable opening. Data from the physical models were used to calibrate a numerical model from which additional information on long term behavior, methods to account for the capacity of a pre-reinforcement system, and the mechanisms involved were ascertained. These studies indicated that pre-reinforcement can stabilize a rock mass effectively as it reduces deformations and thereby deterioration due to strain softening, provides rock mass confinement leading to increased available strength, and maintains rock arch continuity allowing for increased tangential stress in the immediate vicinity of the opening. Field studies verified the capacity of spiling reinforcement to restrain initial deformations.

Jan 1, 1976

By Eugene E. Hively

The Tower Kill is a vertical "stirred" ball/pebble mill recently introduced in the Western Hemisphere. This device offers a significant power savings on wet fine grinding applications when compared to conventional tumbling mills. This paper describes the laboratory application of this mill wet grinding hydrated alumina to products of 50 percent passing 2 to 6 microns.

Jan 1, 1983

By John T. Awald

The Bradshaw Mountains of west-central Arizona cover an area of 1600 square miles and contain numerous old mines and prospects. The area has been geochemically sampled on a reconnaissance basis to relate mineralized areas to regional structure and rock types. Copper analyses of stream sediments have been classified and contoured to show the distribution of low background, high background, and low, intermediate and highly anomalous areas. Contoured results are compared to geology and known mines. Several prospecting areas are indicated.

Jan 1, 1970

By R. W. Brann, R. C. Freas

Franklin Industrial Minerals operates several mines/quarries, including two room and pillar underground mines. Both of these mines are operated as multiple level room and pillar including heading and bench operations on one or both of the levels. This paper focuses on Franklin’s Crab Orchard, Tennessee mine, which produces both high purity chemical grade limestone and crushed stone for construction applications. The high purity chemical specifications for the chemical grade limestone and filler/extender applications are inconsistent with the non-chemical rock being produced to supply the crushed stone market. As a consequence Franklin has developed a unique mine plan and operation to maintain both product balance and a safe and stable working environment.

Jan 1, 2003

By Ronald E. Yarbrough

As a result of concern for the citizens of the State of Illinois who owned structures above underground mine workings, the Illinois State Legislature passed House Bill 158 in 1978. This bill amends the Illinois lnsurance Code and creates the Mine Subsidence Reinsurance Fund which is an insurance pool that is to receive a state appropriation of $500,000 as "start-up" money. One hundred thousand dollars has been paid to the fund as of October, 1982. The Fund is to return this appropriation to the State and is to remain self-supporting from premiums. The Fund utilized a pre-existing institution, which also was an insurance pool, the "Fair Plan Facility" and its governing Board, consisting primarily of insurance executives, to administer the program. The Mine Subsidence lnsurance Act went into effect October 1, 1979, and the bill provides that property owners in the State of Illinois may purchase up to $50,000 of mine subsidence insurance which is attached to their fire insurance policy. The deductible is normally 2%, but cannot be less than $250 or more than $500. The annual rate structure for residential structures in 1981 for $50,000 coverage is $10 (frame), and $12 (masonry). The rate structure for commercial buildings is based on the value of the building and the rates for $50,000 maximum coverage is adjusted upward. The insurance was mandated by the State Department of lnsurance and rolled onto the insurance policies of the homeowners in 34 counties which had been recognized as having sufficient exposure to subsidence damage to be covered by the Act. One percent or more of the land surface is undermined in each of the 34 counties. In the other counties undermined in the State of Illinois, insurance is available to the homeowner upon request to the private insurance carrier.

Jan 1, 1982

By David D. Rabb

Leaching or solution mining, a relatively simple and economical process for beneficiating metallic ores, is likely to find increasing application in the treatment of low-grade ores that are impractical to mine by any other means. This process may be carried out in two different ways: 1. Dump leaching, where the ore is moved from its original location to be leached at another site. 2. In situ leaching, where the ore is leached in place by introducing the leach solution at the top, letting it flow down through the ore under gravity, and then recovering it plus the dissolved metals it contains.

Jan 1, 1969