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By CHONG WEI, TATYANA KATSAGA, DEREK APEL

This study provides an effective determination process of the interface microstructural parameters in the numerical modeling of the mechanical interaction between two different geomaterials involved with frictional-bonded interfaces, such as the interaction between backfill columns and the surrounding rocks, or the soil-structure interaction, by using the coupled finite-difference and discrete-element (FD-DE) method. The test results validated the feasibility and rationality of the coupled FD-DE method for modeling the combined specimens with frictional-bonded interfaces or joints. Furthermore, this study provides valuable numerical modeling experience for investigating the shear behavior at the interface between cemented backfill columns and surrounding walls by using the coupled FD-DE method.

By J. A. Bleeck

A discourse on the relationship between industrial minerals and paper production, concentrating on high grade, ultra fine ground calcium carbonate (mean particle size less than 2 microns) and precipitated calcium carbonate. The scope of the paper encompasses four basic areas relevant to the topic: 1. A tutorial overview of the papermaking process with an examination of various industrial mineral components in that process; 2. A discussion of basic technological topics pertinent to the utilization of carbonate in paper with emphasis on the relative aspect. Of natural ground calcium carbonate (GCC) and synthetic precipitated calcium carbonate (PCC); 3. An overview of paper and carbonate market, in both the United State, and Europe with emphasis on (a) current status and future growth trend. Of such market., and (b) discussion of the major influences on growth and development of such market.; and 4. Identification and discussion regarding the principal producers in calcium carbonate markets serving the paper indu.try in Europe and North America.

Jan 1, 1993

By John Murray, Ryan Smith, Daniel Ebin, Robert Gould, Thomas Hennings

The Atlanta Plane Train Tunnel West Extension was excavated at Hartsfield-Jackson Atlanta International Airport using Sequential Excavation Methods (SEM). At its shallowest point, tunnel cover to bottom of Domestic Terminal footings was limited to 6 feet in soft ground. To mitigate risk of excessive building movement due to tunneling-related activities, the columns near the alignment were directly underpinned. Underpinning was accomplished using a combination of grouted mini-piles, installed under low headroom conditions, that supported steel framing spanning over the tunnel excavations. This paper focuses on design and construction of the underpinning system used to mitigate risk from tunneling.

Jun 13, 2023

By J. J. Antony

The Cactus Gold Mine is a joint venture comprised of Middle Buttes Partners Ltd. (CoCa Mines, Inc.--operator, T. Congdon and W. Carey) and Compass Mining, Inc. The project includes 2.4 sq. miles of contiguous mining claims and leases in the Mojave Mining District, Kern County, California, approximately B5 miles northeast of Los Angeles. The property is readily accessible year round by all-weather roads and is within 6 miles of the main line of the Southern Pacific Railway.

Jan 1, 1988

By W. de Bruijn

Differential reduction and expansion or shrinkage of hematite under the influence of intimately associated foreign oxides may be a source of stress formation and sinter degradation during blast furnace reduction. To study specific effects, synthetically pre-pared hematite powder evenly doped with 1% by weight of several elements present as oxides, was pressed into tablets and sintered at high temperature prior to reduction. Continuous thermo-gravimetric and dilatometric analyses were per-formed on the sintered tablets as these were being subjected to reduction under simulated blast furnace time/temperature/gas composition conditions up to 1183 K. These findings were coupled with observations on the microstructure of tablets removed from various stages of the reduction process.

Jan 1, 1988

By P. N. Bradbury

The coal companies of today have to make all of their in-the-field managers MAINTENANCE PRODUCTION MANAGERS. By using a computer application to monitor all aspects of the daily production as well as the maintenance, a company can immediately effect a cost reduction by studying the down-time and delay trends on an everyday basis. This paper will outline how a company can use a program to not only put a stop to the increasing supply and maintenance costs but start trimming each of these cost centers while actually increasing the efficiency and productivity of the current work force.

Jan 1, 1991

By J. E. Friant

The Mini-Disc TM cutter drill bit is a radical design departure from the traditional tri-cone rock drill bit. Miniature disc type cutting tools as small as 3.25 inches (82.5 mm) diameter are fitted to a bit body to cut individual concentric kerfs. The action is the same as that commonly used on large tunnel boring machines but miniaturized. The high performance rate and efficiency of a disc cutter are the result of producing a large proportion rock chips rather than sand or powder. The Mini-Disc TM drill bit, referred to as the "Disc Bit" has other unique features as well. It can be re-greased between runs. It can be rebuilt in the field in about 15 minutes, cutters can be replaced and the Disc-Bit appears to require less down hole hydraulic power than conventional bits. Thoroughly tested in the laboratory, the bit has recently been undergoing field trials in well drilling, blast hole drilling and shaft drilling. As any engineer knows, the laboratory cannot shake out all the problems but it eliminates the more glaring weaknesses. Performance results have been exhilarating, and a few mechanical problems were discovered and largely overcome. This paper is a progress report.

Jan 1, 1999

By D. Leppert

Clinoptilolite zeolite may offer attractive, cost-effective alternatives for remedial cleanup of old minesites, smelters and other sites with heavy metal contamination. Previous research demonstrates the relatively strong affinity of clinoptilolite for numerous metals and clinoptilolite displays a particularly strong affinity for lead (Loizidou and Townsend, 1987), one of the most toxic and problematic heavy metals. Since clinoptilolite can also selectively absorb some radionuclides and organic compounds, it may offer practical solutions to a wide variety of environmental problems.

Jan 1, 1989

By E. Ilgar

Biodegradation of spodumene by Asnergillus niger has been investigated. This organism oxidizes sucrose to citric and oxalic acids (in approximately 50-sot proportions) which degrade the spodumene mineral. The kinetic effects of leach variables on the dissolution of lithium were determined. The maximum theoretically attainable rate of lithium extraction was calculated for the effect of pulp density, to be V : 3.01 x 10 kg m sand the corresponding constant value, K = 12.47% pulp density. The apparent activation energy of lithium extraction vas found to be ^E = 20.3 kJ and frequency factor A = 5.66 x 10 s for S-spodumene leaching by synthetic -3 citric and oxalic acids (each in 0.05 kmol m-3 concentrations).

Jan 1, 1989

By V. R. Bovino

In the early 80's, the cover of a major weekly magazine proclaimed the "Death of Mining." A few years ago, mining conventions, similar to this, around the country sported the theme, "The Survival of Mining." Today, the SME announces that "Mining is Alive." Being part of an industry that is simply alive is not very exciting. We can do better! Our challenge must be to flourish, blossom, maximize our potential and expand our horizons. The pace of rejuvenating this industry is still woefully inadequate. The new generation of mining industry leaders recognizes the urgent need for bold operational changes?changes in the way we deal with our employees? changes in the way we achieve productivity? and changes in the way we reward our employees for productivity.

Jan 1, 1991

By S. S. Mauney

Natural and synthetic colors are used in almost every facet of our daily lives as a means of communication and expression. Natural ochres, umbers, hematites, and magnetites were once used in their crude or semi-processed state for their pigment value in construction products and low-end coatings applications, while yielding, in recent years, to synthetically produced iron oxides for more sophisticated products. Today, through innovative mining, processing, and marketing techniques, natural iron oxide pigments are once again gaining strong inroads into products and markets requiring precise chemical and physical characteristics. With our focus on environmental consciousness and resource conservation, value added natural iron oxides provide an economical and responsible alternative to our color needs.

Jan 1, 1993

By Frank W. Schmechel

The subsidence monitoring program at the Old Ben No. 24 Mine was planned in 1976 as part of the on- going demonstration of longwall mining. The construction and installation of the network of surface subsidence monuments was started in Play of 1976 and completed four weeks later after which an initial reference survey was made of all surface monuments. Mining of the first longwall panel started in September of 1976 and was completed in May of 1977. Mining of the second panel started in August of 1977 and is continuing at this time. The Automatic Data Acquisition System (ADAS), which is the subject of this paper, was installed over the second panel on March 29, 1978 near the panel center (Figure 1) and approximately 104 meters (370 feet) in front of the face position at that time. Mine No. 24 is located approximately 5 kilometers (3 miles) Northwest of Benton, Franklin County, Illinois. Coal is being mined from the Illinois (Herrin) No. 6 seam which is at a depth of about 189 meters (620 feet) at the site. The Herrin No. 6 is up to 2.7 meters (9 feet) thick in the mine but a constant thickness of 2.1 meters (7 feet) is being mined by the demonstration longwall with both roof and floor coal being left for stability. Although the seam is flat laying at the mine, it dips north- ward regionally. Topographically, the surface over the demonstration panels is essentially flat and low laying with several areas of standing water. The Rend Lake Dam (United States Army Corps of Engineers) is about 305 meters (1000 feet) north of the demonstration site.

Jan 1, 1979

By Walter M. Chapman

The National Lead Company operates its MacI tyre Development at Tahawus, New York for the production of ilmenite and. magnetite. The heavy ore of titanium and iron is mined from the open pit mine at an average rate of 7,000 tons per day, and the development waste is removed at an average rate of 10,000 tons per day. The mine working benches are spaced, at 35-foot vertical intervals, and 6 ½ inch blast holes are drilled 39-feet deep with 18-foot burden and spacing by down-the-hole drills. Waste is loaded with a 6 yeard shovel and ore with 2 ½ yard shovels into 22-ton rear dump trucks. A good account of the history of MacIntyre drilling and. blasting was presented to this assembly two years ago, by F. R. Jones. (1) Most of the blasting since the start of the mine in 1941 was done with 90% gelatin dynamite until 1955, when relatively insensitive canned blasting agents were adopted.. In 1956, 9-inch blast holes drilled with down-the-hole drills. In 1956, also, the first experimental trials of prilled ammonium nitrate fertilizer and fuel oil (hereafter called fertilizer) was made following the lead of Cleveland-Cliffs operations in the Hibbing district. Since that trial did not, as some local skeptics predicted, make grass grown on the bluff, but resulted in a well-broken shot, further tests were conducted in dry holes. I Observations of those tests indicated that the fertilizer did its share of the work. If anything, it produced better fragmentation than the normal load di in neighboring wet holes.

Jan 1, 1958

By H. Janas

In a gas/coal outburst the gas plays an active, driving part. The proneness of coal to outbursts can be determined by means of its gas emission properties, since coal that is liable to outbursts differs from coal with normal gas emission properties in that it liberates its gas from the sorptive bond more quickly. There is a risk of outburst when the flow of metha¬ne originally desorbed by the coal is sufficient to move the loosened coal which has been broken suddenly. The violence of a gas/coal outburst can be evaluated from the distance of projection of the mass of coal. It depends on the gas pressure and on the liability to outburst of the coal at the original centre of the outburst. Both factors are complementary in their effects so that the same work is done in a gas/coal outburst when there is a high gas pressure and low proneness to outburst as when there is a low gas pressure and a higher proneness to outburst. The gas pressure in the coal increases with its gas content. Consequently it is possible to deduce the gas pressure of a coal seam from its gas content. In the Federal Republic of Germany the risk of a gas/coal outburst is thought to exist when the desorbable gas content of the coal reaches or exceeds the value of 9 m3/ton and if the specific limit value of the proneness to outburst is exeeded. The Mine Ventilation Testing Station of the Westfalische Berggewerkschaftskasse has developed a new method for determining the risk of gas outbursts immediately after taking the samples at the coal face (1), (2).

Jan 1, 1980

By Fred N. Kissell

Work done by Foster-Miller Associates under a Bureau of Mines research contract has developed methods to increase significantly the amount of fresh air that reaches the front of a continuous-mining machine. The emphasis was on removing methane build- ups that occur at the cutterhead. Using a full-scale plywood mockup of a coal mine working face area, the study showed that in many instances only about 20 pct of the fresh air heading towards an exhaust brattice or tubing actually gets to within 1 ft (0.3m) of the face. The key to providing more air at the face is to enhance and move forward the natural airflow pattern. This change in the natural airflow pattern can be accomplished by taking advantage of the air-moving abilities of the conventional water spray. It was discovered that if all the water sprays on the machine were realigned, then ventilation efficiencies of 70 pct or more were achieved regularly. This meant that if 9,000 cfm (4.2 m3/s) was entering the brattice, at least 6,300 cfm (3.0 m3/s) of this was reaching to within 1 ft (0.3m) of the face. This water spray realignment consists of placing a few nozzles on the side of the machine opposite the curtain and also tilting the front sprays slightly towards the curtain side. Recently, two underground tests and two additional independent laboratory tests of the water "Spray Fan" have been completed. In general, they have confirmed the performance of the Spray Fan system, but they also have provided useful information as to its difficulties and limitations.

Jan 1, 1980

By Joe Rigney, Conrad Stacey, David Nowak, Chris Blanchard, Michael Beyer, John Czach

Originally constructed in the 1930s, the 1-mile-long Sumner Tunnel is 31 feet in diameter and carries traffic deep below Boston Harbor, connecting Boston and East Boston. This project includes both design and construction for the rehabilitation of the nearly 100-year-old tunnel. The primary work includes repairing advanced deterioration at the tunnel crown with new precast arches that will add protection and strengthening. The restoration also consists of upgrading the tunnel systems, including permanently removing 75% of the existing exhaust duct suspended over the roadway to improve the overall ventilation system capacity and performance.

Jun 23, 2024

By N. S. Tanious

Three water-spray ventilation systems were tested to determine their effectiveness in diluting methane at a room and pillar coal mine face. These systems were: the shrouded nozzle, the spray fan, and the conventional nozzle system that is normally supplied with continuous miners. The testing was carried out in two stages. The air-moving capacities of the nozzles were first evaluated in a duct. The duct tests showed that: (1) the volume of air moved by the nozzle is controlled by the type of nozzle, the space around it, and its location relative to the duct wall; (2) the spray fan nozzles or the shrouded nozzles are both capable of moving air quantities up to 6400 cfm (3.02 m3/s); and (3) when the shroud was removed from around the shrouded nozzle, its bare nozzle moved between 9 and 65 percent more air. In the second stage of testing, a full-scale evaluation of the three systems was conducted. The three spray systems were mounted on a continuous miner which was positioned in an aboveground simulated mine entry. The simulated face tests gave the following results: (1) the standard nozzle system, which is mounted on the front end of the miner, is inadequate for diluting methane; (2) under the best testing conditions (lowest methane emission rate, highest primary ventilation airflow, and closest brattice set back), the slight improvement given by either the shrouded system or the spray fan is the same; and (3) under the worst testing conditions (highest methane emission rate, least primary ventilation airflow, and farthest brattice set back), the spray fan gave superior performance.

Jan 1, 1987

By Larry Snyder, Levent Ozdemir, Charles Fishman, Fun-Den Wang

Tunnel Boring Machine Instrumentation A 9.17 m. diameter tunnel boring machine presently in operation in Chicago, Illinois, has been instrumented to continuously monitor and record machine thrust, torque and penetration rate during boring. A micro-processor-based data logger capable of monitoring up to 60 channels of data digitizes and converts into appropriate engineering units the signals from various transducers mounted on the machine. The output from the data logger is sent to a teleprinter, providing a permanent record of measured data. The program control enables the data logger to scan all data channels at desired time intervals. Data obtained to date have been analyzed to determine the interrelationships of the parameters measured. Penetration rate was found to increase linearly with machine thrust with a unit increase in thrust causing more than a unit increase in penetration rate. For low thrust levels corresponding to the initial stages of a boring cycle, the penetration rate was observed to behave erratically until the thrust pressure was sufficiently high for the cutters to establish full contact with the tunnel face. Torque showed a curvilinear increase with machine thrust, reaching the design rating at about 70% of maximum available thrust. No-load torque was approximately 20% of the machine's rated torque capacity. Overall, the trends observed in measured machine parameters correlated closely with those predicted from experimental and theoretical boreability studies. In summary, the instrumentation system has mett two basic goals. First, it provided extensive and accurate boring data and secondly, it has proven that an automatic data acquisition system can be installed on a TBM and can function under adverse environment.

Jan 1, 1979

By Faruk Oksuz, Dave Schiemann, Miguel Sanchez, Patrick Jensen

"The McCook Main Tunnel connects Chicago’s Tunnel and Reservoir Plan (TARP) Mainstream Tunnel to the McCook Reservoir. The tunnel system consists of a 10 m (33 ft) finished diameter and 490-m (1,600-ft) long hard-rock tunnel constructed from a 27.5-m (90-ft) diameter and 92 m (300 ft) deep main gate shaft. The gate shaft houses six high-head 4.4 x 9 m (14.5 x 29.5 ft) wheel gates installed in the bifurcated and steel-lined section of the tunnel. The tunnel also includes portal and energy dissipation structures as it daylights into the reservoir. Construction of the McCook Main Tunnel in live flow conditions was a challenging task for the McCook Main Tunnel Project participants, the project owner U.S. Army Corps of Engineers (USACE), local sponsor Metropolitan Water Reclamation District (MWRD) of Greater Chicago, designer Black & Veatch and contractor Kiewit Infrastructure Co. (Kiewit). Once completed in two stages in 2017 and 2029, the McCook Reservoir will hold 38 billion L (10 billion gal) of combined sewer overflows (CSO) and flood waters from the city of Chicago and 36 surrounding communities in Cook County, IL The construction of the tunnel system was divided into two contracts. The first contract for the gate and construction access shaft was completed in August 2011. The second contract included tunnel excavation and concrete and steel lining that was completed in September 2014; installation of gates and hydraulic cylinders that was completed in June 2017; and the last major construction activity was the removal of a temporary concrete plug (bulkhead) and lining that tunnel section to bring the overall tunnel and gates system online before Dec. 31, 2017.This article focuses on the installation, testing and commissioning of the high head wheel gates. Live tunnel connection details to TARP Mainstream Tunnel were addressed in a previous paper submitted at the World Tunneling Conference in 2016."

Mar 1, 2019

By Gail B. Knight

INTRODUCTION In May 1984, The Canadian Pacific Railway awarded to the Joint Venture of Foundation of Canada, Ltd. of Toronto, Atlas Construction Co. of Montreal, and S. A. Healy Co. of Chicago the contract for the construction of 27,000 ft of tunnel starting from the east portal. Selkirk contractors, the Joint Venture of Foundation, Atlas and Healy, which had successfully completed for CPR in 1983 the construction of both portal structures for this tunnel, studied several different alternative proposals before presenting its bid pooling each individual company's technical resources and experiences. (Foundation had just completed in association with other companies a similar tunnel project in British Columbia, and the S. A. Healy Co. could provide its experience of more than 40 miles of tunnels excavated by full face boring machines.) Among the alternatives investigated there was a fully circular tunnel to be excavated by a 30 ft diameter TBM, a full section drill and shoot proposal, and a mixed alternative, the "key hole" proposal, consisting of a TBM driven circular top heading followed by benching to design size. Technical, geological and economical considerations determined the alternative that was eventually proposed to CPR. HISTORICAL NOTES The tunnel construction parallels an existing tunnel through the Selkirk mountains that was excavated in 1885. In order to reduce the grade to 1% on the heavily loaded west bound trains, the new tunnel was at a lower elevation and lengthened to almost 9 miles. GEOTECHNICAL INFORMATION CP Rail site investigations began in 1978. The surface rocks in the tunnel construction area are metamorphosed Cambrian and Pre-Cambrian sediments; the underlying formation contains fine and coarse grained rocks presenting different degrees of metamorphism. The

Jan 1, 1987