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By M. Lastra, A. Cruz, J. Menacho

The use of phosphates was studied as a way of purifying acidic copper leach solutions for direct electrowinning. The addition of 2.5 gpl phosphorus to plant solutions originally containing 6.25 gpl Fe (III) at pH 2 0 reduced the iron concentration by one half. Under identical conditions, but without phosphorous additions, the iron concentration was reduced by less than 1 gpl. Any residual phosphorous had no undesirable impact on electrowinning. The concentration ratio of Fe (III) to phosphorous which provides maximum iron elimination was determined. Higher ratios bring about a redissolution of the iron precipitate. Several ways of controlling iron with phosphates are discussed. These take advantages of more rapid and complete iron precipitation at lower pH levels.

Jan 1, 1980

By Kevin M. O’Connor

Examples are presented in which Time Domain Reflectometry (TDR) was employed to locate deformation in rock masses induced by mining. The first example involved monitoring the propogation of overburden fractures above a longwall coal panel and the second example involved the use of TDR to monitor rock mass deformation in the vicinity of a strip mine highwall. Rock mass deformation, strata separation and large block movement generated strains and failure along coaxial cables which were installed in drill holes and the TDR reflections generated by these strains and failures were monitored. Analysis of field data and a preliminary laboratory test indicate that it may be possible not only to locate rock mass movements but also to quantify these movements with TDR data.

Jan 1, 1984

By Andrew W. Jenike

An efficient storage plant contains a known available volume of bulk solid, and feeds it at the required time, the prescribed rate and without degradation of the product. A storage bin may also perform other functions, such as blending different grades, degasifying aerated powders and isolating different gaseous media. A contact bed of particles flowing by gravity in counter-current with a gas or liquid may be used as a continuous reactor. In order to design an efficient storage plant or contact-bed reactor, it is necessary to be aware of the problems which can arise in flow and storage. The typical problems are no flow, erratic flow, flushing, insufficient flow, lack of designed capacity, segregation, degradation of the product and level control.

Jan 5, 1968

By J. E. Campbell, G. D. Calkins, N. M. Ewbank, M. Pobereskin, A. Wesner

GRINDING for size reduction affects the economics of many processes and products. It is essential as the first step in many industrial processes and is also a finishing step for materials with properties depending on particle size, such as talc, cement, and silica sand. Intermediate and fine grinding are vital operations in the U. S. cement industry, which is producing more than 250 million bbl of cement per year.1 Wear of the grinding media is a large part of the grinding operation cost. Problems encountered in grinding cement are so complex that evaluation of efficiency and economy of grinding media is difficult.2 It has been especially difficult to evaluate the relative effectiveness of different types of balls because there are no good testing techniques.

Jan 12, 1957

By M. L. Jeremic

Mining practice and underground studies show that, besides mining stresses, lateral tectonic stress also influences roadway stability. Roadways perpendicular to the direction of major lateral stress experience the majority of roof falls, accelerated floor heave, and extrusion of coal ribs into openings. They have the most severe deformations and their maintenance is difficult. Roadways parallel to the major lateral stress exhibit roof sagging and bed separation, moderate though sometimes uneven floor heave, and slabbing of coal ribs into openings. Roadways oblique to lateral stress have, to a certain degree, self-supporting roofs, uniform floor heave, and limited sloughing of coal ribs into openings. The optimal orientation of roadways is, therefore, oblique to the lateral stress direction with fewer crosscuts between them.

Jan 1, 1982

By Roger K. Clifford, Gary W. Hudiburgh

The amine flotation of feldspar from a magnetite concentrate produced at a domestic concentrator was investigated using zeta potential measurements, Hallimond tube flotation tests, and laboratory-scale flotation tests. The point of zero charge of six feldspars (microcline, orthoclase, albite, anorthite, anorthoclase, and oligoclase) range from pH 1.4 to 2.5. Hallimond tube flotation tests using amine flotation reagents were performed on these feldspars and on gangue material (quartz, albite, and microcline) from the magnetite concentrating plant. Laboratory-scale (623 g and 2500 g) flotation tests were performed on the magnetite concentrate to float the feldspar. The effects of three different collectors, two levels of collector concentration, three pH levels, starch, HF acid and regrind were investigated.

Jan 1, 1977

By Lawrence W. Teufel

An anelastic strain recovery technique is presented as a method of determining the directions and ratio of the maximum and minimum horizontal in-situ stresses from oriented cores from deep wells. Predictions of hydraulic fracture azimuth inferred from principal stress directions determined from both elastic and time-dependent (anelastic) strain relaxation measurements of volcanic tuff are consistent with the observed orientations of hydraulic fractures produced in simulation and mineback experiments, underground at the Nevada Test Site. In addition, anelastic strain recovery measurements on oriented cores of shale and sandstone from well depths of about 1680 meters show consistent relaxation directions of the principal horizontal strains and have enabled a prediction of the principal horizontal stress directions and hydraulic fracture azimuth.

Jan 1, 1982

By Shosei Serata

Conventional roof bolting may be giving ground to a new technique that utilizes only the ground itself to stabilize mine openings. This newly developed stress control technique (SCT) has initially been used in sedimentary ore bodies that are both overlain and underlain by weak strata. The technique is also suited to the design of production panels and main entry systems, and is readily adaptable to room and pillar as well as total- extraction mining, including both shortwall and longwall coal mining. In applications where the technique has been used, the requirements for roof bolting and floor renewal were virtually eliminated. The SCT comprises three basic methods and covers a wide range of problems associated with failing roofs and heaving floors in underground mines (see Table 1).

Jan 5, 1976

By Charles J. Speake, Dennis R. Haley, Thomas E. Finch

The tremendous interest in development of surface- mineable coal throughout the western US will bring with it a requirement for many manhours spent in mine planning and equipment selection. One problem in particular that engineers face during the planning stage is that of selecting a dragline with the proper reach capability. Reach, expressed in terms of operating radius and effective spoil radius, can be a major problem when mining deeper than originally planned, and aside from production requirements, the ability of a particular dragline to spoil across a strip is essential. Determination of dragline reach needed for a multiple-seam western coal operation can be simplified by use of an equation derived below that eliminates the need for tedious and repetitive calculations.

Jan 5, 1977

By J. M. Karpinski, F. P. White, R. L. Stone

By means of laboratory balling tests and a procedure for determining bentonite concentration in a green ball, the present study revealed that the bentonite savings by mulling concentrate and bentonite prior to balling was sufficient to warrant installation of a full-size unit in a pellet plant. On the basis of this work, a muller was put on stream at Bethlehem Steel Corp.'s Cornwall pellet plant in June 1969, and has operated continuously since then. Plant tests showed that the use of the muller resulted in bentonite savings of about 50% without any loss of green, dry, and fired ball quality. Virtually no maintenance problems have been encountered. This information is important to future pelletizing operations both from the standpoint of product quality and economics.

Jan 1, 1972

US 4,183,899 - Flow process for chlorinating ilmenite. A laminar flow of a mixture of ore, a carbonaceous reductant, and chlorine gas or other chlorinating agent is passed through a reaction zone maintained at a temperature of 1350 to 1950°C and a product stream Including titanium tetrachloride is withdrawn from the zone. The atomic ratio of carbon to oxygen in the feed mixture is greater than 1:1, and the molar ratio of chlorine to titanium solids In the product stream is between about 0 5.1 and 2:l. Titanium chlorides and metallic iron are recovered separately from the product stream. J.P. Bonsack, assigned to SCM Corp, Jan. 15, 1980 21 pp. (423-79). Filed. 3-10-78 (885,442).

Jan 1, 1982

By A. Sainato, E. Baker, J. Cervik

In Europe, water infusion is used widely to reduce generation of respirable dust during mining. Its use in the US is limited to a few plow operations in the deeper parts of the Pocahontas No. 3 Coalbed. The technology for infusing water into retreating longwalls is described and results of a recent Bureau test in the Lower Sunnyside Coalbed demonstrated dust reductions ranging from 47% to 64%. Because water infusion increases moisture content of the coalbed, face air velocities in excess of 2.5 m/s (500 fpm) are possible, further diluting dust levels before dust entrainment occurs. An economic analysis shows a 23% reduction in operating costs when coal production is increased by changing from unidirectional to bidirectional mining with water infusion.

Jan 1, 1986

By H. Nakazawa, I. Iwasaki

Galvanic contact, occurring between electrically conducting minerals in flotation pulps, may affect the nature of mineral surfaces and influence their floatabilities. Rest potential and galvanic current measurements were made on an electrode combination of pyrite and pyrrhotite under nitrogen, air and oxygen aeration conditions. The results were correlated with their oxygen-consuming characteris- tics and flotation behaviors. The galvanic contact improved the floatability of pyrrhotite, but adversely affected that of pyrite. Auger electron spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy indicated that the formation of hydroxide or oxide and sulfate species of iron on pyrrhotite decreased, whereas that on pyrite increased when these minerals were held in contact. An electro- chemical mechanism was proposed for the observed behaviors.

Jan 1, 1986

By Kenneth W. Luke

A computer programing system has been devised to assist in open pit mine design planning. This system operates upon data generated for cross sections in the mine plan, and parallels present manual methods used in mine design, resulting in a minimal communications barrier between the mine planner and the computer. Input data for each cross section includes geologic interpretation and mine design parameters such as wall angles, bench heights, berm widths, and ramping system. The program will optimize the design of each cross section to give minimum stripping at any desired ore reserve level. This system is functional in the sense that it is easily adopted, changes in mine design parameters can be quickly evaluated, and each resultant design incorporates all recognized mining constraints.

Jan 1, 1973

By H. M. Strong, R. A. Oriani

THE technological interest attaching to light, age-hardening alloys for structural uses has been pointed out to one of us.1 A potentially interesting alloy would be titanium-rich Ti-Mg alloy, provided that sufficient solid solubility exists. or could be induced at high pressure. and provided also that age hardening can be induced by proper temperature and/or pressure annealing. It was decided therefore to explore the feasibility of producing a Ti-Mg alloy in the high-pressure apparatus. Experimental. Three high-pressure runs have been carried out. In each case the geometry of the sample was that of a cylinder of titanium of commercial purity, into which a narrow hole had been drilled along the axis; this hole was filled with magnesium wire,

Jan 1, 1967

By K. Osseo-Asare

The DIAGRAM computer program has been used to develop stability diagrams such as Eh-pH, log [CNI-pH, and log [Me]-pH for the systems Me-CN-H 0 where Me = Au, Ag, Fe, Zn, Cu, Ni, Co. More complex 2 diagrams involving sulfur- and arsenic-containing species are also presented. With the aid of these diagrams, a discussion is presented of the solution conditions (e.g. pH, [CN], [CNS], Eh) vhich influence gold and silver extraction in cyanide solutions. Special emphasis is given to the effects of ore minerals or calcination products, such as pyrrhotite, pyrite, arsenopyrite and hematite on gold-silver dissolution. Application of the stability diagrams to solution treatment operations such as cementation is also indicated.

Jan 1, 1984

By A. T. Yu

As the first year of full-scale shiploading operations nears completion, Chile's twin ports of Chafiaral and Caldera have proved instrumental in promoting the growth of that nation's iron ore industry. Located on the Iron Coast several hundred miles below Antofagasta, the two ports boast of new conveyor shiploading facilities uniquely adapted to their coastal environment. Until recently, iron ore producers in this region of Chile have been hampered by antiquated methods of loading crushed ore on ships for transportation to foreign buyers. Use of the "truck-to-lighter- to-ship" method, which dominated heretofore, was too slow and costly to permit expansion of productive mines and exploitation of new high-grade discoveries to meet the growing world demand for such ore.

Jan 8, 1960

By R. B. Sudderth

The recovery of copper by various combinations of processes centered around liquid ion exchange has certainly been accepted as a technically superior entity when compared to the widely applied classical method of cementation. While the technical aspect of liquid ion exchange processes has received much attention and acclaim through actual operating data, in particular the ease of handling solutions, percentage recovery, reduction of pollution, etc., the corresponding economic data has either gone unpublished or has been held confidential. Much of this economic data has now been made available for publication; and with this data, we at General Mills Chemicals, Inc., will attempt to present an accurate economic analysis of some liquid ion exchange plants and an economic comparison between these plants and the typical cementation facility.

Jan 1, 1974

By T. W. Peterson, J. W. White, E. E. Krist

In developing a minicomputer application for an industrial grinding circuit, the control program is usually coded and the compilation is debugged on a remote access computing system. Final debugging must wait for installation of the minicomputer. This work reports on an alternative. Here both compilation and execution bugs are eliminated before the hardware is installed by testing the control program against a dynamic simulation. Attention is directed toward development of a particular real-time control program for an industrial wet grinding circuit in a copper concentrator. Specific data were supplied by the Anamax Mining Co. for a grinding division consisting of a rod mill followed by two ball mills in parallel. This information was used to set up a plausible model structure.

Jan 1, 1977

By T. S. Mohibatsela, R. V. Ramani, C. V. Manula

The Mineral Engineering Department of The Pennsylvania State University has developed a suite of computer models for anthracite open pit mining (Fig. 1)1 Individual sub-systems have been developed to (a) interpolate geologic field data to obtain coal tonnages, waste volumes, and strip ratios; (b) simulate equipment performance on selected pit profiles to generate data required to choose coal and waste removal equipment; and (c) evaluate selected cost factors to determine either a rate of return for a specified selling price or vice-versa. This paper describes the application of two of these subsystems, namely, the Reserves Model (GEOL) and the Open Pit Materials Handling Simulator (OPMHS), and how these may be applied for the selection of equipment for a prime anthracite mining site.2

Jan 1, 1981