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By Félix Lewandowsky

El presente texto describe las actividades para corregir los pasivos ambientales heredados y asumidos bajo responsabilidad de la Compañía Minera Colquirrumi S.A. Para ello, se elaboró un plan de cierre de los cuatro depósitos de los relaves de Hualgayoc donde se busca mostrar los criterios utilizados, los estudios de ingeniería y la forma cómo se ejecutaron las obras de cierre definitivas de los depósitos de relaves.

Jan 1, 2015

By Jon Pocock, Ashma Singh

The traditional approach for the beneficiation of South African siliceous sedimentary phosphate ores has been reverse cationic flotation. The robustness of this approach, however, has been a concern due to its sensitivity to parameters such as slimes content, headgrade ( P2O5 and SiO2 content), reagent dosages and conditioning times. The phosphate mineralisation for the ore body under investigation is predominantly carbonate fluorapatite composed of mainly quartz and apatite and minor amounts of chlorite, ilmenite and carbonates. Beneficiation of low grade sedimentary ores containing calcareous impurities, such as calcite and/or dolomite in addition to siliceous gangue, is required to meet the increasing demand; therefore, much research has been carried out to find an alternative technique to beneficiate this material. This paper investigates traditional flotation approaches versus the currently adopted ‘Crago Process’. Comparative results are presented in terms of upgrade potential for the production of concentrate rock for downstream applications. The novelty of the ‘Crago Process’ lies in its double stage approach, i.e. direct fatty acid flotation followed by reverse cationic amine flotation. The Crago process was able to achieve higher upgrades reporting at 32.1% P2O5 compared to conventional cationic flotation only achieving grades of 18.5% P2O5. Furthermore, the recovery gain was 3%.

May 13, 2023

By A. Nieto

This article is a review of previous discussions about underground mining method selection and classification with the purpose to clearly define and classify the two groups of variables (indicators) involved in the mining selection process: key deposit indicators (KDIs) and key mining method indicators (KMIs). This paper provides a simple and clear approach for the classification and selection of a feasible underground mining method based on a predetermined set of favorable deposit characteristics, which are defined as key deposit indictors (KDIs). This article also gives a summary of the key advantages and disadvantages associated with every underground mining method based on their key mining indicators (KMIs). The selection method given in this paper is based on defining field KDIs and comparing them to the KDIs that are favorable to every considered mining method. By cross validating a matrix of favorable KDIs, the paper presents a simple approach to rank several underground mining methods using a scale from favorable to less favorable accordingly to the ore deposit characteristics (KDIs). KMIs are used to further complement KDI rankings by analyzing every method’s KMI performance based on the expected productivity of the mining operation being considered. To further assist the reader through the selection process, this paper gives basic sketches representing each of the primary underground mining methods discussed in this paper. Each method is given using the same 3D isometric view as spatial reference to assist the reader with visual interpretation and comparison between methods.

Jan 1, 2010

ALABAMA Aldrich.-Lloyd, T W Anniston.-Carrington, F G Gerber, A B Heimrod, A A. White, H E Ashland.-Barton, J C Sturdevant, J C Bessemer.-Abbott, C E Ball, T L Hines, H K Hodgkin, W -0. Salmon, H S Thompson, N E Birmingham.-Adams, J H Adler, J. E Aldrich, T H Aldrich, T H, Jr. Ball, E M

Jan 1, 1923

By James F. Devine

The radial, vertical, and transverse components of particle velocity were recorded by Bureau of Mines investigators along gage arrays extending in one or two directions for 145 to 3,170 feet at five quarries. Of the 39 quarry blasts, 12 were instantaneous blasts, 5 were of the one hole per delay type, using millisecond delayed caps, and 22 were multiple hole per delay type employing millisecond delay detonating fuse connectors. Charge weight per hole ranged from 8 to 1,500 pounds, and the charge weight per delay interval, including the instantaneous blasts, ranged from 25 to 4,620 pounds.

Jan 1, 1966

By J. Kalynchuk, R. Poulin, R. Pakalnis, D. Peterson

"A market survey of all underground mines in Canada (Fig. 1) was completed to determine the ex1ent to which cable bolts are being used as ground support. One hundred and nine questionnaires were distributed with 65% of them being returned completed. As a result, the quantity, types and locations of cable bolt installations have been determined. In addition, the grout pumps used, time required and cost of installations have been addressed. The popularity of other support types used in underground mines is summarized.IntroductionRock reinforcement consists of installing support within the rock mass (internal) or within the excavation (external). Within the past twenty-five years several new types of ground support have been introduced within the mining industry. Cable bolts were first introduced to the Canadian mining industry in the 19605 (Gramoli, 1975).Cable bolts have gained increased acceptance as a method of ground support during the past decade. The cable bolt is comprised of one central wire surrounded by six slightly smaller outside wires and typically having an over-all diameter of 15.2 nun to 15.9 nun (0.6 in. to 0.625 in.). The cable wires are made from high-strength steel with an ultimate strength of 26 tonnes (58 000 Ibs) (Goris, 1990). Current cable bolting practice consists of cement grouting one or more steel cables within a drill hole in order to reinforce the surrounding rock mass. Cable bolts are a form of internal support and are generally used in open stoping and cut-and-fill mining methods (Fig. 2).They can be either tensioned (active support) or untensioned (passive support) and may be of any length, though for underground mining applications, they are generally less than 20 m (65.5 ft) and are untensioned. A major advantage compared to previously used ground support is that the cables are flexible and can be coiled to approximately 1 m (3.3 ft) diameter coils allowing relatively long support to be installed in areas with limited head room (1.8 m).With the advent of bulk mining methods which require comparatively large stopes, it has necessitated the use of relatively long support tendons to stabilize the large spans being created. As a result, the use of cable bolts for ground support in mines has increased significantly within the past decade."

Jan 1, 1995

By A. Roy MacLean

"Cape Breton is an island on the eastern extremity of Nova Scotia, Canada. Here, coal mining under the Atlantic Ocean has been a way of life since the early French militia mined coal for heating purposes in 1720. Despite many ups and downs over the intervening years, the coal industry has survived and is now in a favourable position to benefit from the upswing in international coal usage.Mining in Cape Breton Early mining in Cape Breton was done by hand picks and shovels. The coal was loaded into mine cars which were hauled by horses to the main haulage system for transport to surface. Later, compressed-air cutting machines and drills led to the use of explosives to blast the coal so that it could be loaded by hand and transported as above. In 1923, longwall mining (by hand) was introduced. In 1950, the Dominion Coal Company developed the Dosco continuous miner in order to mechanize the longwall coal-getting operation. At this time, conveyor belts came into wide-spread use, along with diesel locomotives to haul mine cars from the longwall face to the main transport system. During this period, coal was also mined by conventional mechanized room-and-pillar equipment such as cutting machines, loaders, roof bolters, etc. This system evolved into the use of the continuous ·miners of today, which are employed in the Lingan Mine room-and-pillar section. However, this method is only satisfactory at shallow depths and gradients. For these reasons, almost all the coal in this coal field will be mined by longwall methods. In 1968, the Government of Canada expropriated the assets of the Dominion Coal Company on Cape Breton Island in order to prevent complete closure of an uneconomic industry by its owners. The government created, by an Act of Parliament, the Cape Breton Development Corporation which now operates the coal mines, coal preparation plants, railway, shipping pier and ancillary services (Fig. 2). Since its inception, the Corporation has closed three mines, opened two new mines, is in the process of developing a third new mine, and has invested heavily in the one mine which remains from its previous owners."

Jan 1, 1985

By E. J. Owen, S. Cherotich, V. T. McLemore

Breccia pipes are vertical pipe-like columns of rocks that provide conduits for fluid flow and open spaces for mineral precipitation, hence are focus areas for exploration. In the Gallinas Mountains, Lincoln County, New Mexico, there is recorded production of Cu, Pb, Ag, F, Fe, REE (as bastnäsite), and Au from 1902 to 1980, but no production reported from the breccia pipes. Previous studies described the occurrence of REE in breccia pipes, but their transportation and deposition controls are still unclear. The aim of this research is to characterize the magmatic-hydrothermal breccia pipes in order to understand the geochemical and physical conditions of deposition of REE and gold in the breccia pipes found in the Gallinas Mountains. There are more than 20 exposed breccia pipes that form a NE-trending belt about 3–5 kilometers, mostly gray-brown and consist of angular- to sub-rounded rock fragments, some host high concentrations of REE (80,500 ppm total REE) and Au (175 ppb). Preliminary studies suggest they are magmatic and intruded into the host rock and, subsequently, hydrothermal fluids precipitated F-REE and Au along the edges of some breccia pipes. More studies are underway to test this hypothesis.

Feb 1, 2023

By Charles M. Rolker

The Mariposa estate, a grant made by the Mexican Government to Juan 13. Alvarado, during the time when California was still under the dominion of Mexico, was purchased in 1847 by J. C. Fremont, and the United States patent issued to him in 1856. By sale, or its equivalent, money advanced, the property came into the hands of the Mariposa Company, June 25th, 1863, and through a varied existence of work and temporary inactivity, has as yet been kept as an undivided property, and rests at present with the Mariposa Land and Mining Company of California. I pass over this period of 15 years without giving the history of the ups and downs of the estate, partly because it is familiar to many, and also because I think in such a case this paper would assume too much the character of a narrative. The estate is situated in Mariposa County, California, about 170 miles southeast of San Francisco. It begins in lat. 37' 26' 38'' north, and long. 119' 55' west, and runs 6 miles north; thence 69 miles west; thence 5 miles northwesterly towards the Merced River; thence 84 miles southerly; thence 3 miles easterly; thence 1 mile southerly; thence 2 miles easterly; thence 2 miles southerly; thence 2 miles easterly; thence 1 mile southerly; thence 2 miles easterly; thence 1 mile northerly, and thence 2 miles easterly to the place of the beginning; embracing 44,387 acres (70 sq. miles) more or less. To describe this vast estate in detail as to its full geology, its numerous quartz veins, its many facilities to exploit them and work them by cheap methods, would lead me further than I intend to go at present, and I will content myself to describe the latest workings of the company and its immediate field of operations. As long ago as 1860 the late Dr. Adelberg advised the running of an adit from the northwestern edge of the estate at Benton Mills 011 the Mereed River. His object was to undercut the deepest workings of the then paying mines on the estate—the Pine Tree and Josephine. Following this advice, the tunnel known as "River Tunnel " was commenced. Its entrance is in S. 5, T. 4, s. R. 17 E. It is run in

Jan 1, 1879

By H. E. Gross

A plausrsle method of drilling beyond the continental shelves is set forth with limitations of the method. The continental shelves comprise the water-covered portions of land masses out to 600 ft. of water, or roo fathoms. The problems and possibilities of drilling beyond this depth are discussed in this paper. Introduction Much attention is being given the problem of developing petroleum beneath the open sea. Geophysical surveys have been made 26 miles offshore1 from the continental United States, and onco offshore ownership is established it is likely that there will be drilling for oil on the continental shelves. More than two years ago the author presented the means for drilling in deep water.2 at the fall meeting of the Petroleum Division of the AIME at Los Angeles. His concepts then were based on the use of rigid foundations suitable for drilling in water up to 600 ft. deep. The present paper suggests a method for drilling in deeper water. Possibilities and Problems of Drilling beyond the continental shelves It being conceded that because restricted deep-water portions of the hydrosphere might contain oil in commercial quantities, and that at any rate it is pertinent to know more of the nature of the lithosphere beneath the hydrosphere, the possibilities and problems of drilling beyond the continental shelves should be set forth. Drilling in open water would offer few if any advantages over drilling on land. These are: 1. The ocean transportation is available to deep-water drilling sites, and extensive pipe lines and roads are unnecessary. 2. Refinery facilities and markets perhaps are established on the near-by shore where adjacent fields on land are nearing depletion. 3. There is freedom from jungle pests and tropical diseases. 4. Competitive drilling is less likely. 5. Extensive areas attractive for development arc not yet under lease or concession. Disadvantages are great and numerous: 1. Storm hazards from wind and wave. 2. Expensive foundations, either rigid or floating. 3. Shutdown times because of weather. 4. Marine Regulations of Federal Bureaus in addition to customary regulations on land. 5. Frequent difficulty in moving men and materials to and from drilling platforms. 6. Extra precautions required in open sea. For drilling in water more than 500 or 600 ft. deep, rigid foundations2 become too costly, and floating foundations must be used, and they must meet the following requirements:

Jan 1, 1947

By H. E. Gross

A plausrsle method of drilling beyond the continental shelves is set forth with limitations of the method. The continental shelves comprise the water-covered portions of land masses out to 600 ft. of water, or roo fathoms. The problems and possibilities of drilling beyond this depth are discussed in this paper. Introduction Much attention is being given the problem of developing petroleum beneath the open sea. Geophysical surveys have been made 26 miles offshore1 from the continental United States, and onco offshore ownership is established it is likely that there will be drilling for oil on the continental shelves. More than two years ago the author presented the means for drilling in deep water.2 at the fall meeting of the Petroleum Division of the AIME at Los Angeles. His concepts then were based on the use of rigid foundations suitable for drilling in water up to 600 ft. deep. The present paper suggests a method for drilling in deeper water. Possibilities and Problems of Drilling beyond the continental shelves It being conceded that because restricted deep-water portions of the hydrosphere might contain oil in commercial quantities, and that at any rate it is pertinent to know more of the nature of the lithosphere beneath the hydrosphere, the possibilities and problems of drilling beyond the continental shelves should be set forth. Drilling in open water would offer few if any advantages over drilling on land. These are: 1. The ocean transportation is available to deep-water drilling sites, and extensive pipe lines and roads are unnecessary. 2. Refinery facilities and markets perhaps are established on the near-by shore where adjacent fields on land are nearing depletion. 3. There is freedom from jungle pests and tropical diseases. 4. Competitive drilling is less likely. 5. Extensive areas attractive for development arc not yet under lease or concession. Disadvantages are great and numerous: 1. Storm hazards from wind and wave. 2. Expensive foundations, either rigid or floating. 3. Shutdown times because of weather. 4. Marine Regulations of Federal Bureaus in addition to customary regulations on land. 5. Frequent difficulty in moving men and materials to and from drilling platforms. 6. Extra precautions required in open sea. For drilling in water more than 500 or 600 ft. deep, rigid foundations2 become too costly, and floating foundations must be used, and they must meet the following requirements:

Jan 1, 1947

By William D. Southard, Joseph W. Schlitt, Bruce P. Ream, Lawrence J. Haug

The operation of Kennecott 's Bingham Canyon copper precipitation plant, one of the world's largest, is described. This description includes a brief historical review of precipitation at Bingham and the general layout and operation of the present cone cementation facility. Current practices are based on results of studies undertaken to define improvements needed in each unit operation. These improvements were required to meet changing plant conditions and were implemented primarily within the constraints of the existing facilities. Specific unit operations included were the cone precipitators, the cone discharge thickener, the cone effluent settling basins, and the plate and frame filter presses. As a result of these improvements, loss of precipitated copper decreased and the degree of precipitation increased, raising copper recovery by 9 t/d. At the same time, iron consumption was reduced by 22.5 t/d. Problems in drying the cement copper were also overcome so that a product containing 12-15% moisture could be consistently delivered for smelting.

Jan 1, 1980

By C. M. Young

The safety lamp is the most common and convenient apparatus for detecting inflammable gases in mines, the presence of gas being shown by a blue flame, called the cap, if the wick has been lowered to suppress the luminous flame. The height of the cap increases with the proportion of gas and with the temperature of the lamp flame. Lamps of the Wolf type, the fuel of which is benzine, have a hotter flame than lamps in which vegetable oils are used, such as the Davy, and the Clanny, and are more sensitive than the latter and their many modifications. The Piehler alcohol lamp gives a still higher cap while the Clowes hydrogen lamp is most sensitive of all. While the effect of the temperature of the source of ignition is well known, the writer knows of no previous attempt to correlate the change of this temperature with change of the height of the cap produced, In order to determine the height of the cap at various temperatures, it was necessary to have a source of ignition the temperature of which could be accurately controlled over a considerable range. This condition was met by a coil of wire of high fusing point heated by an electric current controlled by a variable resistance. The use of a coil offered the further advantage of freedom from complications due to the flame of a burning fuel. Such a flame, being itself of variable height, would to some extent raise or lower the elevation of the base of the cap and therefore add to the difficulty of determining the height of the cap. Besides this, the presence of a small cap from the lamp fuel, commonly known as the "fuel cap," would interfere with the observation of small gas caps. After some experiment, a coil was made of platinum wire, No. 26, diameter 0.016 in. The coil was 17/64 in. (6.746 mm.) in outside diameter and had eight full turns in a length of 1/2 in. (12.69 mm.). This was connected to an electric circuit through an adjustable resistance, as shown in Fig. 1. In order to measure the temperature, a thermocouple was inserted in the center of the coil; the leads passed out at the ends and were ccnducted to a millivoltmeter. It is probable that the current of air passing upward through the coil resulted in the indication of a tempera-

Jan 1, 1920

By S Barrow, D Kent

Controlling the access of equipment, and people, has become more critical over the last few years for improving productivity and to meet safety responsibilities imposed by legislated obligations to have safety management systems. Hence Mine Site Technologies (MST) has spent the last three years completing the development of the tagging system to meet the mining industryÆs requirements, particularly streamlining access control. The basic tagging system tracks active Tags carried by personnel, or attached to vehicles and equipment, within underground zones. These Tags are detected (read) by Beacons placed strategically throughout the mine. As a Tag, or Tags, go past a Beacon they are read and the information transmitted back to the main database PC. This allows the current whereabouts of personnel and equipment to be known, as well as the history of their movements. The objectives of implementing the TRACKER Tagging System at Oaky No 1 Coal Mine were to: maintain a count of personnel inbye a particular point, and can alarm when a pre-set number is reached (eg the limit imposed by availability of SCSRÆs, etc); maintain a count of vehicles (and vehicle type) inbye a point, and can alarm if when a pre-set number is reached (eg when rated diesel units exceeds the limit for the ventilation present in that zone); manage the vehicle fleet, by keeping track of various vehicles underground better control and dispatch management of the equipment is achieved; keep track of equipment, knowing the location of equipment (such as forks, baskets, pumps, fans, etc) where last used or stored will minimise the risk of losing gear and assist in keeping inventory to a minimum; and locate personnel in emergency situations, by placing read Beacons throughout the mine the location of all personnel can be known in real time so that in the event of an emergency, their withdrawal can be monitored.

Jan 1, 2005

By F. Schott, M. James, G. May, E. Baker, C. Johnson, R. Bauer

Explosive demolition typically utilizes cutting charges to sever columns, detonating cord to time charges and provide an initiation path, and dynamite as a kicker charge. The kicker charges of dynamite are used to “move” columns out of alignment, causing collapse. Demolition projects involving dynamite can pose significant health and safety risks to workers and the public. Nitroglycerin in dynamite can cause dizziness, fainting, and other health problems. Moreover, dynamite placed directly on columns can result in fragmentation and cutoffs, preventing other charges from being initiated and resulting in incomplete demolition. Fragmentation can occur from columns and travel significant distances from the initiation point, sometimes reaching hundreds of meters away. This fragmentation can pose serious dangers to anyone in the vicinity, including workers and members of the public, as the debris can cause severe injuries and property damage. The force and velocity of the fragmented material can be unpredictable and difficult to control, making it important to take proper safety precautions and consider alternative demolition methods that minimize the risk of fragmentation. Previous work concluded that casing charges in water showed that a reduced dynamite charge mass could still successfully kick the charge out of alignment. This study aims to investigate the use of Pentolite boosters in water-cased charges as a safer alternative to dynamite-based demolition. The research involved testing various amounts of dynamite and pentolite boosters in water to compare their effectiveness in moving a hanging W-beam, which swung freely like a ballistic pendulum. Water-cased charges consistently move the column at a higher velocity than the traditional dynamite charge placed directly on the column. The method of water-casing increased the area of impact and impulse felt by the column, improving demolition efficiency when compared to traditional demolition methods as found in previous studies. Pentolite water-cased charges moved the column at 7.8 meters/second (m/s) while the dynamite water charge moved the column at 5.9 m/s. The increased strength and explosive properties of the pentolite contributed to this increase in velocity. This study showed that it is feasible to remove dynamite from demolition projects by utilizing pentolite boosters and that when considering safety, explosive properties, and effectiveness, pentolite boosters can be cost effective as well.

Jan 1, 2024

By J-P. Rossetti, A. Guerin, M. Jaboyedoff, L. Baillet, A. Mariscal, J. D'Amato, D. Hantz

"The processes leading to the fall of rock compartments from rock walls are poorly known as well as their velocity. It ensues that quantitative prediction of the failure time for a rock compartment which is presently stable, is not possible by a purely geomechanical approach. However a quantitative probabilistic prediction of rockfalls at the scale of a rock wall is possible if the spatial-temporal rockfall frequency can be determined or estimated (Hantz, 2011). For a better knowledge of failure processes and frequency, rockfalls have been detected in several rock walls, using annual terrestrial laser scanning, allowing comparison of the frequencies in different geological conditions. For one of these rock walls, the spatial detection have been completed by a precise dating of the events, using a quasi-continuous photographic survey (one photo every 10 mn), allowing the study of the influence of meteorological factors.The precise dating of rockfalls has been carried out for the Saint-Eynard cliff which towers above a residential area of the town of Grenoble (French Alps). The South-East facing cliff consists in bedded limestone gently dipping North-West and located at an elevation between 850 m and 1100 m. The surveyed zone is about 750 m large and 250 m high. Between 01/02/2013 and 26/11/2013, 65 rockfalls ranging between 0.01 m3 and 20 m3, have been detected by diachronic comparison of laser scanner data and dated by comparison of photographic images. The temperature at the elevation of the cliff has been calculated from the temperature measured (every 5 mn) at a meteorological station located at an elevation of 245 m and 2.5 km away from the cliff, using a temperature gradient of 0.003°C/m (D’Amato et al., 2014). The precipitation were measured 900 m away from the cliff at an elevation of 469 m. Different meteorological conditions have been defined: (a) “freeze” qualifies days with negative mean temperature (but with a thaw period, except for two days); (b) “thaw” qualifies days with positive mean temperature, but following a freeze day; (c) “rain” qualifies days with precipitation.Table 1 shows the rockfall temporal frequency for the different meteorological conditions. It appears that the frequency is about 6 times higher the freeze days, 2.5 higher the thaw days and 3 times higher the rain days than days without freeze, thaw or rain."

Jan 1, 2015

By L. O. Howard

What was perhaps the first attempt at basic converting in the Southwest was made by the late Charles F. Shelby at Cananea early in 1907, when he removed the acid lining from one of the 8 by 12-ft. barrel-type converters then in use at the reduction works of the Cananea Consolidated Copper Co. and substituted a lining of one course of magnesite brick. In this shell, he blew 21 taps (about 180 tons) of matte to white metal before the brick gave out along the tuyhre line. In every case, the white metal so made was transferred and blown to copper in other converters. The cost of the lining was $700 and Mr. Shelby gave up the experiment as impracticable. No further serious effort to bessemerize copper mattes in a vessel having a more or less permanent lining of basic brick was made by any of the large copper smelters in the Southwest until some months after Messrs. Peirce and Smith had brought the question permanently before the public, and had proved it to be a metallurgical and financial success by their work at Baltimore and Garfield. Early in 1911, the Cananea Consolidated Copper Co. had in operation at its reduction works at Cananea, Mex., several 8 by 12-ft. barrel-type converters lined with magnesite brick which had previously been operating with acid linings. In the 18 months following, these converters produced 50,000 tons of copper. In June, 1912, this company installed the first of its new equipment of six stands of electrically operated 12-ft. Great Palls type converters, and shortly afterward discontinued the use of the smaller shells. In September, 1911, the Consolidated Kansas City Smelting & Refining Co. had installed at its El Paso plant two 10 by 26-ft. Peirce-Smith converters. Later, in March, 1913, one standard Great Falls type converter was added. About the time the Peirce-Smith converters were going in at El Paso, the Calumet & Arizona Mining Co. was experimenting with basic linings in 7-ft. by 10-ft. 6-in. barrel converters at its plant in Douglas, Ariz. These efforts were sufficiently successful to enable the plant to "handle the total output of copper in these small shells until the standard Great Falls converters were substituted in June, .1914.

Jan 1, 1917

By Felix duBreuil

The present sampling procedure for evaluating the rock dusting conditions in a coal mine is time consuming. This study considers means by which this procedure could be simplified. Surveys were conducted in six coal mines in Pennsylvania to determine the in¬combustible content of the deposited dust. Some 2,000 samples were analyzed and statistically evaluated. It is suggested that the mean incombustible content could be obtained with fewer samples and smaller samples without greatly increasing the sampling error.

Jan 1, 1972

By W. Joseph Schlitt, William D. Southard, Bruce P. Ream, Lawrence J. Haug

The operation of Kennecott's Bingham Canyon copper precipitation plant, one of the world's largest, is described. This description includes a brief historical review of precipitation at Bingham and the general layout and operation of the present cone cementation facility. Current practices are based on results of studies undertaken to define improvements needed in each unit operation. These improvements were required to meet changing plant conditions and were implemented primarily within the constraints of the existing facilities. Specific unit operations included were the cone precipitators, the cone discharge thickener, the cone effluent settling basins, and the plate and frame filter presses. As a result of these improvements, loss of precipitated copper decreased and the degree of precipitation increased, raising copper recovery by 9 t/d. At the same time, iron consumption was reduced by 22.5 t/d. Problems in drying the cement copper were also overcome so that a product containing 12 - 15% moisture could be consistently delivered for smelting.

Jan 6, 1979

By J. P. Kerr, W. H. Cordell

Conditions in the oil and gas industry in Indiana were about the same in 1935 as in 1934. This is especially true of the old Trenton area and the Harrison County area where production was steady and almost no exploration and development took place. The past year has seen an increase in drilling activity and a decrease in oil and gas output in southwestern Indiana. In the state, 224 wells were completed in 1935, of which 48 were oil wells, 61 gas wells, and 115 dry holes. A few of these were old gas wells deepened to oil horizons. Twenty-six wells started during 1935 were not completed by Dec. 31. Approximately one-half the wells drilled were within proven areas. A relatively large number of wildcats, especially in Daviess, Pike and Gibson Counties, were in search of new gas supplies to supplant the diminishing resources in those counties. The decreased production of gas was due largely to the fact that existing supplies declined more rapidly than new fields could be brought on. The Alford field, in Pike County, which produced the bulk of the supply in 1934, was called on to do likewise in 1935, but was unable to respond sufficiently to keep up the yearly production for southwestern Indiana. During the last half of the year, the Oaktown field, Knox County, was connected with one of the principal pipe lines of the state, which helped to keep gas production above an unusual low. The decline in oil production was due almost entirely to proration during the first eight months of the year. The proration affected Daviess, Pike, Gibson, Sullivan and Vigo counties, which produce about three-fourths of the total for the state. After proration was lifted, the wells never quite reached the conditions existing before proration. The average daily production per well in Indiana is less than two barrels. The outstanding development in Indiana in 1935 was the drilling in the Oaktown field immediately before and after the laying of the 6-in. pipe line to the field. Almost without exception the wells came in with an open flow of two to four million cubic feet. At the end of the year, 26 wells were connected to the pipe line. Development of this field will

Jan 1, 1936