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By Kyle Amoroso, Larry Applegate, Aaron K. McCain

The use of frozen soil as ground improvement and temporary ground support for the excavation and construction of cross passages and adits has gained in popularity over the last decade. Frozen soil provides a number of advantages for this application such as being waterproof, structurally stable, and working well with any soil type. One of the greatest advantages is the ability for the system to be adaptable to the project geometry and site limitations. Multiple case histories illustrate that freezing can occur from the ground surface, from within the tunnel, or as a combination.

Jun 13, 2023

By R. A. Paul

WIDCO, operator of the Centralia Coal Hine, chose dredging, a method not commonly used for overburden removal, as the fastest, safest, and most economical method for mining through an alluvial filled valley. Now that the work has been completed, how did the cost and schedule compare with the original estimates? What would we do different next time in preparing for a dredging contractor? What are the potential pitfalls working with a dredging contractor? Would we do it again? When should dredging be considered as an overburden removal option?

Jan 1, 1989

The following list is a representative sample of the types of software available to the mining industry. For additional information concerning software packages for your minicomputer, contact equipment manufacturers or software suppliers.

Jan 11, 1981

By R. Flattery, Z. Agioutantis

Coal and rock pillar design is critical not only for mineral extraction but also for the safety of the mine operators. Pillar strength can be estimated through numerous empirical formulas that are available in the literature, which are typically based on a statistical analysis of case study data. The limitation of most of these equations is that they only considered the width to height ratio and in situ rock or coal strength for pillars in horizontal seams. The adoption of such equations to estimate pillar strength in inclined seams may overestimate the pillar strength and ultimately lead to a poor pillar design. This paper will discuss different techniques that can be used to estimate pillar strength in inclined seams as well as present preliminary modeling results for stress redistribution around inclined pillars. Factors in the parametric analysis include pillar shapes, geometry, and seam inclination.

Mar 2, 2022

Many investigators believe that column flotation cells offer significant advantages over standard mechanical machines for the flotation of fine particles. However, because of their unique design and operation, conventional techniques for flotation cell scale-up and design cannot be applied to columns. In an attempt to help alleviate this problems a population balance model based on first principles has been developed for fine particle flotation in a column. Two different terms have been considered in the model, i.e., transport and rate. Transport terms, incorporating fluid flow and bouyancy, are used to describe the movement of air bubbles, unattached particles and bubble-particle aggregates along the length of the column. Rate terms, which describe the bubble-particle attachment process, have been derived from first principle considerations. Because the model is based on first principles, it can be useful for the design, control, optimization and scale-up of column flotation cells.

Jan 1, 1987

By Donald H. Sargent

This paper focuses upon the changing character of the market for Western bentonite, and upon transportation methods and costs affecting this market. The basis for the data in this paper, in addition to public sources of information such as federal and state government agencies and the open literature, was a program of 57 face-to-face interviews with individuals knowledgeable in the bentonite production, consumption, and transportation industries. The study was performed in 1974 and 1975 by Versar Inc., for the Bureau of Land Management, Department of the interior.*

Jan 1, 1979

By James McMaster

The Kamyr Countercurrent Tower Leaching Process is intended to combine, in a single tower, thickening, leaching, separation and clarification of pregnant solution, and washing of leaching chemicals from the tailing pulp. For a gold or silver metallurgical plant, the flowsheet would consist of crushing and grinding, cyclones for size control and partial thickening, the Kamyr tower, and a gold or silver recovery system of either carbon in solution, zinc precipitation, or direct electrowinning. Ancillary systems for the Kamyr metallurgical plant would include cyanide preparation, fiber preparation and recovery, and flocculant preparation.

Jan 1, 1990

By Terry McNulty

There are many potential pitfalls in the commercialization of innovative technology, and the failures often are remembered longer than the successes, thereby serving as deterrents to subsequent attempts. Given the dependence of the mineral industry's future on effective innovation, it is essential that we understand the causes of failure. Case histories are presented and the out- comes are analyzed in terms of the driving forces for innovation and the steps taken during development. Industry's current attitude toward and capacity for technological innovation are discussed, and a methodology is suggested for predicting successful innovation.

Jan 1, 1998

By Jean Paul Duterque, Morris J. V. Beattie

In many parts of the world, pyrite and arsenopyrite occur together in sulphide ores either as the only sulphide minerals or in conjunction with other valuable sulphides. It is desirable to produce separate concentrates of the various sulphide minerals, including pyrite and arsenopyrite, so that the contained desirable metals can be recovered economically. It is common, for instance, for gold in an ore containing both pyrite and arsenopyrite to be associated almost exclusively with the arsenopyrite. It is desirable in this instance to produce an arsenopyrite concentrate for gold recovery while rejecting the barren pyrite.

Jan 1, 1992

By Thor Skjeggedal

The Norwegian contracting firm A/S Høyer-Ellefsen has for the last 2.5 years carried out substantial pregrouting in a 7600m long tunnel just outside the city of Oslo. This has been done to avoid groundwater lowering and consequent damage to surface structures. A WIRTH TBM is used in combination with a 2 boom Atlas Copco hydraulic jumbo for the drilling of groutholes in front of the machine. The detailed procedure for the drilling and grouting will be discussed, and the results obtained will be presented.

Jan 1, 1981

By H. T. Mulryan

Talc is used as an essential ingredient in a variety of plastics applications ranging from polyester body patch compounds through polypropylene automotive, appliance and household furniture components to high performance parts made from liquid crystal engineering resins. This paper focuses on polyolefin applications, the three-tier market for talc in polypropylene, the effects of various tales in typical compounds and trends in each market segment. Emphasis is given to emerging markets, examples of which are polypropylene compounds that mimic higher cost resins, and polyethylene films. Customer requirements, for tales for these purposes are discussed.

Jan 1, 1993

By Fathi Habashi

CLAYS CONTAIN the mineral kaolinite, a hydrated aluminum silicate. It is an important potential raw material for aluminum, especially for those countries possessing no bauxite deposits. Therefore, there is no surprise to find a large volume of research done for the recovery of aluminum from clays. Kaolinite (Al203?2 SiO2?H20) contains 39.8% A1203; 46.3 % SiO2, and 12.9 % H2O. The analysis of a good-quality dried clay of an Eastern Canadian siliceous shale is shown in Table 8-1.

Jan 1, 1970

By M. E. Gershon

An approach for scheduling the mining of ore and waste blocks in a surface mine is presented. While mathematical programming approaches have been developed to solve this problem optimally, they are difficult to implement and understand. The more simplistic approach presented here achieves practical mining schedules, taking into account both long- and short-term considerations. The key to the approach is use of the concept of ranked positional grade. The program can determine a complete schedule for a specified time period, or it can be used interactively as a guiding tool for the engineer.

Jan 1, 1988

By H. T. Mulryan

Talc is used as an essential ingredient in a variety of plastics applications ranging from polyester body patch compounds through polypropylene automotive, appliance and household furniture components to high performance parts made from liquid crystal engineering resins. This paper focuses on polyolefin applications, the three-tier market for talc in polypropylene, the effects of various tales in typical compounds and trends in each market segment. Emphasis is given to emerging markets, examples of which are polypropylene compounds that mimic higher cost resins, and polyethylene films. Customer requirements for tales for these purposes are discussed.

Jan 1, 1994

By S. B. Bhagwat

Before the Clean Air Act Amendments of 1990, coal policies-especially coal research policies-were geared to find a solution to the sulfur emission problem. However, technologies to reduce sulfur emissions cannot be tailored for a single coal. A technology that will clean Illinois coal to compliance levels will do the same, or nearly the same, for most other types of coal. This paper will discuss an integrated approach to the analysis of the future of coals from different regions in the United States and its implications for coal-related policies by government and industry.

Jan 1, 1994

By L. W. Saperstein, MJ. Carlson

With the goal of improving the strength characteristics of pneumatically emplaced material used for localized subsidence control, the binding additives fly ash, bentonite, and portland cement were examined for their effect on the support capabilities of coal refuse. It was found that, within certain concentration ranges, all three offered some increase in the ultimate strength of the backfilling mixture. However, portland cement gave the greatest percentage increases. Selection of the appropriate backfilling mixture will allow for the most economical and efficient subsidence control when pneumatic stowing is employed.

Jan 1, 1990

By Greg Barfoot, K. Payne

Condition monitoring of conveyor belting has become an established tool for maintenance programming, replacement strategies and quality assurance for belt conveyor systems. What is less well known is that the condition of the conveyor belting is usually a symptom of problems in other areas rather than the problem source. This paper presents an overview of the state of the art in belt monitoring and the move towards on-line NDT systems. The use of belt monitoring data as an indicator for overall system design, maintenance and operation is also discussed.

Jan 1, 1996

By A. S. Polubinsky, V. P. Chernyak

A further development of the theory of heat- and mass transfer in the system “strata - mine opening" is necessary for an improvement of the existing technique of heat calculation of mines and other underground constructions. A generalized boundary problem of heat- and mass conduction in strata around an opening as a theoretical ground for that purpose and several particular situations, important from the point of view of an opening and surrounding strata heat state analysis, as well as results of numerical experiments executed for such analysis are presented.

Jan 1, 1997

By Paul D. Chamberlin

The evolution of heap and dump leaching has followed the development of agglomeration, materials of construction for leach pads and ponds, solution distribution systems, testing techniques, and state regulations. They are now mature processes. Possible future directions and developments are discussed. In situ leaching of precious metals is waiting to be commercialized. Regulators are reluctant to allow the use of cyanide because of the potential for excursions and operators are reluctant because of the potential for lawsuits. Developments in alternative lixiviants are needed before in situ leaching is accepted.

Jan 1, 1989

By Robert F. Conley

This paper describes attrition milling as exemplified in rotary and vibratory mills for ultrafine grin¬ding application Without attempting to narrate the differences between various devices, generalized differences between the broad categories of rotary and vibratory milling are presented and compared with the ball mill Applications of these mills for coal, limestone, kaolin, mica, talc and iron oxides are described giving specific differences of the mineral properties that affect their behavior in the grinding mills Where applicable, specific recommendations are provided for ultrafine grinding of various industrial minerals

Jan 1, 1983