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By G. D. Hood

The U.S. Bureau of Mines investigated rapid froth flotation through the use of more efficient bubble-particle collisions that improved the overall flotation kinetics. An in-line static mixer efficiently mixed the air bubbles, water, and ore, rapidly attaching the hydrophobic mineral to the bubble surface. As the mixture entered the flotation chamber, the hydrophobic mineral was already attached to the bubbles and was quickly floated away from the remaining ore pulp. A rougher concentrate containing 4.5 pct copper was obtained from a western porphyry copper ore containing 0.67 pct copper. Over 99 pct copper was recovered from the ore at a rate 7 times faster than conventional flotation.

Jan 1, 1991

By F. W. Davis

SOME idea may be gained of the tremendous consumption of refractories by the open-hearth steel manufacturers from a statement made by A. T. Green at a meeting reported by T11.e Industrial Chemist of London, as follows: "At a very progressive steel plant in the Midlands, with a battery of five open-hearth furnaces working. twelve months and making 3000 tons of steel per week, the cost of refractories per ton of steel produced averages about $0.50 for the actual open- hearth casting and $0.12 for those operations incidental to the rolling of the metal." .These figures, when translated into the annual tonnage of steel, represent a very considerable expenditure.

Jan 1, 1930

By B. L. Bessinger

Because of a, work stoppage at the Carlsbad plant, IMC faced the challenge of operating a 24-hour-a-day mine and plant with inexperienced maintenance and production crews. This is an underground mining operation, using the room-and-pillar mining- method. The mine was entirely, mechanized with conventional equipment, was hoisting an average of 13,539 tons off ore per 24 hours, and employed a, mine maintenance group of 100 men. The 100-man, mine maintenance group was equally divided between mechanics and electricians. In re-forming this maintenance group, two main objectives were to be achieved (1) a general upgrading off the intelligence level; and (2) the elimination of craft lines for greater flexibility.

Jan 1, 1966

By T J. Wilton, K A. Broadhurst

The United Kingdom, although a relatively small island, has a wealth of mineral deposits, coal, granite, limestone, gypsum, lead, florspar, etc. Coal is a major source of energy with 71 opencast coal sites, 52 using explosives. Many of these sites are in rural areas, the average area worked being 250 acres. The smallest is 35 acres, the largest 2,000 acres, but only 600 acres can be operated at any one time.

Jan 1, 1981

By Elton L. Litchfield

The techniques for direct initiation of detonation, developed by the Bureau of Mines, have been applied to gaseous mixtures of oxygen with methane, 'thane, propane, butane, or hexane. An exploding wire was used as the initiation source to determine minimum stored electrical energies required to effect detonation of mixtures between one-half and two times the stoichiometric fuel ratios. Detonations were obtained in the most easily initiated mixtures of ethane, propane, butane, and hexane for initiation energies between 24 and 33 joules at 1 atm and 28-43 joules at 0.5 atm initial pressure. Methane mixtures, at 1 atm, were not observed to detonate when initiated with up to 484 joules.

Jan 1, 1966

By A. F. Symonds

The effects of harmonic resonance between the supply impedance and power factor correction capacitors on systems with large harmonic sources, such as mine winders, are well known. The similar effects of resonance with cable capacitance are not commonly encountered and, hence, are not always considered in the design of medium-voltage networks. This article considers some of the aspects of resonance between the supply impedance and the cable capacitance and presents one successful approach to solving the problem.

Jan 1, 1998

By G. Davis

It is well known that anticipated mineral prices can have an overwhelming effect on a property's expected value. However, price movements throughout the life of a project also affect value. Thus, it is necessary to not only estimate the expected commodity price at the start of a project but also the manner in which that price is likely to fluctuate throughout the project's life. This paper provides a simple method of incorporating mineral price movements into mineral project valuations.

Jan 1, 1997

By Heinrich Schubert

In many unit operations, there are more or less developed turbulent flow conditions. Then, macroturbulence influences the transport phenomena of the particles and microturbulence controls the stresses acting on fluid and solid particles or agglomerates as well as the collisions between particles. Consequently, these conditions have to betaken into consideration for modeling and optimization. The results of corresponding approaches are demonstrated taking classification and flotation as examples. But, at present, extensive simplifying assumptions have to be made.

Jan 1, 1989

By Moore A. J

Control of blast vibration requires that its nature and causes be understood, and that effective control procedures be implemented to ensure compliance with limits related to the probability of damage to buildings/structures and human discomfort. This paper covers measurement equipment, assessment and prediction techniques, blast vibration control procedures and applicable statutory limits. It reviews current practice, and provides information on recent developments in blast vibration measurement equipment and control techniques, using examples based on Hunter Valley mining practice.

Jan 1, 1995

By ALEXANDER L Hay, Alexander L.

THE Sydney coal field, the largest and most valuable in Nova Scotia, is on the northeastern coast of the Island of Cape Breton, extending from Mira Bay on the south to Cape Dauphin on the north, a distance of 30 miles, and has a general dip northeast under the sea. The field embraces the mining villages of Morien, Birch- grove and Reserve and the towns of Dominion, Glace Bay, Waterford and Sydney Mines. The city of Sydney is about midway between the northern and southern extremities of the field and on the western fringe of the productive coal measures. Sydney harbor crosses the coal field, cutting off direct rail connection between Sydney Mines and the greater part of the field to the southeast.

Jan 1, 1928

By S B. Richardson, R E. Danell, D Mead, N T. Moxon

Explosives provide a very concentrated source of energy which is often well in excess of that required to adequately fragment the surrounding material. Blast design, environmental requirements, production requirements and the lack of detailed insitu geological data generally limits the degree to which the explosive energy distribution within the blasthole can be significantly altered using, for example, different explosive formulations or variable loading techniques. However, increased flexibility can often be exercised over a blast through the use of air-decks.

Jan 1, 1993

By Mary Sue Coates

Characterization of the rock mass in which deep underground structures are to be located is of critical importance to the feasibility and design of the structures. The process involves areal studies, subsurface exploration and extensive testing to obtain comprehensive data on the rock units which will enclose the excavated structures. The Illinois Deep Hole Project provides an example of characterization of rock at great depth describing the types and variety of tests and studies which were utilized and the results obtained.

Jan 1, 1984

By Patricia Dillon

EHS Management Standards Communication and Reporting (8) ! Establish processes for internal and external communications ! Designate responsibilities for communication with COI ! Report as defined by senior management ! Report annually to employees, shareholders, COI on EHS and social performance Community Rights and Public Consultation (9) !Identify COI?s and establish process to hear concerns !Acknowledge and respond to complaints !Support local communities !Plan for closure and conduct public consultation !New projects include identification of COI?s, concerns to be considered in design

May 1, 2004

By Pekka S. Särkkä

The method of interactive dimensioning is based on the computation of the loading-deformation curves caused by country rocks on the pillars with numerical methods. The comparable loading-deformation curves of pillars with different shapes are determined with small-scale model tests in a servo-controlled testing machine. The equilibrium points, i.e. the stability of the different pillar-country rock systems are determined by matching these curves adequately scaled. A case from a Finnish mine is presented together with the stoping results.

Jan 1, 1984

By Luke K. A

Pressure on production at New Zealand China Clays has led to the development of a dewatering control loop for fine halloysite china clay. The development was based on the analysis of data from the automation of plate and frame filter presses. The analysis of the data has led to process changes, and the ability to quickly solve dewatering problems. As a result of control in the dewatering circuit press times have reduced on average 117% and output has increased proportionally.

Jan 1, 1989

By Grazyna Zakrzewska-Trznadel

The paper outlines the main objectives of the project that concern the evaluation of the possibility of uranium production from indigenous resources since Poland enters the nuclear program. The best available technologies are considered for uranium extraction and obtaining the yellow cake - U3O8. Liquid-liquid extraction with novel extracting agents, as well as membrane processes for separation of by-products will be tested in course of the project. The technological part will be completed with techno-economical analysis. Acknowledgement The studies were supported by the POIG project, No 01.01.02-14-094-09-00 ?Analysis of the possibility of uranium supply from domestic resources?.

Aug 1, 2010

By J. T. Ryan

SAFETY practice or the elimination of accidents in our coal mines is specifically a problem of management. It cannot be delegated to any governmental agency except that the various coal-producing states do and should have some minimum safety standard laws. However, the legislative method of attempting to control mine accidents is ineffective because of the delay between the necessity and the action. It will always be impossible to keep our various state mining laws up to date; and when the law says you must do a certain thin there is a tendency to do this and no more. Unless the scheme for setting up state regulations is so flexible that when a new hazard develops it can be immediately and adequately covered and the whole responsibility for accident elimination placed undivided on the

Jan 1, 1937

By Ben Cottrell

In this paper technical drilling is referred to as the process of collecting engineering and metallurgical parameters for subsequent mine design considerations. Throughout the development of a mineral exploration property there are various opportunities to ?piggy-back? technical drilling onto the routine exploration drilling process, helping to reduce future costs and delays associated with re-drilling and missing information. This article is written from the engineers and metallurgists point of view, to outline some best practices for exploration borehole planning and technical data collection requirements.

Aug 1, 2013

By Gostylla W

The economic feasibility of controlled district cross-cut recirculation is examined in this paper with particular reference to the most important mine ventilation network parameters. An algorithm is developed to express the annual cost of recirculation which is then compared to the annual cost of conventional ventilation using the University of Queensland Experimental Mine as a case study. The concepts of resistance ratio and volumetric efficiency ratio are introduced and used to analyse the economic feasibility of controlled recirculation within a mine ventilation network.

Jan 1, 1988

By Irwin Roman

The literature of geophysics as applied to the discovery of mineral deposits has been very extensive during the past few years,' but there seem to be few references to the use of the method of least squares for obtaining better interpretations of the observed data.2 There seems to be a general reluctance among geologists and engineers to acquire the technique of least squares, in spite of the fact that a thorough knowledge of the theory is not necessary for the use of the method.

Jan 1, 1932