Search Documents

By W. P. Sykes

In an earlier paper1 the composition-temperature limits of the gamma iron phase in the iron-tungsten system were reported as approximated by thermal analyses. At that time no attempt was made to develop metallographic evidence of the coexistence of two phases in the iron-rich solid solution at temperatures between 900" C. and 1400" C.

Jan 1, 1931

By B. H. Cody

THE Morenci concentrator of the Phelps Dodge Corporation is a part of the project that was completed after five years had been spent in development of the open-pit mine, equipment and process testing in the former No. 6 concentrator, and construction of the reduction works. The reduction works, of which the concentrator is a part, is about a mile and a quarter southeast of Morenci, on the highway that leads up Morenci Canyon. The concentrator has a nominal capacity for the treatment of 45,000 tons of ore daily. The original plant, which has a rated capacity of 25,000 tons of ore daily and is now in its fifth year of operation, began production on Jan. 30, 1942. The addition, to increase the capacity 8o pct, began operation on Dec. 1, 1943. The equipment of the original plant has been described in MINING AND METALLURGY (May 1942). No changes in equipment were recommended for installation in the concentrator extension and only one major change, forced by a shortage of maintenance labor, has since been made. Metallurgical treatment has been altered in some ways as experiments progressed and as labor and economic conditions dictated. No complete description of the operation of the concentrator has been published, so this paper will record such operating and equipment changes as have been necessary, the operating methods that have been developed and the metallurgical results that have been obtained. Descriptions are given in the order of the processes with a flowsheet and an equipment list of each process for convenient reference. The questions asked by engineer visitors have guided the detail in which operation and maintenance are described. During the period Jan. 30, 1942 to Sept. 1, 1946, ore milled has totaled 43,595,253 dry tons, from which 1,643,885 tons of concentrate have been made, containing an indicated production of 783,164,809 lb of copper. The principal results obtained in operation of the concentrator during the years 1942 to 1945, inclusive, and to Sept. 1, 1946 are shown in Table 1. A graphic general flowsheet of the plant is given in Fig I. ORE The Morenci ore that is now being treated is a medium-hard monzonite porphyry in which the principal sulphide minerals are chalcocite and pyrite. A minor amount of covellite is present. Chalcopyrite and bornite have been observed under the microscope. The chalcocite occurs mainly as a coating on pyrite. Some of the coatings are so thick that the pyrite presents the appearance of being an inclusion in chalcocite. Some are less than one micron thick and are barely visible at 500 diameters magnification of a polished cross section. Some chalcocite is present as a dissemination in the gangue. Various oxidized copper minerals are present as a result of oxidation in place but they represent a minor proportion of the copper minerals of the ore body. Oxidation

Jan 1, 1947

By B. H. Cody

The Morenci concentrator of the Phelps Dodge Corporation is a part of the project that was completed after five years had been spent in development of the open-pit mine, equipment and process testing in the former No. 6 concentrator, and construction of the reduction works. The reduction works, of which the concentrator is a part, is about a mile and a quarter southeast of Morenci, on the highway that leads up Morenci Canyon. The concentrator has a nominal capacity for the treatment of 45,000 tons of ore daily. The original plant, which has a rated capacity of 25,000 tons of ore daily and is now in its fifth year of operation, began production on Jan. 30, 1942. The addition, to increase the capacity 80 pct, began operation on Dec. I, 1943. The equipment of the original plant has been described in Mining and Metallurgy (May 1942). NO changes in equipment were recommended for installation in the concentrator extension and only one major change, forced by a shortage of maintenance labor, has since been made. Metallurgical treatment has been altered in some ways as experiments progressed and as labor and economic conditions dictated. No complete description of the operation of the concentrator has been published, so this paper will record such operating and equipment changes as have been necessary, the operating methods that have been developed and the metallurgical results that have been obtained. Descriptions are given in the order of the processes with a flowsheet and an equipment list of each process for convenient reference. The questions asked by engineer visitors have guided the detail in which operation and maintenance are described. During the period Jan. 30, 1942 to Sept. I, 1946, ore milled has totaled 43,595,253 dry tons, from which 1,643,885 tons of concentrate have been made, containing an indicated production of 783,164,-809 lb of copper. The principal results obtained in operation of the concentrator during the years 1942 to 1945, inclusive, and to Sept. I, 1946 are shown in Table I. A graphic general flowsheet of the plant is given in Fig I. Ore The Morenci ore that is now being treated is a medium-hard monzonite porphyry in which the principal sulphide minerals are chalcocite and pyrite. A minor amount of covellite is present. Chalcopyrite and bornite have been observed under the microscope. The chalcocite occurs mainly as a coating on pyrite. Some of the coatings are so thick that the pyrite presents the appearance of being an inclusion in chalcocite. Some are less than one micron thick and are barely visible at 500 diameters magnification of a polished cross section. Some chalcocite is present as a in in the gangue. Various oxidized copper minerals are present as a result of oxidation in place but they represent a minor proportion of the copper minerals of the ore body. Oxidation

Jan 1, 1949

By Clement K. Chase

The ammonia leach for copper recovery is discussed from historical and current practice standpoints. The chemistry of the system is presented together with Eh-pH and copper-ammonia solubility curves. A list of metals forming ammine complexes is presented. The advantages and disadvantages of the ammonia leach as applied to copper recovery in conjuction with modern liquid ion exchange techniques are compared.

Jan 1, 1980

Recently the Colorado Engineering Council was formed "to coördinate the work of various technical, scientific, and engineering organizations, promote the welfare and professional standing of their members, and foster a more general recognition of the engineer in civic matters." The membership consists of local associations of members of the national engineering societies and other local engineering, scientific, or technical associations.

Jan 8, 1919

Members whose deaths were reported from Mar. 5, 1919, to Apr. 5. 1920 [Elected Died 1895 ANDERSON, ROBERT HAY 1920 1916 ATWATER, M. W 1919 1905 BARD, D. C. 1920 1893 BECKER, GEORGE F 1919 1914 BIGELOW, BRAXTON 1917 1917 BLACK, HERBERT F 1919 1911 BOWLER, ROBERT P 1919 1902 BROWN, ARTHUR H 1919 1913 BURNHAM, WILLIAM 1918 1905 Carnegie. Andrew 1919] [ ]

Jan 1, 1925

By H. M. Morse

During the year 1942 there were 66 wildcats drilling in Mississippi. One cored in oil sand, the Macro Drilling Company's Longbell No. I in Clarke County, but as yet it has not succeeded in recovering the oil. These drillings broughi to light five salt domes, two of which had heavy oil showing; one drilled by the Magnolia Petroleum Co. in Warren County, and

Jan 1, 1943

The Second Annual Safety First Dinner to the Liberty Bell Mine Crew was held on Apr. 7, 1916, in recognition of the second year without fatal accident and with few serious accidents. The address of the evening was given by the Rev. Edward Burns Martin, on "Safety and Citizenship," and was followed by informal talks on safety, health and citizenship.

Jan 6, 1916

By H. M. Morse

During the year 1942 there were 66 wildcats drilling in Mississippi. One cored in oil sand, the Macro Drilling Company's Longbell No. I in Clarke County, but as yet it has not succeeded in recovering the oil. These drillings broughi to light five salt domes, two of which had heavy oil showing; one drilled by the Magnolia Petroleum Co. in Warren County, and

Jan 1, 1943

By Robert M. Cox

A roof bolting theory and structural model are presented which explain the success of most roof bolting installations as the creation of a competent roof bolt reinforced rock arch within the immediate roof rock overlying an underground opening. Likewise, the failure of some bolted mine roofs can be explained as a failure to create a structually competent rock arch by roof bolting.

Jan 1, 1975

By George Krauss, Morris Cohen

NUMEROUS investigators1-4 have shown that one of the most conspicuous effects of the reverse marten-sitic transformation in Fe-Ni alloys is the stabilization of the austenite which forms on reversal. However, the present authors5 found a virtual absence of stabilization in a recent study of this subject. The purpose of this note is to account for the discrepancy.

Jan 1, 1963

By R. J. Lytle

Geophysical exploration for engineering purposes is conducted to decrease the risk in encountering site uncertainties. Such studies are needed in construction of underground facilities. Current responsibilities, opportunities and challenges for those with geophysical expertise are defined. These include: replacing the squiggly line format, developing verification sites for method evaluations, applying knowledge engineering and assuming responsibility for crucial national problems involving rock mechanics expertise.

Jan 1, 1982

By B. C. Woodfine

WHEREAS it is generally assumed that the highest temperature at which temper brittle-ness takes place is about 625°C, 1,2,3 Jaffe, Buffum, and coworkers have referred in several recent papers45,6,7 to the occurrence of temper brittleness in an SAE 3140 steel at 650" and 675°C. Their re- sults show that a considerable increase in transition

Jan 1, 1955

By Herbert H. Mellus

TODAY the tractor-drawn carryall scraper has a very important role in the Open Pit div. of Inspiration Consolidated Copper Co. Carryalls have already moved over 3 million tons of material at costs comparable to or lower than for conventional truck and shovel operation, and a major program of scraper stripping and ore production schedules has developed from early isolated scraper applications.

Jan 10, 1953

By James E. Breland

A case study of tangible and intangible costs incurred by a coal mining company for meeting the requirements of the Federal Coal Mine Health and Safety Act of 1969 is discussed. For clarity, the data is presented on a "before and after" basis, with special emphasis on safety records, costs, and production performance. The cost figures have been subjected to outside verification.

Jan 1, 1975

By T. Egleston

There has alrvays been atheory among those working placer mines that gold is both folind rusty," and becomes so under treatment, hy which they nleun, not that gold becomes coated with oxide: of gold, but that it, is either coated superficially or alloyed with some substsnee which prevents the contact with mercury,and thus precludenthe possibility of amtrlgamation. To such aoiiditions of the

Jan 1, 1881

By William L. Horner, James A. Lewis, Marion Stekoll

THE data in this paper show a relationship between measured productivity index and certain commonly measured reservoir characteristics. Comparison is made of theoretical radial flow assuming certain drainage radii and the tentative relationship shown by these data. Among the more important measurements found to correlate with productivity index are permeability, formation thickness, oil viscosity at reservoir conditions, and formation-volume factor.

Jan 1, 1942

By L. C. Binon

Exploration budgets are commonly determined by rules of thumb, such as a percentage of earnings or other fiscal measure. An appropriate exploration budget is the amount needed to achieve company goals. It can be determined by discounting the income expected from achieved goals. Budgets for individual projects are determined in a similar manner except that risk of failure is included in the computation.

Jan 1, 1984

By William I. Rau

This presentation will examine the role commercial banks will be expected to assume in financing international minerals projects, including a discussion of various financing techniques such as project loans, production loans, and production payments. A discussion of the necessity for completion guarantees, finalized sales contracts, reserve evaluations, management contracts, and marketing undertakings in conjunction with financing availability are also included.

Jan 1, 1981

By W. B. Mather

Literature dealing with rock drilling presents a mass of conflicting data. The principal cause of the confusion is attributed to varying definitions of the hardness factor of rock and cutting media. The future development of more efficient drilling methods demands that this problem be solved. The first step in the solution is the compilation of complete data on the physical properties of rocks.

Jan 2, 1951