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By E. R. Johnson

THE copper concentrator of the Braden Copper Co. is at Sewell, Chile, on the western flank of the main Cordillera of the Andes, at an air distance of approximately 50 miles southeast of Santiago, the capital of Chile. The region is mountainous and space is at a premium because of the rough terrain and the danger of snowslides. The ore, a porphyry copper, is mined by a block-caving method in the El Teniente mine. It is hauled to the crushing plant, a distance of 2.6 miles, through a tunnel because of the severe climatic conditions. The usual large, coarsely set, primary reduction machines found in many ore-treating plants are not required because of the mining method employed and the limiting 12-in. spacing of the grizzlies at the head of each ore pass in the mine. It is the purpose of this paper to describe the numerous improvements made in the crushing section of this large flotation concentrator during the past 15 years to increase the efficiency of the plant and to raise the daily output from around 20,000 to 30,000 tons. The reader should keep in mind that all changes were made within the existing building because of the limited space and the high cost of the heavy mill construction required to withstand the snow loads. The present plant, as well as the former, operates on a 24-hr, 7 days a week basis. FORMER PLANT The crushing plant commenced operations at its present site in 1921, the main equipment being No. 7 1/2 gyratories, followed by 48-in. horizontal Symons disk crushers. Fines were removed by 1-in. stationary grizzlies ahead of each unit. In 1924 a third stage of crushing was provided by the addition of 55 1/2-in. rolls in open circuit. During 1925, the Symons disks were replaced by 73 1/2-in. rolls. All the rolls were changed to closed circuit, with elevators and screens to give a final product of 9 pct plus 3-mesh. The flowsheet of a typical crushing section of this period is shown in Fig I. The ore was withdrawn from a common bin serving the five crushing sections in the plant by means of any number up to six 36-in. wide-apron feeders, which discharged onto a common conveyor belt. This conveyor was equipped with a magnetic head pulley and the crusher attendant was stationed near the discharge end to pick out pieces of mine timber that might be in the ore. The ore was discharged over a 1 3/4-in. spaced bar grizzly and the oversize of this grizzly was crushed by a No. 7 1/2 McCully gyratory crusher set at 1 3/4-in. opening on the closed side. The grizzly undersize joined the gyratory discharge and was conveyed to a set of 73 1/2 by 20-in. Garfield rolls set at I in. These rolls operated in closed circuit with a bucket elevator and two vibrating screens placed in parallel.

Jan 1, 1947

By Edgar F. Cruft

It is sometimes said that "mines are made, and not found". I rather doubt that the exploration geologist would be overly sympathetic to that statement, and, of course, like most one-liners it is only partly true. As an explorationist who has been involved in building his own company over the last ten years, and by necessity has become a financier, I can appreciate what real grains of truth are in that statement, however. Because technical people are seldom taught financing in their basic training, and because they are usually not involved in it until at quite a senior level in their careers, the whole field often acquires a certain mystique. The engineering professions have too often believed financing is the province of the accountant or financial executive and just as we in the technical world are often too quick to bristle if the latter try to tread on our domain, the opposite can just as easily be true. Unfortunately, this is another example of a compartmentalized individual, and that is one thing the successful financier cannot be.

Jan 1, 1979

By A. J. de Witte

INTRODUCTION The importance of determining dips of subsurface formations in wells, especially in wildcat wells, is self-evident and need not be enlarged upon. Various dipmeter instruments have been described in technical literature1,2,3,4 over the years. The introduction of the continuous dip-meters3,4 has made the earlier types obsolete. Continuous dipmeter logs are run by at least two different major service companies. Included as part of the service are a limited number of dip calculations—usually 10—made at different levels from the log. Very frequently this is the total result of a dip survey. It is believed that dipmeter surveys would be of considerably more advantage if geologists and engineers were able to make their own calculations from the original records. Determination of dips from the dipmeter record starts with the correlation of three log curves taken at different sides of the borehole. It cannot be over-emphasized that the quality of the results hinges primarily on this correlation. Nobody should be better qualified to correlate logs than a subsurface geologist or field engineer. The next requirement is to have an easy yet accurate way of computing the dip from the correlated points. Service companies use a mechanical device for this purpose. Directions for a graphical method were given in a recent article by B. 0. Prescotts. This paper describes a different graphical technique which, in our experience, is simpler, faster and at least as accurate. The entire manipulation is carried out on the stereonet in a number of easy moves. The paper is divided into two parts. This first part contains the introductory sections and full explanation of the geometry involved. The second part reviews the reading of data from an actual field log and summarizes the practical rules for computation of dips, the whole process being illustrated by an example. Following the outlined procedure, one could calculate a good many levels in a relatively short time, thus being able in particular to check suspected anomalies such as fault zones or unconformities in as close detail as the log will permit. GENERAL EXPOSITION OF THE METHOD Prnciple of the Dipmeter The position of a plane in space is defined by the location of three points, not on a straight line. Referring to Fig. I, if a borehole traverses a bedding plane, we can determine the strike and dip of the bed by finding three points which are not in line along this plane. Such points as A, B, and C are obtained with the dipmeter. The device consists of three electrodes (or caliper arms)1, 2, and 3 spaced at 120 angles, as schematically indicated, whose readings are separately recorded (Curves 1, 11, 111, to the right). When electrode 1 passes the boundary of the bed, Curve I will kick, etc. From these curves, we know the relative distances of points A, B, C, measured along the axis of the hole. If A is at zero, then B and C are at levels d1 and d2 up the hole,

Jan 1, 1957

Economic conditions dictated the lead time from concept to commissioning of the Kambalda C.I.P. Plant. The high gold price prevailing at the time the Victory ore-body was discovered provided the impetus to establish a treatment plant with the utmost haste. Consequently only limited metallurgical testing was possible. Fortunately the Kambalda Metallurgical Department had experienced gold metallurgists among its' staff. This enabled a rapid assessment to be made of the ore types to be treated. Flexibility was the keynote in the plant design. Overseas practice and experience was drawn upon extensively, but it was known that problems uniquE to the Kambalda Plant would be encountered due to the high nickel content of the C.I.P. Plant feed and the difficult clays in some of the areas. These fears were well founded and problems have been experienced. However the plant design has enabled these problems to be absorbed, if not overcome, and design production rates were achieved and maintained within three month; of start-up.

Jan 1, 1982

By David C. Oyler, Paul W. Jeran, William P. Diamond

The Bureau of Mines is cooperating with the U.S. Department of Energy in a directional degasification project at the Emerald mine near Waynesburg, Pa. This project is designed to combine the highly successful underground horizontal degasification technology with surface drilling methods. The objective of this program is to demonstrate that directional drilling can be used as a technique for degasifying coalbeds ahead of mining to reduce the hazards of methane-air explosions in coal mines. The directional hole at the Emerald mine is designed to start vertically and enter the Pittsburgh coalbed horizontally. A 3-inch-pilot hole entered the Pittsburgh coalbecl at a vertical depth of 999 feet, The hole will be reamed to 8-3/4 inches in diameter, and 5-1/2-inch casing will be cemented in place. Three individual 3-inch-diameter, 3,000-foot horizontal gas collection holes will be drilled into the coalbed in a “bird foot” pattern. A corehole and vertical dewatering hole have been completed at the anticipated coalbed intercept. The dewatering hole was drilled to130 feet below the Pittsburgh coalbed, a depth of 900 feet, and 880 feet of 7-inch-OD casing was cemented in place. Seven vertical holes for monitoring the extent and progress of degasification have been drilled within the horizontal drilling area.

Jan 1, 1979

By B. J. Timmons

Depending upon which of two letters describing the theme of the session I chose to honor, the subject choices because either one or three. They were: "Applied Research and Exploration and Discovery" or "Applied Research in Exploration and Discovery." The final choice; to partially ignore both of them. That minor difference in meaning may be appropriate here, inasmuch as very minor research/exploration differences may also have profound impacts on discovery. To further set the stage, I consider myself an Industrial Minerals geologist, and more specifically primarily associated with basic construction materials crushed stone and sand & gravel. My remarks will apply primarily to those materials. Therefore, when the discussion instructions included emphasis on beneficial aspects (to name a few): "drill target definition; elimination of ore potential; ore forming environments; alteration studies, and isotope analysis," problems became apparent. Evidently, and although this was a form letter, the drafters of that letter had no idea what was involved in research for a construction materials source. My task may be great.

Jan 1, 1995

By AIME AIME

REGISTRATION and licensing of engineers is now being given consideration by a special committee of the Institute, authorized at the March meeting of the Board of Directors. The subject is one that has recently been or is now actively before engineering organizations in many of the States of the Union. In Washington, D. C., the Washington Society of Engineers and the local sections of ten national engineering societies, including the A.I.M.E., recently had a joint committee investigate the subject: this committee formulating a proposed law that has been presented to Washington engineers for their consideration. At the same time, the committee has summarized the reasons for and against registration of engineers in Washington, D. C. As many of these reasons are of more than local application, they are here reprinted so that all members of the A.I.M.E. may be informed on the subject. It is expected that some report of the Institute's Committee on Registration, State Councils and Professional Development will he made at some forthcoming meeting of the Board of Directors.

Jan 1, 1932

By Homer S. Anderson

To clarify what r mean about this long title, I would like to define the term technology. A standard definition of the word "technology" is "a technical method of achieving a practical purpose". Incidently, another definition of the term is merely "technical language". The same dictionary defines the word "technology" as "having a special, usually practical, knowledge of mechanical or scientific subject." Naturally, the practical purpose of the subject with which we are concerned is solving of problems we encounter in the mining industry. I might further describe the subject of this discourse by defining the term "manager". An old definition, "one who dispenses the duties of his position with care and economy." In line with the above definition most of the technology with which we in the mining industry are confronted with deals with some form of cost reduction. This may be related to the speed of doing an operation or to saving of labor or supply costs. These can be improvements of an existing method or the result of new processes or inventions, such as new machinery.

Jan 1, 1974

By C. C. Harris

The 3-parameter equation* was introduced1 as having the necessary form and flexibility for describing the major features of size distribution curves. Also, Eq. 1 was shown to contain most of the widely used 2-parameter equations as special cases. Special methods are necessary in order to determine the parameters of 3-parameter equations by graphical means. The procedure given previously required double graphical interpolation followed by regraphing the interpolated data. The theoretical basis of the method was a difference equation eliminating y. Several other methods for obtaining the parameters have been under development and one method appears to overcome the disadvantages of the earlier method and satisfies several procedural requirements. The points in favor of the new method as compared to the earlier method are as follows: 1. Estimation of the quality of fit is direct, and is in fact an essential part of the procedure. 2. The data is plotted directly without the necessity of interpolation from a graph. 3. The method makes use of Rosin-Rammler2 paper which because of expanded scaling in the coarse sizes leads to improved accuracy1 as compared with the log-log plot for the Gates3-Gaudin4-Schubann5 representation. 4. There is a gain over the earlier method in overall accuracy and in simplicity.

Jan 1, 1970

Some years ago it was my good fortune to inspect some coal properties in Germany, and the most striking impression I received on my trip was that in that country every one in the coal industry, miners and operators, was proud of the fact-not apologetic about it-and that industrially coal was looked upon as a King. The explanation, of course, was that at least 90 per cent of the entire mineral value produced in Germany was from coal, and that it was the very foundation of the nation's industrial life. The feeling was so different from that existing in the United States among those engaged in producing coal that it made a profound impression on me, and many times since then I have speculated about the reasons for the difference in opinion in the two countries. Here, of course, our units are much smaller and more numerous, there is not so large a proportion of technically trained men, and we have the American trait of depreciating the things we do at home; but among those not actively

Jan 1, 1935

By George M. Fowler, R. E. Illidge

Part I. Developing BY GEORGE M. FOWL INTRODUCTION The Tri-State district comprises an area of about 2000 square miles in southwestern Missouri, southeastern Kansas, and north [ ] eastern Oklahoma. The part that is in and contiguous to Missouri is still sometimes designated as the Joplin district (Fig. I). EARLY OPERATIONS Mining operations in what is now the Tri-State district date from about 1848 and have been continuous to the present. Apparently the first discoveries of ore were made about the same time near the present sites of Joplin, Oronogo, and Granby. Lead minerals were found at grass roots, probably in shattered rock in shallow excavations, then these minerals were followed in shear zones to deeper horizons. The mining of zinc followed. Before 1874, zinc ore was worthless and discarded as waste. According to published records, the total production of lead to that date was 49,000 tons of metal from 70,000 tons of concentrates. PRODUCTION The aggregate ore production from the Tri-State district was recorded at interval

Jan 1, 1943

By Brathwaite RL

The gold-scheelite-quartz lodes of the Wakamarina valley were the most productive of the mesothermal gold-bear in the Marlborough Schist. Most of the production came from the Empire City and Golden Bar mines which worked tug, Golden Bar lode. Only 134 m of its 1800 m strike length are accessible, in the No. 2 level of the Golden Bar Mine. A fau I has downthrown the Golden Bar Mine section by 2 47 m and displaced it left-laterally by 18 m. The lode is a typical ribbon-banded mesothermal vein, averaging c. 1.75 m wide, and enclosing narrow horses of schist country rock. It i composed of bands of milky "buck" quartz with thin laminae of schist. Scheelite occurs in short strings of grains withi quartz on the footwall side of the lode and also in small quartz-carbonate veinlets in the foot wall and hanging wall schist The lode quartz contains only localised traces of pyrite and arsenopyrite. They are more abundant in the wall-rock schist.

Jan 1, 1995

Some years ago it was my good fortune to inspect some coal properties in Germany, and the most striking impression I received on my trip was that in that country every one in the coal industry, miners and operators, was proud of the fact-not apologetic about it-and that industrially coal was looked upon as a King. The explanation, of course, was that at least 90 per cent of the entire mineral value produced in Germany was from coal, and that it was the very foundation of the nation's industrial life. The feeling was so different from that existing in the United States among those engaged in producing coal that it made a profound impression on me, and many times since then I have speculated about the reasons for the difference in opinion in the two countries. Here, of course, our units are much smaller and more numerous, there is not so large a proportion of technically trained men, and we have the American trait of depreciating the things we do at home; but among those not actively

Jan 1, 1939

By K. Harris, J. B. Wahl

Ni-base superalloy cast materials provide an outstanding balance of high temperature strength, fatigue resistance, oxidation resistance and coating performance and can be produced to very tight tolerances in extremely complex configurations, such as axial and centrifugal integral cast turbine wheels. As a result, cast superalloys are used in the most demanding applications of aero and industrial gas turbine engines. Use of these materials is expanding to smaller microturbine, turbojet, turbocharger and missile engine applications due to this unique combination of desirable properties. This paper will present an overview of the application of investment cast Ni-base superalloys and process capability to small turbine and missile engines.

Jan 1, 2010

By E. D. Peters

The Sudbury ore-deposits possess a peculiar interest for a variety of reasons. In the first place, they are deep within the borders of the Huronian rocks, and are consequently amongst the oldest deposits that we know of, unless, indeed, the ores were deposited at a much later period than the country rock. Again, they carry nickel in unusual proportions, and lastly, they are unique in containing a small amount of platinum, although arsenic is not present. I shall not pretend to go into the geology of this region. The Huronian and Laurentian rocks are familiar to all American geologists, and these present only the usual series of gneiss, graywacke, quartzites, greenstones, clay-slates, etc., characteristic of this gigantic system of rocks, which has excited so much discussion of late years. As in all parts of Canada where it occurs, I believe, the rocks of this system are tilted to such an extraordinary degree that it may be said that the whole country is standing on edge at an angle of something like 70°. The general strike of these rocks is southwest

Jan 1, 1890

By G. Voiloshnikov, A. Bogudlova

"The deleterious effect of carbonaceous matter during cyanidation of gold ores (so called preg-robbing) has been recognized for many years. Based on this, a new method using flotation to reduce the content of carbonaceous matter was developed. Low-sulfide gold-bearing ore with carbonaceous matter of 0.14% from a Russian deposit was processed. The purpose of these tests was to compare two flow sheet options. Option I comprised removal of carbonaceous product prior to sulfide flotation. Option II comprised removal of carbonaceous matter from flotation concentrate. It was found that the content of carbonaceous material can be reduced in sulfide gold-bearing concentrate prior to leaching. High gold recovery was observed during the separation of carbonaceous material prior to sulfide flotation using Option I. Due to lower reagent consumption the costs for reagents were decreased using Option II. The results have shown the effectiveness of a new method. Patent No. 2783808 was obtained for removal of carbonaceous material prior to sulfide flotation. This information will be used to design a large processing plant flow sheet in Russia."

Jan 1, 2014

Mining machine cabs were built to comfortably fit 90 percent of adult American males, and have controls that allow fast natural reactions during emergencies. These cabs and controls also fit 40 percent of the adult female population in the United States. The operators are also positioned for good visibility and for protection from roofing and ribbing hazards. Two basic designs were developed, one for seam heights on the order of 4 feet I and the second for seam heights near 8 feet. The sitting position of the largest person within the sample size group (termed a "95th percentile man") determined the basic cab shapes. The size of different parts of the human body and how they work together I established other design features of the cab. Areas of visibility, limits of operator movement, comfortable seating angles, etc., were carefully identified for the largest and the smallest persons within the sample size group. Placement of controls was based on these findings. The controls are designed and placed to allow operation with minimum physical strain and fatigue. See chart on other side of sheet.

Jan 1, 1978

By W. H. Ode, W. A. Selvig

In 1938 , the Bureau of Mines cooperated with Subcommittee XV on Plasticity and Swelling of Coal ( C. C. Russell , chairman ) , of Committee D-5 on Coal and Coke , A.S.T.M. , by testing various methods for determining expansion and plastic properties of a series of coals of widely different coking properties . One of the tests made by the Bureau was the British Standard Method for the Crucible Swelling Test for Coal.5/ Briefly , this swelling test consists in heating 1 gram of pulverized coal in a silica crucible over a gas flame under prescribed conditions to form a coke button which is compared in size and shape with a series of standard profiles numbered 1 to 9. These profiles are intended to cover the size and shape of buttons obtained from coals covering a wide range in plastic properties .. The number of the standard profile with which the maximum cross -sectional area of the button most nearly corresponds is recorded as the swelling index . Although the swelling test showed poor relationships with the various tests that were used for measuring expansion or contraction of coal during carbonization , it gave indications of having value in measuring free - swelling and caking properties of coals when burned on fuel beds . An opportunity to investigate this occurred when an engineer of an eastern public utility 'company reported pronounced differences in burning characteristics on grates of various shipments of Pocahontas coal . Some of these coals gave trouble by swelling 'excessively and clogging the grates . Samples were ob- · tained , and it was found that the troublesome coals gave decidedly higher free -swelling numbers than did the coals that performed satisfactorily . Also , it was found that the free - swelling index test gave better differentiation between coals than could be obtained from the coke buttons from the · ´`standard volatile -matter test or from agglutinating - value results . The results of the free - swelling tests were considered by the Subcommittee on Plasticity and Swelling , and a special group of the subcommittee , under the chairmanship of R. A. Sherman , was delegated to study the test method . Ostborg , Limbacher , and Sherman , ofthe Battelle Memorial Institute , ' investigated the various factors affecting the test and found that the swelling index was a good indication of the suitability of coal for performance on residential -type stokers from the standpoint of the coking characteristics of the coal . Data were presented also showing that the indexes wer helpful in the selection of coal for industrial underfeed stokers .

Oct 1, 1946

By Thomas E. McNider, Robert C. Howell, J. W. Stevenson

As of the end of October, 1990, there have been eight spontaneous combustion heatings reported to the Mine Safety and Health Administration (MSHA) at the No. 5 Mine. A reportable heating is defined as one with elevated surface temperatures of the strata greater than ll°C (20°F) above the ambient. The first heatings occurred in November, 1986. The last three heatings were located near the start line of "K" Longwall Panel in the southwest where mining had begun on May 21, 1990. All of the heated areas had been at the time of detection, or were sometime areas of high ventilation pressure differentials or high air velocities. All of the heated areas are in an expanded seam with associated, extensive floor heave which is characteristic of all of the expanded seam thus far exposed by development mining in the No. 5 Mine. Jim Walter Resources, Inc. submitted a plan to MSHA which would reduce the potential for spontaneous combustion at the No. 5 Mine by reducing high air velocities and high pressure differentials in the gob. These two parameters are the dynamics which feed oxygen to the pyrite, thus initiating the oxidation process which can lead to spontaneous combustion. No. 5 Nine operated under this plan for 29 shifts before mining on the longwall was stopped by MSHA and the Spontaneous Combustion Control Plan revoked. This paper briefly details the geology of the expanded seam and history of the heatings. It also gives a retrospective view of the operation under the Spontaneous Combustion Control Plan and reasons why it was revoked by MSHA. Currently, knowledge of the reaction process of the footwall coal seams at No. 5 Mine and other potential spontaneous combustion seams in the United States is limited. There are techniques used in the United States and other countries to minimize the potential for heatings in spontaneous combustion prone areas. The No. 5 Mine has attempted to utilize this current technology. However, in deep, gassy mines the problem is complex.

Jan 1, 1991

By C. A. Allen

When the writers were asked to prepare a paper on this subject for this meeting of the Institute there was some question in our minds as to what to say that would be of interest to the members. You all know that Utah has some wonderful seams of good coal, on which have been opened some of the most modern mines in the United States, and that her coal operators have been putting forth many efforts to reduce losses due to accidents as well as disease. While I believe that the physical condition of Utah's mines is as good as in any other state we are not unaware of the fact that a great deal can still be done and we are always willing to frankly discuss the accident situation in the state. Dr. Murray has assembled some interesting figures showing the monetary loss due to accidents and disease which I will will proceed to give you to show the necessity of continued efforts in welfare work regardless of humane considerations.

Jan 1, 1922