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Teeter-bed (i.e., hindered-bed) separators are used throughout the mineral processing industry for both classification and density separation. The high capacity and sizing characteristics of these units make them ideal for feed preparation prior to coarse flotation (+0.100 mm) circuits. Teeter-bed separators are typically easy to control with two basic operating parameters including fluidization water rate and bed level. However, data show that these two parameters greatly interact with one another. Given this finding, a high-level automatic control scheme was developed and implemented on a full-scale separator. In addition, dialogue with plant operators has led to several simple changes to an already established design that improves operational and maintenance characteristics.

Jan 1, 2010

By Robert L. Vines

"What is past is prologue" - motto of National Archives The question of past, present, and future safety performance in the coal mining industry is not merely an academic one, or one which arises from soul-searching curiosity. It is a question involving pragmatic ramifications, and the answers, or perhaps the public perception of the answers, will have a strong impact on the public policies which influence the course of meeting the Nation's future energy demands. Those of us in the coal industry are keenly aware of the significant impact of the public reaction -- in the form of the 1969 Health and Safety Act -- to -past performance of the coal industry which it found unacceptable. That Act was revolutionary -- and it was expensive. But in finding the industry's past performance unacceptable, the public also recognized its own contributory role through having enjoyed a "buyer's market" forced on a highly competitive industry. One result was to limit the industry's resources and restrict its ability for self-improvement of its safety performance. In acknowledgement of that role, the public picked up the tab for Black Lung disability incurred prior to that time.

Jan 1, 1985

By R. M. Yeates

Public concern over possible degradation of groundwater resources has resulted in an array of Federal laws and corresponding state laws to regulate contaminates from solid and hazardous waste. A mine owner must be familiar with environmental regulations which could impact his operation and must know what precautions and corrective actions to take in order to protect his mining operation from potentially expensive remedial actions. The Environmental Protection Agency (EPA), has issued few regulations controlling the management of mining wastes. Federal regulation of mining came primarily under the Surface Mining Control and Reclamation Act (SMCRA) administered by the Office of Surface Mining (OSM). Waste generated from the extraction, benefication and processing of ores and minerals was exempt from regulation under the Resource Conservation and Recovery Act (RCRA), which is EPA's major instrument in controlling surface contaminates. On December 31, 1985, EPA submitted to Congress a report entitled "Wastes from the Extraction and Benefication of Metallic Ores, Phosphate Rock, Asbestos, Overburden from Uranium Mining and Oil Shale", which will be referred to, henceforth, as the Congressional Report. This Congressional Report assessed the possible adverse effects of mine associated wastes. This report is the first step toward developing regulations with which EPA can regulate waste from the extraction, benefication and process of mineral ores.

Jan 1, 1987

By H. T. McAdams

The logic of regression analysis as an operations research tool is critically examined, and a formal basis for its application to mining problems is developed. The traditional view of regression analysis as a statistical discipline does not provide an adequate basis for evaluating a regression model in a specific area such as ore reserve calculation or process control. In particular, the validity of the residual-sum-of-squares criterion is questioned, and the need for a criterion based on interpolative features of the model is emphasized. Strictly speaking, a regression model is statistically supported only at points at which observations are available, yet inferences are drawn with regard to a continuum. When considered as a mathematical function, therefore, the model is observationally defined only on a domain consisting of a finite number of points. Extension of this domain to an interval of the real line must be based on physical rather than statistical argument. Vector space and function theory concepts useful as a logical framework for a physically oriented problem analysis are discussed and their usefulness demonstrated in a practical problem.

Jan 1, 1966

By Francis F. Pitard

The presence of elements, minerals, or chemical compounds in materials at very low concentrations is becoming a constantly increasing concern for several segments of the Industry. Some trace elements or chemical compounds may be considered as hazardous, some are simply considered as undesirable In complex processes where they could be constantly recycled and end up as the major factor of decreasing quality for some valuable products. In some other cases, the presence of a trace element or mineral may be highly desirable because of its economical value: precious metals are falling into this category, they probably were the first trace elements to draw our attention. Tremendous quantity of money is spent for analysis at the trace level, also the analytical "tool" has been considerably improved during recent years, but still the sampling aspect of the problem remains obscur for many, and because of it, large quantity of analytical efforts become meaningless. Not only the absence of sampling strategies is badly affecting the representativeness of a large majority of samples, but furthermore for the same reasons, many laboratories are failing In their endeavor to prepare reliable standard reference materials. The reason of this failure has its roots in the unability to estimate effectively the sampling characteristics of the element, mineral, or compound of interest, not to mention the unability to perform precise and accurate complete analysis, so essential for the instrumental analyst (1). In this paper a strategy to perform a better sampling operation is recommended. SELECTION OF A PROBABILISTIC APPROACH AS SOON AS PRACTICALLY POSSIBLE It Is essential to differentiate probabilistic sampling from non-probabilistic sampling. As Illustrated in Figure 1, the sampling operation Is a selection process which could be performed In two different ways: I. A probabilistic selection process according to which all elements of a lot of material to be sampled are submitted to the selection with a same probability of being selected. 2. A non-probabilistic selection process according to which all elements of a lot of material to be sampled are submitted to the selection with different probabilities of being selected.

Jan 1, 1986

By Ed Ramsay

The Hill is a cyanidation plant with flotation and roasting. The grinding and treatment have at the present time a capacity of 1400 tons of ore per day and the precipitation has a capacity of 6000 tons per day. The ore is delivered by a 36" conveyor belt and tripper to 8 mill bins having a capacity of 6000 tons. The ore from these bins is discharged onto 20" gathering conveyor belts which are regulated with p.i.v. speed changers to control the belt weight. A weightometer determines the tonnage milled. The feed enters the 8' x 12' rod mill through a rubber lined chute and the product is discharged through a launder to a 7' rake classifier in closed circuit with 10' by 6' hardinge ball mill. Lime slurry is added at the rake classifier to give a strength of .30#/ton. The classifier sand is fed into the ball mill with a scoop feeder and the mill discharge flows in a launder back to the classifier. The classifier overflow is pumped to a 24' by 12' bowl classifier in closed circuit with a 8' by 15' regrind mill. The bowl classifier sands are fed to this mill and the mill discharge is pumped back to the bowl. The bowl overflow at 8% - 200 mesh is the final product from the grinding circuit.

Jan 1, 1975

By Hongjie Yu, Rakshith Shetty, Claudio Cimiotti, Nick Karlin, Mike Mooney, Vitaly Proshchenko, Matt Kendall

This paper documents an effort to explain cutterhead torque behavior observed during slurry pressure balance TBM tunneling through soft ground on the Los Angeles Clearwater project. AI machine learning and mechanics model-based learning was used to characterize cutterhead torque behavior including the TBM operating and ground parameters that influence cutterhead torque. Also, key parameters were from the slurry circuit data, including fines content, in-situ density, pore water fraction and solids content were included. The paper details what was learned using these new data-driven approaches as well as limitations with AI machine learning.

Jun 23, 2024

By T. K. Kim

Iron, cobalt, and nickel in waste ferric chloride solutions were separated from each other by solvent extraction. The iron was extracted from the cobalt and nickel by the use of methyl isobutyl ketone, and then the cobalt was separated from the nickel by the use of a high-molecular-weight quaternary amine dissolved in a solvent of high aromatic content.

Jan 1, 1980

By R. W. Draves

Planning and testing in advance of the mining operation are essential. This advance work can involve physical and chemical analysis of overburden cores, field test plots, green- house studies or any of a multitude of other baseline data collection activities. This paper presents the results of Central and South West's field test plots and how they relate to topsoil substitution. Besides the obvious need for testing in advance of mining, there are the inevitable regulatory requirements. Quoting from the office of Surface Mining Regulations concerning topsoil substitution: 216.22(e) TOPSOIL SUBSTITUTE AND SUPPLEMENTS -Selected overburden materials may be substituted for or used as a supplement to topsoil if the office determines that the resulting soil medium is equal to or more suitable for sustaining revegetation than is the available topsoil and the substitute material is the best available to support revegetation.

Jan 1, 1985

By Ted Klemetti

Roof deterioration in weak moisture-sensitive rock leads to roof falls in coal mines. An observation site was set up in intake air at an underground coal mine in central Ohio to evaluate the time-dependent deterioration of moisture-sensitive roof rock. By periodically collecting and weighing the rock falling from the roof, the National Institute for Occupational Safety and Health (NIOSH) was able to quantify the deterioration of the moisture-sensitive shale roof. The measurements showed that more roof rock is falling in the dry winter months. Movements in an intersection were monitored in order to determine if deformation correlated with seasonal changes in temperature and humidity. The rate of intersection roof-to-floor convergence was found to be cyclical and related to seasonal changes, with more convergence during the months of April through September. At the study site intersection, the roof beam did not show deflection indicating movement most likely due to mine floor deformation. The bolt load also increased in the warmer months before shedding load, possibly due to rock failure. Temperature and relative humidity sensors, placed in holes in the roof show that mine air does not mix with the air in the holes. Consistent saturation levels of relative humidity were measured in the holes and it appears that high levels of moisture may have migrated into the bolt holes from roof shales. A roof sealant applied to a portion of the test roof appears to be preserving the roof and reducing the amount of rock fall into the entry, while the screened area virtually eliminated rock falling from the roof.

Jan 1, 2009

By Cleophus Short

[Of the many occupations in and about the coal mines, those of the haulage crews are among the most hazardous. Statistics ship that the second greatest number of fatalities about the coal mines occur during haulage ion and through the use or misuse of haulage equipment. During the five year period between January 1, 1957 and January 1, 1962, the m stone mine had a. Sack haulage frequency of 4098 and mined 3, 541,939 toads per haulage fatality. Coal mire haulage is similar in respects to railroading. We gee very serious consideration to the instillation of tack and to the selection of the haulage crews. In doing this, we are attempting to have our coal mine haulage as. Safe as that of the railroads.]

Jan 1, 1963

By Moussa Wone, V. Nasri, F. Guimbal, D. Andre

The Magenta underground station was constructed in the heart of Paris in saturated soft soil and at shallow depth. To investigate the surface settlement and the deformation of the concrete liner, innovative techniques combined with a vast campaign of monitoring were applied. The monitoring data and a simple three-dimensional ?nite element analysis were used to assess the accuracy of the two-dimensional ?nite element model originally utilized in the design of the station. The deformation of the concrete liner was monitored using vibrating wire extensometers. Their performance was validated by the data obtained from monitoring and also by a simpli?ed ?nite element analysis.

Jan 1, 2003

By D. N. Madge

A survey is given of production scheduling systems currently in use or contemplated for future use in Cominco operations. Emphasis in this presentation is made on the chain of decisions that are made with the help of mathematical programming models. Some attention is devoted to the structural properties of the models.

Jan 1, 1966

By R. E. Coleman

Infrared spectroscopy, employing the internal reflection method in conjunction with solvent extraction techniques, was used to study surface reactions between aqueous potassium ethyl xanthate and both sphalerite and precipitated zinc sulfide each activated with aqueous copper sulfate. It was determined that reactions occurring on the sphalerite and zinc sulfide surfaces produce the reaction products ethyl dixanthogen and cuprous ethyl xanthate, some of which are ad¬sorbed on the mineral surfaces. According to infrared spectra showing the reaction to form these compounds, the ratio of cuprous ethyl xanthate to ethyl dixanthogen adsorbed is directly related to pH of the flotation solution.

Jan 1, 1967

By M Aboagye, K Appau, W. Assibey-Bonsu, C. Muller

A case study based on two recoverable resource modelling techniques (indirect and direct or localised methods) have been derived using typical feasibility study or new mine drilling data configurations from the extensions of an existing mine’s massive production database. The database is from the Gold Fields Tarkwa Gold mine (~6Moz Mineral Reserves and 13-year Life-of mine). The corresponding recoverable resources from the various techniques are then analysed using the open pit Whittle optimisation process. The results were then compared based on the Whittle optimisation results to determine the efficiencies of the approaches and the validity of the recoverable mineral resource estimates for mine planning and financial forecasts (including Cash Flows etc). Based on historical production metal recovery, the paper also assesses the corresponding orebody and mine planning as well as financial risks with regards to the modelling techniques. The study shows that the localized direct and somewhat more straight forward approach if applied efficiently can provide an equally useful tool for computing recoverable resources for mine planning and financial forecasts, as compared to the indirect approach as presently in use.

Jun 25, 2023

By Salim Akhtar

The operation of a mineral processing plant with a complex flowsheet is represented by a mathematical operator. Such a representation permits a quantitative evaluation and monitoring of the separation processes in different sections of a processing plant, and gives an overall separation efficiency of the plant.

Jan 1, 1973

Underground mining has the potential to be one of the more dangerous industries in the United States and the world. Following recent disasters in Sago, WV; Darby, KY, and Crandall Canyon, UT, the mining industry was reminded of the need for a system to allow trapped miners awaiting rescue to survive following a disaster. To address this need, Battelle has developed a Mine Barrier Survival System (MBSS) that surpasses all current technologies and sets a new standard for keeping miners alive in the event of a fire, flood, explosion or collapse. The MBSS creates a temporary refuge for miners who cannot escape by using inflatable barriers and a post-fire atmosphere scrubbing system to define the ?safe haven? and remove CO2 and CO while replacing oxygen and providing heat. Current personal-protective systems in use are designed to provide breathing air for only a few hours when, realistically, it may take days for rescue teams to reach trapped miners. Battelle?s MBSS is designed to aid up to 15 miners for four days.

Jan 1, 2008

By Donald H. Dowlin

The design of a preparation plant for minimum maintenance and clean up requires both the skills of the Engineer and the practical experience of the Operator. From the initial flow sheet and preliminary design until the plant is completed and operating, each phase of the work must be thoroughly explored for simplicity, workability and high efficiency. It is the responsibility of the Designing Engineer to develop the plant around the basic flow sheet, selecting equipment and materials not only with regards to Initial cost but also required upkeep and repair.

Jan 1, 1962

By S. C. Schmelter

The destabilizing effect of water pressure on rock mass stability is examined quantitatively by the finite element method. A coupled code that accounts for the simultaneous effects of rock mass deformation and transient fluid flow is used for this purpose. The traditional soil mechanics assumption of an incompressible fluid is shown to be untenable for the analysis of porous, fractured rock slopes. A Mandel-Cryer effect, a transitory but elevated and potentially destabilizing water pressure following a cut, was not observed.

Jan 1, 1997

By V. L. Magnus

The text of this chapter was not received in time for printing.

Jan 1, 1979