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By Arvid E. Anderson

The paper describes the unique operating features of the Lebanon Concentrator Plant wherein both magnetic concentration and froth flotation are used. Chalcopyrite is selectively floated by the use of dual collectors, Aerofloats and secondary butyl xanthate. Both potassium ethyl xanthate and sodium isopropyl xanthate (dual collectors) are dissolved and emulsified with pine oil for the flotation of the pyrite. Sketches describing the plant operations are presented and plant operating metallurgical results obtained are also given. The optimum production of minerals by the froth flotation process is normally achieved [ ] smooth operating conditions, The process, because of its many variables, becomes an art as well as a science. Therefore, any phase of the operation which will aid the operator in his control of the numerous variables will help produce a smoother operating plant, One of the most important variables which the operator deals with is the addition of reagents, These are usually costly items and should be used discretely with minimum amount of waste, The danger is that ,this emphasis may reduce the reagent amount to a point below that required, or, on the other hand an excessive amount is added, Both conditions usually yield poor results. The drea of the metallurgist is to provide the operator with the tools enabling him to produce a good mineralized froth at all times. Normally the operator has no control concerning the type of reagents which he must use. This has usually been worked out for him in the laboratory and by plant-scale tests. He does have limited authority to control the amounts of the reagents at his disposal. This, I believe, is as it should be. However, the operator should be provided with the best combination of reagents for his particular job. The providing of this combination of reagents for his particular job, The providing of this combination is often difficult, yet it is very important in order to yield good results, With this in mind, the dual collector idea was introduced for the selective flotation of chalcopyrite, and also later for the flotation of pyrite at the Concentrator Plant of the Bethlehem Cornwall Corporation in Lebanon, Pennsylvania, Supplying several types of collectors has given the operator an additional effective tool, even though great variations are encountered in ore tonnage treated and in ore composition, This paper deals with the use of the dual collectors and with the addition of the reagents in the form of a pine oil emulsion, or more accurately, a pine oil suspension. It is hoped that other operators may find the ideas helpful. There does not seem, to me, to be definite scientific fact which would substantiate the necessity for the use of dual collectors. However, in actual operations, the metallurgical results at Lebanon became more uniform with the use of dual collectors, I look upon it as an "insurance policy" which greatly aids the operator during those periods when he is having trouble, One theory has been advanced, i.e. one collector has a greater tendency to float the coarser minerals, whereas the other one may float the finer ones. Consequently, a combination of the two collectors will result in optimum recoveries, There has been some evidence that this is true, but it is not conclusive, on the other hand, the use of a xanthate-pine oil suspension (or emulsion) should speed up the surface reaction of the collector with the sulfide minerals, result¬ing in more uniform flotation, This has definitely happened in our particular case. A more interesting unexplainable observation has also occurred; i.e., the xanthate solution does not appear to lose its strength as rapidly when it is in the form of an emulsion (or suspension), This was first observed when a 50 gallon drum of a 20% ethyl xanthate solution was taken to Wilmington, Delaware, for a laboratory test, using a homogenizer to produce the xanthate-pine oil emulsion. Upon arrival, the drum of xanthate had developed a considerable internal pressure, The relief of this pressure was accompanied by a strong odor, When the emulsion was returned to Lebanon for the plant test orders were issued to release the pressure prior to emptying the emulsion. Nopressure had developed within the drum and there was no unusual odor present, Since this time it has been observed that xanthate pine oil suspensions have greatly decreased the possible decomposition of the xanthate solutions. In fact, suspensions have been exposed for more than a month without apparently effecting their reactions in the flotation plant. On the other hand, we found that the regularly mixed concentrated xanthate solutions, after standing for several days, did not give the same results as the freshly made ones. This effect was greatly reduced by the use of xanthate pine oil suspension (or emulsion)

Jan 1, 1958

By Yu. A. Polozov, V. A. Lagunov, O. Yu. Lushinkova, Yu. I. Svirskiy, Eh. Ya. Kipko, Roy A. Williams

The STG integrated method of grouting can be divided into the several phases as outlined in preceding chapters. For convenience in describing technical procedures, they can be grouped as: 1. Investigations in non-geotechnical, exploration bore¬holes. 2. Drilling the holes necessary for geotechnical investiga¬tions and for grouting. 3. Conducting appropriate hydrogeologic tests in those holes and consequent calculations. 4. The preparation of a clay mortar. 5. The preparation of a clay-cement grout with additives. 6. The injection of the grout. 7. Checking the quality of the grout curtain. Items 2, 4, 5 and 6 are discussed below. These activities contain the procedural aspects of grouting. 7.1 DRILLING GROUT HOLES Grout holes belong to a very select class of drillholes. The necessary drilling equipment must enable the operator to drill the holes in inclined, twisting directions. In addi¬tion, the equipment must permit drilling under structurally and hydrogeologically complex conditions. The equipment must permit the operator to conduct specific testing activi¬ties in the drillholes. These activities include hydrodynamic analyses, flowmetric analysis, and the installation and re¬moval of deflectors, packers, grouting plugs, casings, lin¬ers, pumping facilities and other work. As explained in Chapters 5 and 6, the grouting of sat¬urated rock is conducted both through holes drilled from the surface and through holes drilled from the face of a shaft, drift, or tunnel. The drilling of grout holes from the surface can be carried out by an aggregate of equipment that can be the same equipment used for drilling exploration boreholes. Depending on the projected depth of the holes, the STG ZIF- 1200MR and ZIF-650 drilling rigs (or modifications of them) are used. The SKB-4, SKB-5 and SKB-7 high-output drilling rigs (workover rigs) have been used in recent years. The STG BMP-24 drilling rigs are used for carrying out the descent-lifting operations for drilling holes from the sur¬face. In a number of cases, the UKB-500C, URB-3AM and URB-2A power-fed drilling equipment is used for drilling holes from the surface. It should be noted that the drilling of grout holes usually requires an electric drive assembly. Drilling with diesel drive assemblies would be used only to preclude the possi¬bility of losing electric power during drilling operations. Turbine drilling would be used only for appropriate techni¬cal-economic reasons. The selection of the grout hole design is determined by the hydrogeological and structural geological conditions at the site as interpreted in Chapters 2 and 3. The design of grout holes must be as simple as possible in order to min¬imize costs. Hole design guidelines can be adopted as a basis for this purpose, unless site-specific conditions require otherwise. The mouth of the drillhole must be outfitted with a guide-pipe having a length of at least 2 m and an outside diameter from 219 to 234 mm. The upper part of the hole must be attached by a jig consisting of borehole casing that has a diameter ranging from 108 to 146 mm. The length of the jig h is determined by the equation [ ] where k = 1.1 to 1.2 is the load factor; P,, is the injection pressure of the grout into the mouth of the drillhole; D is the external diameter of the jig pipe; m = 0.6 to 0.7 is the work condition factor; T[ ].1 MPa is the bonding value of the rock cemented to the jig. The grout hole is drilled from the jig shoe to the de¬signed depth using a rock-crushing bit with a diameter of 93 mm or more. However in complex hydrogeological condi¬tions when the shaft intersects unstable rock, other hole designs can be used. The diameter of grout holes must permit an aggregate of investigations to be conducted in them using down-hole borehole geophysical and flowmetric logging instruments. It is necessary to cement the casing strings reliably in the grout holes, thereby permitting the injection of the grout under high pressure through the pres¬sure tight mouth of the borehole. Technological details for drilling grout holes such as the rotational rate of the drill bit, the axial load on the rock¬crushing bit, and the drilling fluid flow rate are optimized for the specific rock-hydrogeological conditions largely by experience. The hole diameter and type of rock crushing bit are important variables in these details of drilling. It is advisable to drill holes using water as the drilling fluid. However in those cases where the hole walls are unstable or under very high ground water pressure, the use of a well¬ engineered drilling mud should not be precluded. Unfortu¬nately, drilling mud can influence test results. When steeply dipping fractures with inclination angles of more than 60 to 70° are encountered, it is necessary to drill guided, inclined grout holes. This procedure permits the maximum number of fractures in each hole to be stu-

Jan 1, 1993

By VIVEK KUMAR HIMANSHU, PK SINGH, AK MISHRA, MP ROY, RAVI SHANKAR

Underground blasting has many challenges. The primary aim of blast designers is to optimize drilling and blasting parameters to deal with the associated challenges. Optimizing these parameters is currently based on various rules of thumb, which have many site-specific limitations. Accordingly, computation of these parameters using empirical rock fragmentation predictors can be useful for blast designers. This paper presents the results of work on burden-spacing determination by back-calculation from the empirical Kuz-Ram model for underground stope ring blasting.

By B. F. Dickerson

STRATEGIC METALS! Recently, this money accented cry has been heard in such diverse locales as Mining company boardrooms, Banker's offices, Stockbroker's quarters, Swindler's dens and Congressional committee rooms. (In some cases, these locales are one and the same). Is the strategic metals rush for real? Should it be? Our paper attempts to give a very generalized view of the subject for a few metals, points to a few potential, but generally overlooked sources of these metals, and offers conclusions based on our studies.

Jan 1, 1981

By Y. C. Kim

Although the first published optimum pit limit design algorithm by Lerchs-Grossmann dates back to 1965, the majority of the open-pit mines in the U.S. has not as yet adopted such a rigorous optimization algorithm. Instead, the floating cone approach initially developed by Kennecott Copper in 1961 is still used today for various reasons. However, shortcomings with the floating cone algorithm, particularly for precious metal deposits with erratic mineral distributions, have provided a renewed interest in optimizing algorithms.

Jan 1, 1988

By Larry D. Wayland

Almost 100 sedimentation ponds were conceptually designed for a large surface mining study area in northeast Texas. An approximate procedure was developed to economically estimate construction quantities in order to predict surface water control costs. This procedure utilized site-specific empirical relationships developed from detailed analyses on a representative number of proposed sedimentation ponds. Use of these equations provided earthwork volumes, and spillway pipe lengths. The procedure developed for this study is presented along with the results of a verification analysis.

Jan 1, 1983

By W. Z. Choi

A combined size reduction- liberation model of grinding has been developed to predict the product size distribution for both free and locked particles. The model is an extension of the population balance model for size reduction. Locked (or composite) particles have been subdivided into discrete classes of different compositions to obtain more detailed information. The model has been tested on a sphalerite ore from Tennessee. Liberation data have been obtained using an areal scanning technique on microscope images of polished particle mounts.

Jan 1, 1985

By Robert H. Scott

Developments during the past few years have brought coal-based composite fuels to commercial readiness. During the next few years, composite fuels will become available from a number of suppliers. Potential users must evaluate the combustion properties of these fuels to determine equipment and operating changes required for their use. Most work to date has been done with boiler applications. However, many potential non-boiler applications exist in the metals and minerals industry. These applications require specific evaluations appropriate for the processes involved.

Jan 1, 1982

By Joseph Rosta

The gold and silver review did not arrive in time for publication in the May issue. Gold The gold market generally was listless in 1992, although investors returned to the metal in the fourth quarter. The gold price declined for the second year in a row, averaging $11.05/g ($343.76/ oz), 5.2% lower than the $11.65/g ($362.44/oz) seen in 1991. The average price has declined more than 23% since 1987, when gold averaged $14.36/g

Jan 1, 1993

By John W. Robertson, Edwin A. Zink, Gerald P. Zink, John E. Wolgamott

Equipment which will reliably produce high velocity water jets for use in rock excavation is now available. This report reviews some cases where water jets were used in excavating low to medium strength sandstone in Colorado and Utah. The primary discussion is of water jet assisted rotary drilling for blast and bolt holes in tunnels, shafts, and chambers. The subjects include drilling performance, effects on work environment, safety, and controlled blasting results. Information is also presented concerning trench excavation utilizing water jets.

Jan 1, 1983

By A. V. Glembotsky, N. A. Greshnova, V. P. Seregin, V. A. Glinkin

Based on a new alternative depressant of zinc sulphide - dimethyldithiocarbamate- modern technology has been developed for the treatment of complex polymetallic ores. In addition to its general function (depression of sphalerite and iron sulphides to some extent), this double-acting reagent is a promoter for galena and silver minerals. Laboratory and plant tests, as well as industrial experience have all shown consistently higher silver recovery to the lead concentrate as compared with sodium cyanide, resulting in less pollution and a safer environment

Jan 1, 1995

By M. Mohammed, S. J. Jung

The prime criteria in the design of underground openings with complicated geological structures is ground control. Stability of underground openings for deep mines is critical because incorrect orientation or geometry of the shaft, stopes and accessways often results in the failure of openings due to high stress conditions. Current design procedures for complicated orientation and geometry of mines are rapidly becoming inadequate. In this study, the finite element method (ANSYS) has been used with optimization criteria to design safer, more stable underground openings.

Jan 1, 1995

By S. P. Brown, J. E. Worthington

Increasingly, exploration geology seems to be growing into a practice overly separated from production geology, yet the eventual purpose of exploration is a producing mine. To help in the search for new deposits, exploration "lessons" will be drawn from the papers given at the Fall AIME Applied Geology Symposium. In addition, examples will be re-emphasized to show how early observation of matters now routine to mine work (for example, hydrology, rock mechanics, oxidation state) can help increase the effectiveness of exploration.

Jan 1, 1992

By Alfredo Dammert

The paper presents the results of a model built at the World Bank in order to analyze the aluminum industry. Bauxite demand for the year 2000 is estimated as a function of alumina refineries' requirements and of non-metal uses for bauxite. Bauxite supply by countries or regions depends on economic factors such as investment costs, operating and transportation costs, as well as on tariffs and levies. Various scenarios are considered as a result of varying the assumptions of the model.

Jan 1, 1984

By F. Wendling, J. A. M. Cano

To increase its product competitiveness in the foreign market, Samarco Mineracão S/A has developed, at its pilot plant, high-MgO pellets for performing direct reduction simulation tests. Additives, such as dolomitic lime and magnesite, were used for increasing the pellet MgO content. Comparative direct-reduction simulation tests were conducted in Samarco and foreign laboratories. The results show that direct-reduction pellets with satisfactory metallurgical properties can be produced and successfully processed at increased temperatures in direct reduction furnaces.

Jan 1, 1994

By Yongqin Zhang

A single bubble released into surfactant solution first accelerates, reaching a maximum velocity then decelerates to reach a terminal velocity. Modeling this "velocity profile" is fundamental to understanding the motion of bubbles in flotation systems. This contribution considers the terminal velocity. Modeling is by a combination of the Navier-Stokes equation for flow around the bubble and the Marangoni effect induced by surfactant on the bubble surface. Numerical simulation is shown to agree with experiment for bubbles in pure water and surfactant solutions.

Jan 1, 1999

By M. T. Ityokumbul

Flotation is a surfaced-based separation process that exploits the differences in the hydrophobicities of the components. In the present paper, a review of both established and emerging nonmineral applications of flotation (oil removal, paper de-inking and separation of plastics) is presented and discussed. For each application, the theory of the process is compared and contrasted with mineral flotation. It is shown that the mass-transfer approach to flotation offers a good starting point for the analysis of these separation processes.

Jan 1, 1999

By John W. Critchfield

This paper presents an overview of some of the basic issues related to tunnel construction in the presence of flammable and toxic strata gases. Gas properties and possible sources are outlined for the various gases that are commonly encountered underground. Assessment of potential gas hazards prior to construction is discussed. Measures for mitigating the problem during construction are summarized. This RETC Session on Gassy Ground has been organized by the Underground Technology Research Council (UTRC), Technical Committee on Gassy Tunnels.

Jan 1, 1985

By H. H. Murray

Tactical R & D is research and development for a specific application or applications. The mineral scientist has to define and understand the physical and chemical parameters required for a specific or potential application. Then the researcher must know the structure and composition of the mineral and its physical and chemical properties. Can these properties be changed by processing particle size and shape modification, and surface chemical treatment? Examples of tactical R & D in the industrial minerals area will be described.

Jan 1, 2003

By Rick Wright, Gregory L. Raines

San Diego’s need to access underground space has dictated a long history of tunnel construction. The subsequent need for water, coupled with San Diego’s natural attractiveness, has led to significant population increases and the need for the construction of even more tunnels. This paper will provide a historical summary of the progression of mines, tunnels and trenchless technology construction projects that contributed to the advance of current technology, feasibility, and constructability. A bibliography of relevant reports and data is included.

Jan 1, 2001