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By David Chastka, Isidro Rivera, Shawna Von Stockhausen, Idit Zarchi

The City of Santa Cruz Water Department is replacing the existing Newell Creek Dam inlet/outlet works at Loch Lomond Reservoir in the San Lorenzo Valley. The project will improve the City’s overall operational efficiency, improve system performance, and improve the safety and reliability of storage for the City’s drinking water supply. The project comprises new inlet works* (three new inlets that control and convey flows into and out of the reservoir, and an intake control building), an inlet/outlet tunnel with a 48-inch conduit to convey flows into and out of the reservoir, and a new outlet structure at the toe of the dam. The outlet structure includes a release point for energy dissipation of emergency drawdown flows, a connection to Newell Creek Pipeline, and beneficial releases into Newell Creek. The project also includes a new dam seepage collection and monitoring system and appurtenant structures such as a culvert bridge over the spillway plunge pool to improve access to the new outlet. Notable complex project components include in-water work to connect the new intake shaft pipes to the three new inlets. The project includes one major milestone with a work window regulated by environmental permits that could only be amended/ extended with approvals from those agencies. If not met, the milestone work would have caused significant delays (potentially up to one year) to the project.

Jun 13, 2021

By Andrzej Wala, Waclaw Dziurzynski, Janusz Tracz

Recent advancements in computer hardware have led to the development of new ventilation planning software for PC's. These programs now can be run more quickly and can display their outputs with graphical techniques. Only a few of the existing programs have the capability to display the output data graphically on plotters. Graphical presentation of ventilation simulation data is essential for quick and sure comparisons of alternative analyses. Recently a noticeable growth has occurred in the application of graphics for display and interpretation of the data that have been developed by simulation procedures. The process of mine ventilation network analyses used for planning and design can benefit from this development. The authors describe and present graphics-assisted software that has been developed to work with a mine ventilation simulation program. This software has some of the following features: - graphic editor on screen, - graphical display of output data on screen (EGA, VGA), - graphical display on plotter or printer, - scaling capability (desired part of the entire schematic can be displayed), and - such values as flow, pressure loss, gas concentration for branches, and pressure and elevation at junctions can be presented as labels.

Jan 1, 1991

By C. Basilio

Thermodynamic calculations based on a rigorous mass balance technique have been carried out for the chalcocite-potassium ethyl xanthate (KEX) system. The results of the calculations are used to: i) construct Eh-pH diagrams for KEX additions ranging from 0 to 10-4 M, ii) determine the amounts of cupric ions and copper xanthate formed at different Eh and pH values to make three-dimensional diagrams, and iii) determine the minimum KEX addition required to form CuX and CuX2.. This allows prediction of the optimum conditions for flotation and comparison of this with microflotation test data. In addition, voltammetry experiments have been conducted on chalcocite electrodes at pH 9.2 and pH 6.8 in order to gain information on the role of metastable species in flotation. On the basis of these experiments, possible reaction mechanisms are discussed and comparisons are made with what is expected on the basis of thermodynamics.

Jan 1, 1985

By M. Zhang, H. Ni, F. Zheng, M. Guo

"In the present work, we investigate the effects of roasting temperature and time on the transformation of the titanium (Ti)-bearing phase and magnesium aluminate spinel (MgAl2O4) phase in Ti-bearing electric arc furnace molten slag during the molten sodium hydroxide (NaOH) treatment process. With applied temperature of 700 °C for 60 min, and a mass ratio of Ti-bearing electric arc furnace slag to NaOH, or Rslag/NaOH, of 1:1.2, the conversion ratios of the Ti-bearing phase and the MgAl2O4 phase reached about 98.3 percent and 88.1 percent, respectively. Moreover, investigation of the reaction kinetics indicate that the conversion of these phases during the molten NaOH treatment process is a typical solid-liquid reaction, and it can be theoretically described by the unreacted shrinking core model. The conversion ratio of the Ti-bearing phase was found to be controlled by the chemical reaction step, with an apparent activation energy of 41.76 kJ/mol. The decomposition of the MgAl2O4 phase was found to be controlled by the surface chemical reaction in the early stage of 0 to 20 min from start of reaction, changing to diffusion control in the later stage of 20 to 60 min. The apparent activation energies of the process were determined as 55.88 and 22.72 kJ/mol, respectively.IntroductionChina has rich mineral resources of vanadium–titanium magnetite ore deposits, and the iron and steel industry in the country produces millions of tons of titanium (Ti)-bearing slag every year. The problem of how to dispose of the Ti-bearing slag has attracted much attention, and various approaches have been developed, including the acid process (Li et al., 2007; Zhang et al., 2011; Zhang and Nicol, 2010; Li et al., 2011), alkali fusion process (Han et al., 2012; Middlemas, Fang and Fan, 2013; Nayl, Awwad and Aly, 2009; Lasheen, 2008; Zhang, Qi and Zhang, 2009), carbonization and chlorination process (Liu et al., 2008; Tao et al., 2012; Fu et al., 2012; Liu, 2009), selective crystallization process (Lei and Xue, 2008; Li et al., 2011; Zhang et al., 2007a, 2007b). However, these processes have been beset by various functional, economical and ecological problems (Yu and Chen, 2010). With environmental protection regulations becoming increasingly rigorous, and demand growing for the comprehensive utilization of resources, the focus is on methods to treat Ti-bearing slag with high efficiency and mild reaction conditions (Nazari and Riahi, 2011; Wu et al., 2013)."

Jan 1, 2017

By Bijan Taheri, Behrouz Maghsodi, Monireh Heshami, Reza Kohan

A common problem recently encountered with the increase in the rate of input feed at Enrichment Plant 2 of the Sarcheshmeh Copper Complex is the loss of value to the tails, translating to lower recoveries. The feasibility of the direct transfer of part of the high-grade concentrate from rougher stages to an appropriate position along the circuit was studied, and two positions were proposed for direct transfer of the concentrate. One position was the feed flow into cleaner cells, and the other was the feed flow into the recleaner cell. The results indicated that transferring the concentrate from the first unit of the rougher stage to the feed flow into the cleaner cells was feasible, with no limitations, while the second position required the installation of a set of hydrocyclones. It was found that the transfer of concentrate to the proposed positions not only addressed the problem of limited cell capacity, resulting in debottlenecking of the circuit, but also improved metallurgical separation efficiency up to 1.4%.

By Richard L. Bullock

Drilling of small diameter blast holes in the conventional tunnel driving system or mining operation still consumes a significant part of the time and money required to extend an opening in rock. The use of pneumatic drills for most small hole applications has been the dominant tool used by miners and tunnel men alike throughout the world. But now, a, trend has been started that is showing major inroads into the traditional areas of pneumatics drilling for all types of rocks. Operators dealing in very soft materials, such as coal, salt or potash, traditionally had the option to use hydraulic power for their drilling tools. Twelve to fifteen years ago, drillers in medium hard, but nonabrasive rock extended their drill machine option by helping to develop a drill that still used air to power the hammers, but relied on hydraulic power for the rotational torque and feed thrust. (1) This was a significant step forward, particularly for those who drilled in rocks that were compatible to rotary-percussion bits. However, this application was in fact somewhat limited to the limestone and dolomite formation of mid-United States and the softer sediments in Europe. Now high performance rock drills have been developed, using all-hydraulics for both the hammer and rotation, that have many advantages over the conventional pneumatic systems. In two previous papers on this subject, (2)(3) this author reviewed in detail: 1) the characteristics of each of the manufacturer's products that were on the market; 2) The specific advantages of the all-hydraulic drilling systems; 3) Data from the applications of these drilling systems that was in use; 4) What was needed to further develop this drilling system and utilize its potential in the mining or tunnelling cycle. This paper will attempt to update previous papers, without reiterating many details of drill descriptions or

Jan 1, 1976

By NEHA PANDEY, V.K. REDDY KALLAM, SUNIL KUMAR TRIPATHY, ARIJIT BISWAS

This work discusses the sulfur dioxide (SO2) leaching of low-grade ferruginous manganese ores to selectively recover manganese (Mn) as manganese sulfate (MnSO4), followed by electrowinning of the purified MnSO4 to produce electrolytic manganese dioxide (EMD). The effects of the leaching process parameters on Mn recovery were studied, and the leaching duration and SO2 flow rate were found to have significant effects. Under the optimum conditions derived for grade 1 ore (with total Mn content of approximately 17.16 percent), the specific SO2 requirement (SSR) — that is, the SO2 flow rate per gram of Mn in the leach slurry — was calculated to be 0.014 L/min. At the SO2 flow rate calculated using SSR for grade 2 ore (with total Mn content of approximately 26.29 percent), a Mn recovery rate of 94 percent was realized. Electrowinning of the purified MnSO4 generated after leaching resulted in EMD with 88.01 percent purity and a γ structure.

Sep 1, 2022

By Clifford W. Schultz

Four native copper ores, two conglomerate and two amygdaloidal, were tested to determine their amenability to sorting. One of them, a conglomerate ore from the Kingston mine, showed a high sortability as evidenced by an 80 pct recovery of copper in the minus 6-, plus 1/2-inch size range. Using the Kingston as a case example, the cost of mining and concentrating was estimated for a standard case and five optional cases involving varying degrees of sorting. This analysis indi¬cates that the production cost per pound of copper can be reduced on the order of 1 to 1-1/2 cents per pound along with a significant decrease in capital investment.

Jan 1, 1975

A Directory of Computer Programs Applicable to US Mining Practices and Problems. A. L. Sanford, T. L. Myers, and J. F. Stiehr. USBM OFR 131-78, Nov. 1977. A Master Environmental Control and Mine System Design Simulator for Underground Coal Mining. Tape MDS-5. Pennsylvania State University. USBM CT 1.77, Dec. 1975. Contains computer programs on a dynamic general purpose computer simulation model for underground coal mining. A Method for Computing Stabilization Pressures for Excavations in Incompetent Rock. J. D. Dixon and M. A. Mahtab. USBM RI 8128, 1976. Describes technique for determining the confining pressures that must be provided for stabilizing underground openings in incompetent rock. Accident Cost Indicator Model to Estimate Costs to Industry and Society From Work-Related Injuries and Deaths in Underground Coal Mining. Vol. I.III. D. G. DiCanio, A. H. Nakata, D. Colvert, and E. G. LaVeque. OFR 39(1)(3)-77, Dec. 1976. Describes a computer-based model for estimating the tangible costs of injuries and deaths from work-related accidents In underground coal mines. An Interactive Computer System for Evaluating Coal Mine Illumination. R. Goldstein. USBM OFR 110-80, March 1980. Computer system for calculating the illumination on coal mine surfaces due to machine-mounted lights. Analytical Modeling of Mine Roof Behavior Using Statistical Material Properties. R. T. Langland and F. J. Tokarz. USBM UCRL-51876, Aug. 1975. Analytical study of coal mine roof behavior using a computer model of a room-and-pillar mining method. Application of a Total System Surface Mine Simulator to Coal Stripping. Vol. I-VII. Pennsylvania State University. USBM OFR 33(1)(7)-78, Aug. 1978. Describes model development, input and output documentation, three case studies of an open-pit materials handling simulator, and development of two equipment selection models and a cost model. Characterization of the Structural Behavior of Rock Masses. Vol. I-II. L. R. Herrmann and M. A. Taylor. USBM OFR 67(1X2)-75, Sept. 1974. Computer subroutines for characterization of rock behavior, Including variability of properties within the rock mass, planes of weakness orthotropy, strength criteria, and post-failure behavior. Coal Mine Electrical System Evaluation. Vol. I-VII, L. A. Morley, et al. USBM OFF! 61(1)(7)-78, 1977. A concept to improve underground coal mine electrical system safety and availability. This proposed technique is based upon the ability to predict incipient failures in the mine power system. Prediction is made possible by a new method which uses a minicomputer to implement pattern recognition algorithms. Computer Modeling of Fluid Flow During Production and Environmental Restoration Phases of In Situ Uranium Leaching. R. D. Schmidt. USBM RI 8479, 1980. Describes development and application of a computer model for simulating the hydrological activity associated with in situ leaching. Interpretation of Rock Mechanics Data, Vol. II (A Guide to Using UTAH2). W. G. Pariseau. USBM OFR 47(2)-80, June 1978. Brief description of a two-dimensional elastic-plastic finite element program intended for mine stability analysis. Iterative Approximation Techniques for Microseismic Source Location. G. H. Dechman and Meng-Cherng Sun. USBM RI 8254, 1977. Iterative approximation method for microseismic source location developed to adapt microseismic techniques for rock structure analysis to investigations of surface problems such as slope failure in an open-pit mine. Limits and Cost Sensitivity of Alternative Parting Handling Methods. Vol. I-II. T. E. Finch, D. R. Haley, and C. J. Speaks, Jr. USBM OFF! 117(1)(2)-77, March 1977. Programs to examine alternative methods of handling the parting between two coal seams in a surface mining operation. Alternative methods consist of equipment implementation in either a stowing or haulback technique. Methane-Water Flow in Coalbeds. H. S. Price. USBM CT 1-79, April 1972. This computer program calculates transient, two-dimensional, gas¬water flow in a porous medium. Plastic Canopy-A Computer Program for the Structural Analysis of Protective Canopies. K. D. Winters, G. A. Gavan, and J. C. Ault. USBM IC 8795, 1979. Presents a FORTRAN IV program for the structural analysis of protective canopies used In underground mines and rollover protective structures used in surface mines. The Three-Dimensional Structural Analysis of Double-Entry and Single-Entry Coal Mines. Vol. I-III. Agbabia Associates. USBM OFF 16(1)(3)-80, Oct. 1978. Describes the computer program designed to perform a three-dimensional finite element analysis of an instrumented section of double- and single-entry coal mines. Underground Mine Evacuation Plans Analyzed by Computers. D. Tesarik, D. Nicholson, and A. B. Boghani. MSHA, Vol. 4, No. 5, Oct. 1979. USBM has developed a computer program to evaluate and construct mine evacuation procedures and plans.

Jan 11, 1981

By B. Zane Egan

The Calsinter process for recovery from fly ash involves sintering the fly ash with calcium sulfate and calcium carbonate at 1200°C, followed by a dilute sulfuric acid leach step. Flue gas desulfurization sludge containing calcium sulfite, calcium sulfate, and unreacted calcium carbonate may be substituted for the calcium sulfate and calcium carbonate. Conversion of aluminum in fly ash by the sintering process to an acid-leachable species was measured as a function of sintering time and temperature in the range of 800°-1200°C The sinter-leach steps were investigated using thermogravimetric analysis, x-ray diffraction, scanning electron microscopy, and elemental analysis. SEM photographs indicated that the glassy spheroids in the original fly ash were converted to a crystalline structure by the sintering reaction.

Jan 1, 1980

By Aarne Visnapuu

Unmodified pneumatic rock drills may have noise levels of 115 to 130 dB at the operator's position. Experimental modifications have been made to a standard drill to suppress the noise from the three main sources: the air exhaust noise, the noise radiated from the drill, and the resonance noise of the steel drill rods. A prototype model developed at the Bureau of Mines, Rolla Metallurgy Research Center, operates at a noise level below 100 dB. A close-fitting case and muffler unit, consisting of a metallic skeleton filled with viscoelastic absorber and having a durable cover, provided both muffling and noise absorption. Damping alloys were used at strategic points in the drill. Drill steel resonance noise was reduced by a constrained-layer treatment on the outside of the drill rod. The singular and combined effects of the treatments are presented in detail.

Jan 1, 1973

By Scott G. Britton

Many times during the construction of a project, whether large or small, the engineer will become involved with management of the work and workforce. In some cases, mine management will turn over the direction and responsibility of doing the work to the engineer. Because of this, it is important to know some of the basic principles of human resource applications- among other management concerns. This chapter, therefore, looks at the fundamental principles of human resource management. Three broad discussions are presented to the reader. These are: (1) organization, communications, and responsibilities of management; (2) analysis of worker motivation; and (3) supervisory leadership. Each topic encompasses the current thinking for coal mining and mining management. Much of the information in this chapter comes from Practical Coal Mine Management, by this author and published by John Wiley & Sons, Inc., which discusses in depth many of the ideas presented here. Interested persons are directed to this text for more information on management skills.

Jan 1, 1983

By L. F. McHugh

Molybdenum conversion operations discussed in this paper encompass all major operations commercially used to upgrade molybdenite concentrates to various refined products. More emphasis is placed on discussion of key pyrometallurgical unit operations. These operations conducted at Metec include roasting, sublimation, and hydrogen reduction

Jan 1, 1986

By M. Misra, J. Nanor

The removal and stability of arsenic over a wide pH range (3.0-10.0) from synthetic solutions and industrial waste effluents (including mining waste tailing slurry) can be accomplished with addition of impure lanthanum chloride alone or in conjunction with ferric sulfate. The long term stability of these correspond­ing precipitated compounds is critical from the disposal stand­point. In this paper test results of this new process for arsenic removal and stabilization from the above mentioned systems are presented. Also, precipitated arsenic compounds (lanthanum arsenate, lanthanum-ferric arsenate, ferric-lanthanum arsenate and ferric arsenate) from synthetic solutions have been charac­terized. The characterization technique used was XRD. XRD patterns which shows that the lanthanum arsenate and lan­thanum-ferric arsenate formed in acidic and alkaline pH at room temperature are crystalline. On the contrary, ferric arsenate and ferric-lanthanum arsenate compounds formed under the same conditions as lanthanum arsenate were amorphous.

Jan 1, 1998

By S. Vukcevic, R. Winby, P. C. Miller

There is considerable interest in the bioleaching of chalcopyrite concentrate for the production of copper. The residue of bioleached chalcopyrite often contains gold that needs to be recovered. Despite the high efficiency of copper bioleaching, the residue may contain appreciable quantities of copper, and the difficulties of cyanidation of gold from copper bearing materials are well recognised. This paper reports the results of using different methods to recover the gold values from bioleached chalcopyrite concentrate. In particular, the behaviour of cyanide and cyanide in the presence of ammonium ions as gold lixiviants were studied. The ammonia was employed to reduce the impact of the copper on cyanide consumption. Thiosulphate as a gold lixiviant was also employed with the aim of achieveing rapid leaching rates and to reduce the impact of residual sulphur species on lixiviant consumption. Bromine solution was used to research acidic gold leaching. The paper describes the advantages and disadvantages of using different reagents with respect to reagent consumption, selectivity and kinetic efficiency.

Jan 1, 1997

By Ron Jackson

The report gives a general method for the geological evaluation of a gold deposit. Recognizable parameters associated with gold mineralization are used to develop a model of an orebody. The California Mother Lode is used as an example.

Jan 1, 1987

By Susan G. Bilhorn

A number of studies have been conducted in active and inactive mine environments using continuous monitoring and data acquisition systems to detect various parameters. In addition to the information obtained for research purposes, these monitoring systems can provide a means to remotely collect required information (such as radon daughter concentrations and air velocity) and control various conditions (such as fan operation and air door position) in numerous working sections of an active mine. Selection of detector locations and placement, which are critical to obtain the information and control desired while not inhibiting mine operations and influencing the detector readings, are covered in this paper.

Jan 1, 1984

By William F. Stowasser

The organization and operations of the information gathering system, and examples of the products prepared for the commodity phosphate rock by the Division of Nonmetallic Minerals, U.S. Bureau of Mines, are used to describe the Bureau's commodity program. Selected examples from publications about phosphate rock are used to illustrate the program. The Commodity Divisions reporting to the Office of the Assistant Director-¬Metals, Minerals and Materials, have the responsibility in the Bureau of Mines to maintain commodity records, understand the present supply and demand status of the commodity, and forecast future supply, demand, and problems. Within the Divisions, commodity specialists have the broad charter of acquiring as much information about a commodity as is necessary to characterize its history, current status, and future. This information and understanding are the base for the development of mineral policies. To accomplish these objectives, the commodity specialists acquire data and information about each commodity and produce a number of standard publications each year. In addition, as circumstances dictate, each specialist will prepare or participate in the preparation of special documents for specific purposes or problems associated with his commodity. In the preparation of reports and publi¬cations, he may communicate with industrial organizations and other Government agencies.

Jan 1, 1975

By C. Y. Chen

In order to put an end to the uneven environmental standards and enforcement established by various coal mining States in the United States, the Congress passed and the President signed the Surface Mining Control and Reclamation Act (Public Law 95-87 or the Act) on August 3, 1977. Within one year after passage, the Secretary of the Interior was directed to promulgate permanent program regulations implementing Title V provisions of the Act. These regulations were to form the basis for State regulatory programs under the Act and to allow States to assume primary regulatory responsibility. In order to implement the underground mining provision of the Act, the Secretary is directed in section 516(a) of the Act to promulgate rules, but ones which take into consideration the distinct differences between surface coal mining and underground coal mining. The regulations developed by the Secretary and promulgated on March 13, 1979, with respect to subsidence control, included (1) a subsidence control plan as part of the permitting process, (2) substantive provisions establishing performance standards for subsidence control, and (3) provisions providing for the prohibition of mining under perennial streams, impoundments larger than 20 acre feet, and certain public facilities and urban areas.

Jan 1, 1985

By Jr. Raleigh

In a cooperative agreement between the U.S. Bureau of Mines and the U.S. Department of Energy, laboratory column-flotation tests were conducted to evaluate fluorosurfactants as selective fine coal flotation collectors. A Middle Kittaning seam coal responded to flotation with both anionic and nonionic fluorosurfactants. These fluorosurfactants were no more selective than MIBC alone. However, for increasing coal yields, nonionic fluorosurfactant systems did not increase total sulfur and ash contents as sharply as MIBC systems. Flotation selectivity also improved slightly when a combined anionic fluorosurfactant-MIBC system was used in acidic pulps (pH < 3.6). While the fluorosurfactants examined will not likely have direct application in current coal flotation practice, other fluorosurfactant systems could eventually prove beneficial for floating fine coals.

Jan 1, 1990