Search Documents

By Thomas F. Clemens

This paper covers various changes in government regulations, taxation, and legislation for the past two plus years and the up- coming one. Part of the paper will discuss recent business conditions and how they have affected the cement and lime industry.

Jan 1, 1983

By Michael J. Fiannaca

Disseminated epithermal gold metallization occurs within a breccia unit interpreted to be a submarine debris flow. Cold is associated with oxidized pyrite, fluorite, and jasperoidal silica. A minimum of 9 million tons of open-pittable mining reserves will be cyanide heap leached as run-of-mine ore at a rate of 1.0 million tons per year. Careful evaluation of the combined results of successive sampling projects has established the pit plan, mineable reserves, and process metallurgy of the operation. The sampling procedure utilized for a given test depended upon geological interpretation as well as the procedures, successes, and failures of previous tests. This paper summarizes the sampling and testing procedures of the development effort in light of the project goals and attendant problems in achieving them.

Jan 1, 1984

By Bruce Watzman

Can the United States mining industry achieve its long-stated goal of zero fatalities ? and what will it take to do so? Does it require new laws and regulations, as some propose, and a continuation of the commandand- control model that has been born out of more than 40 years of regulation and enforcement under the Federal Mine Safety and Health Act of 1969? Or, is it time to consider a new model to manage safety and health and drive continuous, sustained improvement? These are questions that many are debating as mine safety performance, while improved, appears mired in a trough where improvement followed by declines seems to have become the rule rather than the exception. Without doubt, U.S. mines have made significant progress in safety performance during the last four decades, yet the stalled decline in fatality numbers, the industry?s report card of its success or failure, has led some to question whether the industry will achieve zero fatalities in U.S. mining by relying solely on the Mine Act?s framework and implementing its regulations. These are questions the CEO-led task force, set up by the National Mining Association (NMA), considered as it sought to identify impediments to zero fatalities posed by the current regulatory regime. Out of that effort came CORESafety, a common safety and health framework that relies on a management system approach to improve safety and health performance. The goal of CORESafety is to achieve zero fatalities and a 50-percent reduction in the rate of injuries in U.S. mining within five years ? 0:50:5. CORESafety is built on the plan-do-checkact model, which has been successfully deployed by industries, mining and nonmining alike, to drive continuous improvement in safety and health performance. The improvements in safety performance that can be achieved by shifting from a command-and-control regulatory approach to a risk-based systems approach built on the plando- check-act model have been documented in numerous industries. For example, the United Kingdom quarrying industry (Fig. 1), not satisfied with the number of reportable accidents being experienced 1995-2000, established a hard target of a 50-percent reduction in the number of reportable accidents during the period 2001- 2005. Having met this target, the industry then established a further target zero for the period 2006-2010. The mechanism to achieve these reductions? The plan-do-check-act model.

Jan 1, 2014

By Carl R. Peterson

The Rapidex continuous drill and blast tunneling concept utilizes a unique spiral blasting pattern that permits efficient performance with relatively small single shots, while at the same time directing major blast fragments at right angles to the tunnel axis. The concept's self-shielding geometry permits the design of a lightly shielded machine that can stay at the tunnel face firing frequent small blasts to provide rapid, virtually continuous advance. This paper describes Phase III of the development program (supported under Bureau of Mines contract H0252047) in which the "front end" of the machine?drilling loading, and shooting components, together with the shield--was fabricated and field tested underground at the White Pine Copper mine, Michigan. One of the major accomplishments of the Phase III effort was to develop a fully remote controlled loading and initiation system in which explosive slurry is pushed, through a hose into the blasthole by a small water-driven piston carrying the blasting cap. The cap is ignited via an induction coil just prior to entry into the borehole, after which a delay permits complete -withdrawal and shielding of the loading hose. The ultimate objective of the present Bureau-sponsored program is to evaluate the feasibility of mechanizing hard rock mining operations, such as development to a point where drilling, loading, shooting, and mucking can proceed simultaneously and result in increased productivity.

Jan 1, 1977

By George Joseph Malina

Contractor chose and Owner allowed concrete to be placed using the arch first principle while excavating the 35'-3" O.D. rock tunnel. The contract included excavating and lining 26,000 L.F. of rock tunnel to 33'-I.D. Concrete was placed at a rate of 90LF per working day using a movable bridge to allow batching, mixing and pumping of concrete adjacent to the tunnel form.

Jan 1, 1981

By Yang Song, Li Shaokang, Wang Zhiqiang, Wang Jinjun, Li Guofeng, Su Meixuan

CaCO3, as a component widely existing in natural minerals, is a common impurity. In recent years, triboelectric separation has been applied to the separation of minerals containing CaCO3. However, the CaCO3’ s tribocharging mechanism is still unclear and the charging effect of CaCO3 is not obvious. In order to study the effect of triboelectric charging of CaCO3 particles under different conditions, according to the single particle frictional collision charge-mass ratio formula derived from the condenser model, an experimental platform for particle tribocharging was built in this paper. Then, the formula of charge-to-mass ratio (Q/m) was derived based on the analysis of the particle force. Particle image velocimetry (PIV) was used to record particle motion trajectories to calculate the Q/m of one particle by this formula. In the experiment, the airflow velocity, tribocharge material, and moving distance of the particles were varied to investigate the variation of the particle charge-mass ratio results. The results show that CaCO3 was negatively charged when tribocharging with mental. The particle’s Q/m is positively correlated with the airspeed. When the metal is triboelectrically charged with the insulator, the metal with a smaller work function leads to the insulator particle with a larger Q/m. As the moving distance of the particles increases beyond 230 mm, the particle charge ratio decreases. The particle charge-mass ratio is consistent with the trend of the charge-mass ratio deduced from the capacitance model.

Jun 3, 2023

By S. P. Sandoval

In 2002 the Freeport-McMoRan Technology Center undertook research to develop a lower-cost alternative to guar for cathode smoothing in copper electrowinning. The work was conducted at the Technology Center?s SXEW Test Facility located in Morenci, Arizona. Bench-scale copper electrowinning cells were designed and implemented to screen a number of potential polymers for cathode smoothing. These included modified polysaccharide polymers that were nonionic, cationic, and anionic in nature.

Jan 1, 2010

The value of US industrial mineral output last year was $20 billion, a 12% decline from 1981. A glance at the accompanying table and a review of the comments made by several contributors reveals how poorly many industrial minerals fared during 1982. Bromine and peat posted a 6% increase in production while recovered sulfur showed only a 3% gain over 1981. Pumice, salt, and dimension stone managed to stay more or less even with 1981 production. However, most industrial minerals posted losses for the year from 3% for vermiculite, sodium carbonate, and gypsum to 49% for ilmenite. Naturally, the depressed economy is to blame for decreased production and consumption. Low steel and auto production, lower housing starts, and many other factors impacted the industrial mineral industries. Hopefully the worst is over. Interest rates are down, energy costs are decreasing, the automobile and housing industries show signs of picking up. Perhaps the 1983 annual review will be less gloomy. Many thanks to these industrial minerals technical committee members for their contribution to this year's annual review: G. S. Austin, E. S. Montgomery, H. P. Ehrlinger III, D. B. Jorgensen, R. L. Parratt, J. F. Burst, W. Mallory, N. C. Trivedi, and N. K. Olson.

Jan 5, 1983

By Wu Aixiang, Zhou Qian, Zhou Zaibo, Liu Juanhong, Wang Hongjiang

To improve the pumping capacity and engineering efficiency of fresh thickened tailings slurry, a high charge density superplasticizer was developed to improve the rheological properties of tailings slurry. The effects of superplasticizer content, the concentration and fineness of tailings, the proportion and type of cementitious materials, temperature, and hydration time on the rheological properties of unclassified tailings slurry and backfill materials were studied. The variation characteristics of the slurry yield stress, plastic viscosity, and thixotropy with different factors were measured by a Brookfield R/S-SST plus rheometer. The experimental results of fresh thickened tailings illustrated that the higher the concentration of the slurry and the finer the tailings, the worse the rheological properties of the slurry. The results of cemented paste backfill materials indicated that the rheological parameters increased as binder content and time increased. The rheological parameters decreased as the temperature increased. The addition of a superplasticizer reduced the rheological parameters and improved the rheological behavior of the fresh thickened tailings and cemented paste backfill materials, which was beneficial to the slurry’s pipeline transportation. This paper can provide technical guidance for slurry transportation in the backfill system and provide a reference for designing the superplasticizer used in tailings.

Jan 5, 2022

By R. Bruce Sheibach

The Picher Mining District, located principally in north-eastern Oklahoma, was one of the world's largest lead-zinc mining areas during its 55 year life. The field covers an area of approximately 72 square miles (186 km.-); an estimated 1.6 x [103 yds3 of material (1.22 x 103m3)] worth in excess of one billion dollars, has been mined. Mining activities were typified by surface exploratory drilling identifying ore distribution and extension of underground workings to the lead and zinc deposits outlined. Exploration holes were either left unplugged or plugged at the surface with a section of a telephone pole. Low grade ore and waste rock were discarded in mined out portions of drifts. These waste piles containing pyrite and marquisette were left underground and oxidized during the many years of active mining. Upon cessation of mining activities in the mid-1960's, the drifts and shafts of the abandoned workings began to flood as the cone of depression filled in, leading to the dissolution of the oxidized sulfides and the formation of large volumes of acid mine water in the mined out openings. The resulting poor quality water, with high concentrations of cadmium, iron, lead and zinc, began discharging at the surface in 1979. Contamination of the underlying aquifer supplying local residents was first detected on a localized scale in 1980. The present surface water and ground water contamination have lead to the area being classified as one of the top ten hazardous waste sites in the U.S. by the EPA under the superfund program.

Jan 1, 1982

By X. X. Shao

Dewatering of ultra-fine clean coal slurry to a low moisture level of20 percent is difficult using the conventional techniques. A novel approach, which utilized mixing of fibrous waste material, such as paper, carpet and wood, with coal slurry prior to dewatering was developed. It was found that addition of about 10 Kg/t of carpet fibers or 5 Kg/t of raw paper pulp lowered the filter cake moisture from 22.5 to 18 percent. The compressive strength of the filter cake improved from 0 to 4.5 Kglcm2 and impact resistance from 0 to 4. The experimental data indicated that the handling character of the dewatered fine coal was improved significantly.

Jan 1, 1998

By Richard Newcomb, Michael Rieber, William A. Vogely

INTRODUCTION The solid fossil and nuclear fuels, but especially uranium, are given prominent, indeed leading, roles by energy experts in most long range estimates of world energy futures. Optimistic forecasts are inspired partly by the disproportionately large solid fuels resource base compared to present rates of consumption or to oil and gas resources, and partly by the vision of inexpensive high technology applications. Such a view overlooks the fact that while resource- use disparities and new technologies give allure to the promise of the solid fuels, they do not guarantee cheap solutions to the basic problems of solid fuel uses: viz., their relatively difficult conditions for efficient ignition and control, including the management of environmentally acceptable residuals disposal. Contrary to the varied versions of this optimistic hypothesis, this paper shows that a great many persistent economic and technical problems interfere with such a simple inference. These act as constraints which qualify or dispute much of the national energy policy based on existing modeling of solid fuel requirements and optimistic engineering evaluations. The assumptions and techniques of such exercises are sometimes at fault. As often as not, however, the distortions created in open market fuel com- petition due to misdirected national energy policies themselves are to blame for misdirected efforts. A number of interesting implications result. Among them are the distinct possibility that the low technology applications will dominate, so that more direct coal and less synfuel or nuclear use will occur; that, accordingly, exhaustion rates for uranium will be low, that the most extensive growth of solid fuel through 2000 will be in conventional pulverized coal cumbustors, and that the traded share of the world coal bum will be much larger than predicted. These trends will place much more pressure on oil and gas prices than forecast by most experts. On the way to these findings the paper demonstrates that solid fuel resource adequacy in situ, balanced against the projections of demands as capacity requirements, mean little as conventionally measured by years to exhaustion or potential supply schedules. Indeed, all stock concepts of demand requirements or of fuel re- sources must be tied to the paths of the unit costs and the deliverable prices of all substitute fuels and systems over time. This requires a dynamic analysis of supply and demand, integrated with geological and engineering constraints, to provide insights into the multiple modes of market and product substitution. Market forces rather than technical promise will determine the allocation of the solid fuels. Moreover, the equilibrium paths of individual fuel prices and market shares are not easily simulated by general or network models, and decision makers will continue to rely on the partial, local comparison of alternatives in their choices of fuel systems at any time. 'The economics of the solid fuels differs from that of other energy sources in important ways relating to their form in use, conversion efficiency, (dis)economies and externalities. Petroleum and gas are in a more convenient form for

Jan 1, 1985

By Pierre J. Goossens

Since Guild 1 and Snelgrove 2 attracted our attention to the relationships between certain endogenic ore deposits and plate boundaries, an abundant flow of papers appeared in the metallogenic literature concerned with this problem and its application to mineral exploration. Some of the papers only speculate with the formation of specific type of ore deposit 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 Other papers are more concerned with genetic and structural relationships between plate tectonics and mineralization 13, 14, 15, 16, 17, 18, 19, 20 They are philosophical, in that they are generalized and refer to no specific area. Yet it is true that a large part of the world mineral potential is concentrated at the convergence of oceanic and continental plates, for example, around the Pacific. Therefore, the interaction of two plates by either subduction, obduction or slippage likely has an important role for the genesis and/or the (structural) control of these "orogenic" ore deposits. If subduction is the driving mechanism for the generation of igneous rocks 21, 22 and endogenic ore deposits 18, volcanic activity and the nature of volcanic products certainly are the major geologic processes and events to be tested. Fonteilles 23 and Alsac 24 have already emphasized the important relationship between mineralization and the talc-alkaline affinity of the volcanics. The Andean orogen is one of the best areas for testing such genetic relationships. Rich and varied endogenic and volcanogenic ore deposits occur there and plate interaction is still active.

Jan 1, 1975

The Bureau of Mines, U.S. Department of Interior, is currently investigating strata interactions associated with the mining of multiple coalbeds. Strata interactions due to subsidence are a result of undermining. This study involves underground investigations at a mine where room and pillar panels are actively being developed through an area of the Sewickley Coalbed which was subsided by undermining of the Pittsburgh Coalbed. Research to date indicates that undermining had little effect on upper mine pillar stability, but had a more severe effect on the development and maintenance of entries. Roof-to-floor measurements recorded over four times more convergence in entries developed over gob as compared with entries developed over support pillars in the lower mine. Consequently, this has led to major roof falls in the active panels, resulting in considerable production delays and supplemental roof support costs.

Jan 1, 1985

By F. D. Ayhan

The aim of this study was to investigate desulfurization and de-ashing of a mixture of subbituminous coal and gangue minerals by the agglomeration method. For this purpose, experimental studies were conducted on a mixture containing subbituminous coal, pyrite, quartz and calcite. The effects of some parameters that markedly influence the effectiveness of selective oil agglomeration, such as solid concentration, pH, bridging liquid type and concentration, and depressant type and amount, were investigated. Agglomeration results showed that the usage of various depressants (Na2SiO3, FeCI3, corn starch, wheat starch) in the agglomeration medium has a positive effect on the reduction of ash and total sulfur content of agglomerates. It was found that an agglomerate product containing 3.03% total sulfur and 25.01% ash with a total sulfur reduction of 56.71% was obtained from a feed that contained 7% total sulfur and 43.58% ash when FeCI3 was used in the agglomeration medium. Key words: Desulfurization, De-ashing, Agglomeration, Coal, Gangue minerals

Jan 1, 2009

Adsorption of acrylamide based homo and copolymers on hematite was investigated as a function of phe nature of the polymer charge and functionality of the polymer. Effect of addition of sodium dodecylsulfonate and dodecylamine hydrochloride was also studied and was determined to result in an increase or decrease in the amount of polymer adsorbed depending on, the charge characteristics of the surfactant and the polymer, pH of the suspension, concentration of the various species and the order in which these species were added to the system. The surfactant adsorption under given conditions on the other hand, was found not to be affected by the presence of the polymer molecules. The data is analyzed to elucidate the mechanism of adsorption of polyacrylanide type polymers on hematite both with and without the surfactant species king present in the system.

Jan 1, 1982

By D. W. Hutchinson

One of the most important problems facing the coal industry today is the disposal of refuse from the coal preparation plants in a safe, economical, and efficient manner while complying with all legal requirements. The most commonly used refuse disposal method has been landfill/impoundment. In this method, the coarser refuse fractions are disposed of by layering and compaction into a landfill. The fine coal slurry refuse fraction is impounded in a dam constructed of a portion or all of the coarser refuse fractions. The failure of an impoundment at Buffalo Creek, Saunders, West Virginia and the sliding failure of a coarse refuse pile at Aberfan, Wales, England, resulted in an evaluation of refuse disposal methods by various regulatory agencies as well as coal producers. The result of this evaluation was the promulgation of Federal regulations dealing with the preparation, operation, and final abandonment of coal refuse disposal areas. As a consequence of these regulations the use of the landfill/impoundment method of disposal became in some cases economically unfeasible or technically impossible. At the time of the promulgation of the new Federal regulations, United States Steel Corporation was in the process of designing the Cumberland preparation plant. As a result of the new regulations

Jan 1, 1977

By E. Oraby, S. Garcia, A. Thurgood, D. Bertoldi, G. O’Malley

Mining and Process Solutions (MPS) most advanced process, GlyCatTM is the only process that can be easily adapted to existing cyanidation plants in the market today whose real advantages over cyanidation are when treating copper containing ores, concentrates or tailings. With such complex material, GlyCatTM requires 70-90% less cyanide addition to achieve the same precious metal extraction. However, GlyCatTM is not simply cyanidation with added glycine. It is a completely different process where the solution chemistry and conditions needed to effectively leach the precious metals are quite different. Downstream however, the process is largely unchanged as the recovery of the leached gold and silver uses existing known processes such as conventional activated carbon or zinc cementation (Merrill-Crowe process). Another advantage is lower SCN, OCN, WAD and no free cyanide in the effluent which can substantially reduce cyanide detoxification requirements and decrease the OHS and ESG risk of the operation. This paper outline some of these differences and presents testwork, piloting and process examples to highlight the advantageous of this new process over conventional cyanidation.

Feb 1, 2023

By Ronald J. Roman

A mathematical model was developed for the grinding and flotation section of Union Carbide's Bishop mill and this model was used to indicate how variations in grind, retention time, and calcite and fluorite content effects the mill capacity, tungsten units produced, and the grade and recovery of the scheelite concentrate. A model such as this is a starting point in determining the economic optimum running condition for a mining and milling operation and an example of this is given.

Jan 1, 1969

By Rodolfo V. de la Cruz

The stresses in the materials surrounding an underground opening are dependent upon the virgin stress field, the geometry of the opening and changes in boundary conditions as mining progresses. For most underground openings especially in coal mines, roof bolts are installed to help stabilize the opening. While most parameters in roof bolt design and installation have been thoroughly investigated, the effects of the initial stress field on the effectiveness of roof bolts have not been recognized. This paper summarizes the results of investigation of the effect of the initial stress field on the performance of mine roof bolts. Roof bolt installations are duplicated in the laboratory utilizing conventional roof bolt frame, commercial roof bolts and shells, mine torque wrench and encapsulated rock specimens for anchorage. A special and primary feature of the laboratory set-up is the addition of a loading system for generating stresses at the anchorage specimens. For this preliminary study, different levels of hydrostatic stress fields were induced at the anchorage specimen, instrumented roof bolts were installed in the usual manner, and the bolt load loss-with-time observed. Statistical analysis of data showed that the stress field at the anchorage horizon has a considerable influence on the performance of mine roof bolts, i.e. the higher the stress field, the higher the anchorage efficiency. From this observation, methods of improving the performance of mine roof bolts utilizing new shell designs and methods of installing them are suggested.

Jan 1, 1978