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By M. Narasimha

The flow in a hydrocyclone classifier is highly turbulent complex nature of multi-phase structure, which has led designers to rely on empirical mathematical models for predicting the performance. A number of classifying cyclone models have been developed and successfully used in mineral comminution circuit simulators over the past four decades (Plitt, 1976 and Nageswararao, 1978). However, most of the mathematical models currently available to describe hydrocyclone classifier performance are based on single average mineral density component behavior. In industrial comminution circuits, the feed to the cyclone composed of a mixture of particles of varying degrees of liberation and sizes. The behavior of multi-component particles in a hydrocyclone is poorly understood and unaccounted for in most of the mathematical model equations available in the literature. There is evidence from a number of experimental data sets indicating the significant influence of the multi-component particles on measured cyclone performance. A concept for modeling the performance of hydrocyclones based on multi-component behavior is proposed in this paper. A set of semi-empirical model equations for cut-size, sharpness of separation are presented and the corresponding model parameters evaluated from the measured data are given.

Sep 1, 2012

By Wallace W. Key

The California pesticide industry in 1962 consumed about 30,000 tons of clay, talc, limestone, diatomite, sulfur, and other minerals as fillers (carriers and diluents) in pesticide formulation. This was 10 percent of the U.S. filler requirement for pesticides. About two- thirds of the California total was supplied by a few local mineral producers; the remainder came mainly from Florida, Georgia, and Wyoming. The objectives of this report are to provide data on quantities, sources, specifications, and market conditions for minerals used as fillers by California pesticide formulators. The study disclosed that specifications for mineral fillers have become more rigid and formulators have become more numerous in recent years. During 1962 over 1,200 firms registered 16,000 pesticide products with the Bureau of Chemistry in California. Factors which will tend to diminish future need for mineral fillers include the trend toward greater use of organic sprays rather than dusts and further development of biological controls, such as the development of sterile insect strains.

Jan 1, 1965

By Ruddle R. W.

The slags produced in copper smelting are largely composed of silica and ferrous oxide and may therefore be regarded as essentially ferrous silicates. A fair amount of information is available on the constitutions of the liquid slags used in copper smelting and, in this connection, the large volume of work being carried out on steelmaking slags should be helpful. Constitutional diagrams are available for most of the principal systems involved (SiO2-FeO; SiO2-FeO-Al2O 3; SiO2-FeO-CaO; SiO2-FeO- MgO; and SiO2-FeO-CaO-Al2O3) and these show that additions of Al2O3 and CaO reduce the freezing points of SiO2-FeO slags but that additions of MgO increase the freezing point. A certain amount of information is available on the thermodynamics of slags, but much further work on this subject is required. Modern theories of the constitution of liquid slags deny the existence of molecular compounds but consider that liquid slags are mixtures of various ions such as, Fe2+. O2- and SiO4(4-). Little appears to be known of the reactions between matte and minor constituents dissolved in the slag

Jan 1, 1953

By G. M. Kintz

The data in this circular were taken from publications of the United States Bureau of Mines and published annual reports of the Wyoming State Inspector of Coal Mines. The tables included are complete only' with regard to major disasters; the Bureau of Mines considers a major disaster one in which 5 or more men are killed. However, minor disasters and gas ignitions recorded in these publications are included. It is known that a number of gas ignitions have occurred of which no record is available. This is one of a series of papers by the Bureau of Mines giving by States available data regarding coal-mine explosions. This information is published in condensed form in the belief that it may be of vale to mine operators in preventing future coal-mine explosions.

Jan 1, 1934

By John A. Breslin

This report summarizes the principal activities and significant results of the Bureau of Mines respirable dust research program since passage of the Federal Coal Mine Health and Safety Act of 1969 and the Federal Mine Safety and Health Amendments Act of 1977. This program has investigated new and improved techniques and equipment to reduce or prevent the formation of dust during the cutting cycle; to dilute, suppress, or collect airborne dust generated during mining, handling, and processing; and to improve the measurement of dust levels for evaluation of engineering controls and for enforcement of Federal dust standards. The report is intended for mining industry dust control specialists and other interested parties. It includes a brief summary of the program to date, a section on future research plans and goals, and a list of publications resulting from the Bureau's respirable dust program.

Jan 1, 1982

By A. Trusiak

"Increasing energy costs in mineral processing is making it necessary for tighter controls over various parts of the concentrating process. Continuous monitoring and control of critical process streams can be easily performed by today's many computer systems. Indeed, the list of successful applications of computers to grinding and flotation control continues to grow. The day is rapidly approaching when the use of computers within concentrators for either process control or simply metallurgical accounting will no longer be a luxury, but a necessity. The benefits from such applications far out weight the initial investment.This paper describes the current application of a process control system at Brunswick Mining in north-eastern New Brunswick. Emphasis is placed on the control of a CuPb flotation circuit, and the benefits derived-from this control.No. 12 Cu-Pb Flotation: The complex nature of the Brunswick flotation process has been described else-where. 1,2,3 Four final concentrates are eventually produced, these being a Zn concentrate assaying 53% Zn, a 30% Pb concentrate, a 20% Cu concentrate, and a bulk Pb Zn concentrate assaying 35% Zn and 17% Pb. The Cu concentate, Pb concentrate, and bulk Pb Zn concentrate are all derived from a primary CuPb concentrate assaying 26% Pb, 11% Zn and 1.8% Cu.The No. 12 CuPb circuit produces approximately two thirds of the total primary CuPb concentrate. No. 12 ore, assaying 3.5% Pb, 9% Zn, 0.25% Cu and 100 g/tne silver, is ground in two parallel grinding circuits. Each line uses a 3.2 x 4.2 meter rod mill in closed circuit with two parallel 3.2 x 3.9 meter ball mills. Ball mill and rod mill discharges are classified in two stages of cycloning. The secondary cyclone overflow, or flotation feed, is controlled at 65% passing 37 microns."

Jan 1, 1981

"INTRODUCTION These safety standards for anthracite mines have been prepared for use as a guide for Federal inspectors. They are a revision of ""Tentative Inspection Standards for Anthracite Mines,"" published as Bureau of Mines Information Circular 7282 issued in May 1944 and used as a guide in Federal inspections. No provision made in these safety standards should be construed or operate to nullify any existing State statutes; they are intended to supplement the State statutes in the interest of increased mine safety. Mines are inspected in accordance with the Federal Coal-Mine Inspection and Investigation Act of 1941, Public Law 49, 77th Congress, H. R. 2082. Any unusual hazard noted by an inspector and not covered by these standards will be discussed in the inspection report, and suitable remedial procedure will be recommended.ARTICLE I. - SURFACE STRUCTURESSection 1. Breaker and cleaning plant.Electric switches and controls in breakers and cleaning plants should be enclosed.Where coal is dumped at or near air-intake openings, reasonable provisions should be made to prevent the dust from entering the mine.Section 2. Lamp houseNaphtha or other flammable liquids in lamp houses should be kept in approved containers or other suitable dispensers.Flame safety lamps should be permissible and maintained in permissible condition.Flame safety lamps should be properly cleaned, examined, and assembled by a qualified lamp attendant or other competent person before each period of use. Lamp assembly should again be checked by the person using it immediately before he enters the mine.When not in service, methane indicators, flame safety lamps, and electric cap lamps should be in the custody of competent persons responsible for maintenance and testing."

Feb 1, 1948

By L. H. Michaud

An existing mining company plans to extend their surface coal mining operations in central Pennsylvania. Although the proposed site contains pyritic material, the results of the acid-base accounting for the site show an overall NP:MPA ratio of 4.26:1 for the entire site. The pyritic material is, however, associated with the lower of the three seams to? be mined. If traditional dragline mining methods were used, this would result in the acidic material being placed at the top of the spoil piles, exposing it to air and water, and therefore to the formation of Acid Mine Drainage (AMD). Further concerns are associated with the fact that the alkaline material is not distributed evenly over the mine site. In order to prevent the formation of AMD, the company has proposed to mine the area using Truck/Shovel mining methods. This technique offers a more flexible alternative for cut sequencing and for the selective placement of waste material. Working with the Department of Mineral Engineering at The Pennsylvania State University, a mine plan was developed for this site. This plan results in the layering of the alkaline and acidic spoil in order to achieve an overall net alkalinity in all spoil areas. Mining of this site should therefore not result in the formation of AMD.

Jan 1, 1994

By Pete G. Kovalchik, Lynn A. Alcorn, Rudy J. Matetic, Adam K. Smith

Over-exposure to noise remains a widespread, serious health hazard in the U.S. mining industries despite 25 years of regulation. Most other categories of illnesses and injuries associated with mining have improved, with the exception of hearing loss. Mine Safety and Health Administration (MSHA) coal noise sample data collected from 2000 to 2002 show that 65% of the equipment whose operators exceeded 100% noise dosage is comprised of seven different types of machines. The continuous mining machine is first among all the equipment with 35% of the noise overexposures. The ational Institute for Occupational Safety and Health (NIOSH) is conducting research to reduce excessive exposure for operators of continuous mining machines and preventing additional cases of oise Induced Hearing Loss (NIHL) by developing low-cost retrofit noise controls for mining equipment. This paper describes a noise control for reducing the noise overexposures of continuous mining machine operators. Underground results show a 26.4% and 27.4% noise exposure reduction for the continuous mining machine operator. This research is providing the mining community with an additional noise control to be utilized on continuous mining machines, therefore reducing operator noise overexposure. Utilizing this newly developed noise control, along with previously proven controls for the continuous mining machine chain conveyor, will provide operators of these machines an opportunity to be within the MS HA-Permissible Exposure Limit (MSHA-PEL).

By Zetti Gavelán

Globalization and the search for new ore deposits inevitably lead to investment in foreign markets. Investors need to be aware of the effect of their venture on regional, social and economic issues when they invest. Decades of detailed statistics from various sources can be integrated and analyzed to predict the social-economic impact of investment, thereby mitigating risk. To this end, the correlation among variables such as foreign direct investment into mining (FDIM), reserves, and socio-economic indexes is examined. The investigation focuses on South America from 1992 to 2000. Throughout the past decade, South America has benefited from capital investment from more developed countries. This huge investment by the mining industry has impacted the South American economies and can be measured directly using the FDIM. Other economic variables investigated include mining gross domestic product, direct employment, and human development indexes. The correlation is based on data compiled from the World Bank, international risk assessment agencies, the United States Geological Survey (USGS), and the information agencies of various South American countries. Initial analysis of the economic data suggests various expected outcomes. For example, foreign investors may disregard a measured, highly negative country risk in deference to the quality of its mineral resources. It is important to note that the standard measures of country risk published by investment analysts are not industry or investor-specific. In the case of the investor, the level of accepted risk is based on their managed investment portfolio. It is noted that arguments for level-playing fields may be the antithesis of globalization. The discovery and exploitation of ore bodies in a globalized environment necessitates the development of economic measures that standardize mining-specific risk variables and trends. The latest published information on the security of mineral investments in South America is investigated by integrating databases of economic, geologic, production, human indexes, and risk ranking.

May 1, 2003

By Amila Sandaruwan Ratnayake, T. Dilmi. U. Wijewardhana, H. C. S. Subasinghe

The value addition potential of ilmenite was examined using several characterization techniques. Raw ilmenite is composed of 93.65 wt.% of FeOTiO2, 3.55 wt.% of SiO2, 1.22 wt.% of Al2O3, and the remainder being other minor oxides. Ilmenite and powdered carbonized coconut shells were mixed in the weight ratio of 4:1. A separate fraction of the same mixture was added with powdered seashells in the weight ratio of 4:1:0.5. Six fractions of each mixture were distinctly milled from 1 to 6 h in a planetary ball mill. XRD spectra (broadened and diminished reflections of ilmenite) and FTIR observations (Ti―O―Cbonding) of milled samples indicate the possible incorporation of carbon into the ilmenite structure. Any clues of an occurrence of new rutile peaks were not observed in XRD spectra of milled samples. Consequently, the carbothermic reduction has not been initiated during mechanical activation. In this case, samples powdered for 6 h in a mill were isothermally annealed for 2 h under normal airflow at temperatures of 800 °C, 1000 °C, and 1200 °C, respectively. According to the X-ray diffractograms, the annealing temperatures of 1000 °C and 1200 °C exhibited almost similar trends with rutile (R), pseudobrookite (PB) and elemental iron (F), and a very few ilmenite (I) peaks. Consequently, 6 h of milling and 1000 °C annealing were concluded as the optimum conditions for the carbothermic reduction. Moreover, this study indicated seashells as a potential rate raiser for the carbothermic reduction of ilmenite at 800 °C. Therefore, this process is applicable to upgrade ilmenite into a mixture of synthetic rutile and elemental iron.

Mar 29, 2021

By Thomas C. Ruhe

The Pittsburgh Research Laboratory of NIOSH conducted research to determine the safe operating conditions for using recycled (used) lubricating oil from mining equipment as a partial replacement for diesel fuel to make ANFO-type blasting agents. The use of recycled oil (RO) conserves energy, reduces oil imports, and reduces mining costs. Since RO has a variable composition, there was concern that the additives/impurities it contains may cause ANFO made with RO to be unstable (as compared to regular ANFO) at high summer ambient storage temperatures. Reactivity of RO with zinc was also a concern. Thermal stability tests were conducted to help quantify and resolve these issues. ANFO mixtures (0.66 lb/300 g) were put into sample containers made of steel, stainless steel, and galvanized (zinc coated) steel pipe fittings, which were heated in isothermal ovens. The experimental parameters were temperature settings of 140° F (60° C) and 176° F (80° C), four sample container (pipe fitting) metal combinations, and nominal heating periods of one and three days. The ANFO samples contained 6% each of the following twelve different oils/oil mixtures: No. 1 was diesel fuel, Nos. 2 thru 6 were five candidate oils (2 thru 5 were used oils and 6 was a new synthetic oil), No. 7 was 5% diesel fuel + 1 % graphite, and Nos. 8 thru 12 were 3% diesel fuel + 3% each of the five candidate oils. All samples showed no reactivity when heated at 140° F (60°C). All samples (except No. 7) reacted at 176° F (80° C) in a steel pipe with galvanized caps as follows: No. I reacted most, Nos. 8-12 reacted moderately, and Nos. 2-6 reacted least. All ANFO samples were tested and found not to be cap sensitive.

By E. W. Henderson

Development work in the state of Utah in 1935 consisted of additional work done on wildcat tests started in previous years and on a number of new wildcat tests started during the year. No effort was made to extend areas or to discover deeper productive horizons in proven fields. Principal areas of development were in Daggett County, northeastern Utah; Grand and Emery counties, east-central Utah; and in Washington County, southwestern Utah. Daggett County Clay Basin.—The Mountain Fuel Supply Co. deepened Murphy No. 2, sec. 21, T.3N., R.24E., from 6030 to 6790 ft. for a test of the Sundance formation. Two sandstone members at 6520 to 6644 ft. and 6737 to 6790 ft. contained water. The hole was plugged back to 5860 ft. and left as a future gas supply for the Salt Lake City-Ogden pipe line. The failure of the Sundance formation to produce in this test, in view of the recent Sundance discoveries in Colorado arid Wyoming, was disappointing Emery County Last Chance.—-Thc wildcat test of the Rainsey Petroleum Corporn-tion, Well No. 1-X, sec. 18, T.26S., R.7E., completed plugging back from total depth of 3168 ft. to 2771 ft. and was shut in as a gas well. A gas sand at 2724 to 2771 ft. produced approximately 21 million cubic fert. A deep test of the structure will be started upon approval of a wit plan of development. Grand County Cisco.—-The wildcat test of the Utah Southern Oil Co., sec. 33, T.22S., R.22E., of which the total depth was 1720 ft. on Dec. 31, 1935, is the most interesting operation ill the state. Location of the test was deter-

Jan 1, 1936

(Under this heading will be published notes sent to the Secretary of the Institute by members or other persons introduced by members.) Mining Engineer. Graduate of Colorado School of Mines, 1912, experienced in coal, lead manganese and limestone mining, wishes execu¬tive position. A-2146. Graduate Mining Engineer.-Discharged, reserve officer, age 32, single, 7 years' experience holding responsible executive positions, in iron, copper, and talc mining. Well recommended. A-4913. Mine Manager, Superintendent or Engineer. Age 41, graduate of Michigan College of Mines; 20 years' experience in responsible positions in connection with large operations; in iron, copper, pyrites, lead and zinc mines; successful in finding and developing orebodies, increasing production, and reducing costs. Desires a position with a future. A-4081. Mining Engineer.-Graduate from Polytechnicum, Stockholm; 14 years' practical experience in Sweden, United States, Belgium, and Spain, in iron-ore development, mining, and milling; thorough knowledge of English, French and Spanish; desires position as superintendent or assistant manager. Good references; member; now in Sweden. A-4914. Research Engineer. Now in Chile on the erection of a 50-ton mill with modern machinery for the treatment of Chilean nitrate. Desires connection from the first of next year; with firm operating in South or Central America. A-4915. Metallurgical Engineer. Junior member, age 26, single, graduate Columbia School of Mines; recently discharged as lieutenant in the heavy artillery. A-4916. General Superintendent. Technical graduate, age 35, desires position over a group of four or five mines or as assistant general superintendent for a large. company. Has had experience in superintending mines, construction work, opening new and abandoned mines, safety and effi-ciency engineering and handling organized labor. At present employed by a coal company in the middle West. A-4917.

Jan 11, 1919

By E. W. Henderson

Development work in the state of Utah in 1935 consisted of additional work done on wildcat tests started in previous years and on a number of new wildcat tests started during the year. No effort was made to extend areas or to discover deeper productive horizons in proven fields. Principal areas of development were in Daggett County, northeastern Utah; Grand and Emery counties, east-central Utah; and in Washington County, southwestern Utah. Daggett County Clay Basin.—The Mountain Fuel Supply Co. deepened Murphy No. 2, sec. 21, T.3N., R.24E., from 6030 to 6790 ft. for a test of the Sundance formation. Two sandstone members at 6520 to 6644 ft. and 6737 to 6790 ft. contained water. The hole was plugged back to 5860 ft. and left as a future gas supply for the Salt Lake City-Ogden pipe line. The failure of the Sundance formation to produce in this test, in view of the recent Sundance discoveries in Colorado arid Wyoming, was disappointing Emery County Last Chance.—-Thc wildcat test of the Rainsey Petroleum Corporn-tion, Well No. 1-X, sec. 18, T.26S., R.7E., completed plugging back from total depth of 3168 ft. to 2771 ft. and was shut in as a gas well. A gas sand at 2724 to 2771 ft. produced approximately 21 million cubic fert. A deep test of the structure will be started upon approval of a wit plan of development. Grand County Cisco.—-The wildcat test of the Utah Southern Oil Co., sec. 33, T.22S., R.22E., of which the total depth was 1720 ft. on Dec. 31, 1935, is the most interesting operation ill the state. Location of the test was deter-

Jan 1, 1936

By P. E. Sperry, R. E. Heuer

The United States Bureau of Reclamation is constructing the $200 million Navajo Indian Irrigation Project to irrigate 110,000 acres of land on the Navajo Indian Reservation in northwestern New Mexico. Water from the San Juan River is impounded by Navajo Dam and will be conducted for 26 miles along a series of tunnels and canals to the area to be irrigated. Tunnel No. 3 is the third in a series of six tunnels along the route. Bids for construction of Tunnel No. 3 were received by the Bureau of Reclamation in September, 1970. Fluor Utah was low bidder at $8.7 million. Ten of the 12 bids were based on excavation by tunnel boring machine. The consulting firm of A. A. Mathews, Inc., was retained by the contractor to advise on geologic and rock mechanics conditions after support problems developed in the tunnel. Tunnel No. 3 is 15,264 feet long, has an 18 foot lined diameter, rises approximately one-half inch per 100 feet in the direction being excavated, and is 6,000 feet above sea level. There is one short curve in the alignment. Minimum concrete thickness is 12 inches with eight inches from 'A' to 'B' line making a pay diameter of 21 feet, 4 inches. The tunnel is supported with rock bolts and steel pans. Mole excavation began on May 13, 1971 from a blasted starting chamber. After 46 feet were excavated the mole was shut down and the trailing muck handling equipment was pulled into place. After advancing 1,700 feet in 34 days, unanticipated ground water conditions and ground support problems were encountered slowing moling so that the next 1,000 feet of advance consumed 97 days until December

Jan 1, 1997

By M Colwell

The Coal Mine Roof Rating (CMRR) is a rock (roof) mass classification (RMC) system/index that was originally developed by the United States Bureau of Mines (USBM) for aspects of underground coalmine geotechnical design and was first introduced to Australia as a part of the original Analysis of Longwall Tailgate Serviceability (ALTS) project conducted in 1997/1998. In subsequent years further refinement to its calculation was undertaken, such that the CMRR is now an industry standard for quantifying the structural competence of the primary bolted roadway roof interval and has been routinely/widely used by Australian collieries over the last 25 years with great success for roof support/chain pillar design. There have been many publications discussing the use and calculation of RMC systems and this paper also provides an important update and recommendations in how best to calculate the CMRR. However, it is rare to find an explanation as to why and how a RMC system/index satisfactorily takes account of the mechanics and rock mass behavioural issues associated with ground reinforcement. This paper provides such an explanation and insight with respect to the CMRR so it is: 1) better understood, 2) to allay any concerns, and therefore 3) will continue to be confidently used by and for the collieries’ benefit.

Nov 29, 2022

By Oliver Bowles

A conviction is growing that depressions and other adverse conditions are not entirely unavoidable if a knowledge of past achievements and shortcomings is intelligently, applied in shaping the course of industry. Mineral producers have available a source of such knowledge concerning; their industry in the statistical records of the United States Bureau of Mines, and by scanning, this increasingly exact history can obtain information on which to found a more stable future. This paper contains a brief history, covering more than 50 years, of the activities of the nonmetallic mineral industries as a group, followed by short histories of each of the more important commodities in which are noted the circumstances that lave influenced their development.

Jan 1, 1933

By R. L. Grayson

Using powerful database management software, nested-field analysis and microanalysis of narratives have been made of West Virginia accident data, resulting in a new approach for targeting and prioritizing safety interventions by county, mine size, specific mine, job title, type injury, etc. and combinations of these parameters. The analyses have been useful in focusing training and discussion sessions on specific work problems, trends, conditions, and situations for targeted groups of miners. Application of the technique will be presented in this paper, along with comparisons of various mine performance measures.

Jan 1, 1997

By Carl Belser

Approximately 30 million pounds of tungsten trioxide in the form of ferberite concentrates have been shipped from Boulder County. Since 1940, the production has varied considerably, being affected by the emergency needs of World War II and the Korean conflict. During World War II, attempts to stimulate production were made by the Metals Reserve Company by stabilizing the price for a specified period, the Reconstruction Finance Corporation by small mining development loans, and the Bureau of Mines and the Geological Survey, who cooperatively explored some of the district by surface and underground core drilling. During the Korean conflict and continuing through the first half of 1954) tungsten production was being stimulated by a Government-gauranteed price and by financial assistance loans under the Defense Production Act of 1950 to qualified operators of properties that have merited exploration. This combined program has increased production in Boulder County from about 1,900 pounds in 1949 to an estimated 383,000 pounds of tungsten trioxide in 1953. The 1953 production came from 67 properties. One of the problems confronting producers is the need for improved beneficiaton methods. Ores from the area have not been amenable to flotation concentration and gravity methods have resulted in poor recovery, often less than 70 percent.

Jan 1, 1955