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By Ernest Selig, John Dunnicliff, Delon Hampton

This paper provides a summary of a two-day conference held in New Orleans in March 1980, entitled "Tunnel Instrumentation: Benefits and Implementation." The conference addressed two major questions: First, what are the benefits of using instrumentation during tunnel construction? Second, what contractual relations should be established for conducting instrumentation programs during tunnel construction? Each session consisted of brief formal presentations and extensive panel discussions with participation from attendees. Attendees included owners, designers, contractors, and instrumentation specialists. This paper presents a consensus of views expressed during the conference.

Jan 1, 1981

By K. Hebbar, R. G. Reddy

The viscosities of various FeO-SiO2 slags were calculated using a previously developed structural-based model. Using hole theory and the atomic pair model, an expression was derived to relate the viscosity to temperature and the fraction of the bridging oxygen in silicate melts. The deduced equation was successfully applied to predict the viscosities of FeO-SiO2 slags in the composition range of 0.1 < XSi02 < 0.423 for several temperatures. The calculated data agree well with the experimental viscosity data.

Jan 1, 2002

By L. D. Gehi, A. W. Khair, M. Ahmad

This paper presents an analysis of the effect of the dynamics of bit wear on dust generation. Two surveys have been conducted in order to assess the mechanism and type of bit wear and to evaluate the impact of bit wear on the productivity of the continuous miners. Used bits were collected from the underground coal mines and these used bits were utilized in laboratory coal cutting. The effect of bit wear on dust generation has been quantified and its impacted on dust generation and ventilation system has been exemplified.

Jan 1, 1993

By Karen L. Menna

At Digital Equipment Corporation, increasing demands on executive secretaries to share, track, and retrieve information prompted development of ALL-IN-1 System for Executive Services. Executive secretaries asked engineers to combine word processing and electronic mail with utilities for managing time; logging and tracking telephone calls, letters, and inquires; creating presentations; compiling directories; and archiving. The system, two years in development, now automates the president&apos;s and senior vice presidents? offices at Digital. It allows secretaries to interrupt any task with two keystrokes, and return later to the original task. The system has speeded customer response, enabled online information sharing, and increased professionalism and customer satisfaction.

Jan 1, 1989

By R. L. Pozzo, A. S. Malicsi, I. Iwasaki

The electrochemical nature of mineral-grinding media interaction in the wet grinding of one and two sulfide mineral ores was investigated with regard to the flotation behaviors of the minerals. Two iron sulfides (pyrite and pyrrhorite) and mild steel were used to represent the sulfide minerals and the grinding media, respectively. Galvanic currents in two- and three-electrode combinations under abrasive and non abrasive conditions were correlated with the floatabilities of these minerals under corresponding conditions.

Jan 1, 1991

Magnetic separators are commonly used as an effective and low-cost method to concentrate paramagnetic or ferromagnetic minerals. These versatile separators are often used in multistage circuit configurations to further improve concentrate recovery and/or grade. Although these circuits are generally very efficient, field studies suggest that the layout of multistage circuits can be less than ideal for many industrial operations. To illustrate this shortcoming, a theoretical analysis has been conducted to compare different circuit configurations for magnetic separators. The resulting knowledge base has been used to establish generic engineering guidelines for the layout of multistage circuits. The potential improvements in separation efficiency that may be realized through the application of these guidelines have been demonstrated using a simple case study.

Jan 1, 2004

By D. John Curtis, Gordon S. Crighton, John C. Hester

The six main drives needed to build 55 miles of 4.8 and 7.7 metre i.d. tunnels in 33 months called for careful co-ordination of the design of tunnel boring machines and linings. The implications of these requirements are discussed, with particular reference to the selection of tunnel liners. The solutions adopted are detailed and details are given of the specifications and procedures adopted. The design methods employed for liners are outlined. The construction methods are described and current performance figures given.

Jan 1, 1991

By O. A. Bascur

Based on current sedimentation theory an on-line thickener model was developed and coupled with an extended Kalman Filter to obtain additional information such as the compression zone level and concentration, a corrected underflow concentration, the inventory, and some rheological information. The on-line model was installed and tested for robustness for periods up to three days in an industrial environment giving good results. Emphasis was given to signal processing and selecting the appropriate input variables for filtering. The analysis of the thickener from a phenomenlogical point of view provides for better operation, establishes the limiting operating conditions, and assists in the design of control strategies.

Jan 1, 1986

By Walter J. Johnson, Robert L. Chufo

A unique non-contracting coal thickness measurement technique has been developed to measure both the dielectric constant and thickness of a coal seam as part of a sensor array supporting an autonomous coal mining machine. The sensor measures the reflection of an electromagnetic signal from the coal/shale interface. Underground measurements of coal 6- in thick with a dielectric constant of 4 have been confirmed. Measurements were also made of a 31-in thick coal pillar for application of the sensor to highwall mining. The electromagnetic measurement technique, the data reduction process and field test experience will be presented.

Jan 1, 1992

By K. J. Stanaway

Environmental pressures on waste disposal are forcing pigment producers to use feedstocks with higher Ti02 content and lower levels of trace elements. Despite this, 50% of the world&apos;s Ti02 comes from ilmenite concentrates with only 37% to 54% Ti02. An industry growth rate of 25% in the next 10 years, combined with trends to diminishing resources and lower mining grades for rutile (95% P02) and leucoxenized ilmenite (55% to 90% P02), means that unless new discoveries are made soon, the industry will become even more reliant on ilmenite.

Jan 1, 1995

By Jorge Martinez

The Muck Valley Hydroelectric Project in Northeastern California required construction of a 3.65 meter tunnel through 6,623 meters of mixed volcanic flow deposits within a critical time frame. As Engineer and Construction Manager for the Project, Morrison-Knudsen Engineers invited bids for both Drill and Blast as well as Tunnel Boring Machine methods, selecting a contractor proposing a TBM designed and built specifically for this project which could excavate a wide variety of materials and maintain acceptable progress rates to complete the work within schedule. Tunnel lining as required included shotcrete with metal fibers and full circle concrete.

Jan 1, 1989

By G. T. Adel, J. D. Miller, C. L. Lin

In view of the success of recent laboratory studies using X-ray computed tomography (CT) to determine coal washability and with the availability of high-speed CT systems, it now seems possible to design an on-stream washability system for the control of coarse coal-cleaning circuits. Design features for such a system are examined and possible control strategies are discussed for different applications.

Jan 1, 1995

By P. C. Rath, K. Srinivasa Rao, T. Subbaiah

A process for the recovery of nickel from ammoniacal leach liquor through an integrated solvent extraction-electrowinning (SX-EW) flowsheet was tested on a pilot-plant scale. The objectives of the test run were to assess the reproducibility of laboratory-scale data in a large-scale continuous operation and to study the build up of impurities in the system. The pilot-plant test was conducted under operating conditions that were established from the laboratory-scale experiments. Efficiencies of nickel extraction, nickel stripping and ammonia scrubbing were comparable to the laboratory-scale values, whereas the current efficiency during nickel electrolysis was observed to be less than the laboratory-scale values. The electrodeposited nickel contained some cobalt and iron impurities.

Jan 1, 1998

By David G. Chedgy, Edward A. Zawadzki, Robert D. Stoessner

Extensive research and testing in commercial facilities has clearly demonstrated that heavy medium cyclones are the most effective process for cleaning a 0.6 x 0.15mm (28 x 100 Mesh) coal at low separating gravities, less than 1.35. This paper describes testing performed to deter- mine system characteristics at these lower gravities and the type of circuitry required to maximize performance. The results of these studies include both pilot and commercial scale tests of cleaning 0.6 x 015mm (28 x100M) coal.

Jan 1, 1988

By Daniel Hodouin, Claude Bazin, Sami Makni

Computer systems, installed in mineral processing, are designed to accumulate massive amounts of real-time data. Frequently these data are only partially processed because of the lack of adequate methods and the limited accuracy of mineral processing sensors. Methods are proposed to estimate missing data and reconciliate sensor data on a real-time basis. They are based on dynamic extension of steady-state techniques such as the node imbalance minimization or the least-squares mass balance adjustment techniques. The methods are illustrated for simulated and actual flotation data. Their data upgrading ability could be used to improve process monitoring, control and optimization.

Jan 1, 1993

By J. Brent Hiskey, Srini Raghavan

The physical chemistry of dissolution of silicate and complex oxide ores in aqueous lixiviants has been reviewed. Particular attention has been paid to the analysis of dissolution mechanisms and kinetic models and to the elucidation of the role of the porous nature of the materials on dissolution behavior. Importance of the physico-chemical characteristics of the leach residues on leaching efficiency has been discussed.

Jan 1, 1989

By R. L. Grayson

As a followup to a USBM-sponsored research project, the authors utilized the knowledge-base structure and system concepts from a Sun Sparcstation-based worker-scheduling system of the mine-management support system to develop a PC-based application. The new software adopts the nested-window concept to facilitate data collection and modification on personnel, including their availability and work priorities during a shift. The system can optimally allocate manpower on a work shift and can delineate supervisory training responsibilities. The various components of the software, including enhancements made to the original system, are described in detail.

Jan 1, 1997

By Chinmoy Sarkar

Mining organizations have been trying to employ best practices at exploration, exploitation and processing level to increase productivity in the supply chain. Traditional techniques of cost control can no longer meet the ambitious target of mine managers. An integrated perspective of Mining Value Chain with enterprise-wide application of information technology (IT) ensures the ability of every mining processes to improve energy, land, capital and labour resource performance while continuing to cut costs and achieve profitability. IT offers enormous potential in mining industry at shaping entirely new opportunities to create value. This paper characterizes important entities of Mining Value Chain and attempts to provide a vision on how IT can transform the mindsets of industry managers addressing the needs of the customers.

Jan 1, 2002

By A. G. Journel

Few Earth Scientists realize fully the assumptions they are making, willing or not, when pooling into a same histogram data coming from different locations and considering such histogram as an estimate of a probabilistic distribution. First they need the hypothesis of stationarity in space; second the presence of spatial auto-correlations implies that data be unequally weighted according to their relative locations and the degree of spatial continuity of the underlying phenomenon. The novel technique of indicator kriging allows construction of local or global histogram which can be considered as unbiased estimators of precisely defined probabilistic distributions, full account being given to the underlying continuity. Such estimates of local distributions can be used in mine planning for estimation of local recoverable reserves.

Jan 1, 1982

By Ralph D. Daley, Kevin E. Redinger

The production of coal/water fuel (CWF), a highly loaded mixture of finely ground coal, water, and chemical additives, presents a unique opportunity for significant ash and sulfur reduction through physical coal cleaning. Froth flotation can be integrated with the staged, wet, fine grinding inherent in the CWF production process. A laboratory scale research program was conducted to demonstrate the feasibility of a flexible, integrated coal cleaning/CWF process flowsheet. Performance of the conceptual flowsheet was examined for two coals of CWF commercial interest, Upper Freeport and Pittsburgh seam coals, from central and southwestern Pennsylvania, respectively. Several multi-stage coal flotation and reverse flotation circuits were evaluated. CWF was produced from the cleaned coal in each case at similar solids loadings and viscosities as observed for the raw coal. However, the ash loading and SO2 emission potential for each CWF had been significantly reduced.

Jan 1, 1988