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Numerical modelling is a valuable tool for simulating the fundamental processes that take place during a heating. The models presented in this paper have enabled a quantitative assessment of the effects of initial pile temperature, pile size and mass and coal particle size on the development of a heating. All of these parameters have a certain criticality in the coal self-heating process.

Jan 1, 2005

By B. C. Scott

Every year more and more mining companies are entering joint ventures to look for minerals. Large companies join large companies, small companies join small companies, and large companies join small companies. Mining companies join oil companies, chemical companies, machinery companies, and companies with no other connection to the minerals business. And well they might, for here is a way for both minerals-oriented companies and those that have no background or knowledge of the minerals business to get actively involved in an outwardly-attractive but high-risk enterprise with the chance to participate in a lucrative minerals find. Thus, for reasons beyond those normally associated with joint ventures in many other fields, corporations, companies, groups, and even individuals are looking to joint exploration ventures as the answer to all problems of getting into or staying in mining.

Jan 1, 1972

By S. Fairis Samuelson

Boling Dome. a piercement salt dome in the Texas Gulf Coast basin is (was) the single largest deposit of native sulfur in the Western world. Total sulfur production has been over 81.000,000 long tons and the mine is still in production. Data from over 60 years of operation and 8.000+ wells reveal a salt dome rich in history as well as minerals. Sulfur mineralization and production correlate well with caprock structure and morphology. The occurrence of Mississippi Valley-type deposits in fracture zones is notable in some areas and may warrant additional study. DISCOVERY AND PRODUCTION HISTORY Boling Dome is located in the south- east corner of Wharton County, Texas, 60 miles south-west of Houston. It is a piercement type dome in the Houston diapir province. It was discovered in 1922 when the county surveyor noticed sour gas seeps along the San Bernard River (Haynes. 1942). Several companies including Gulf Production Company. Humble, Texas Company, Sun and others quickly began drilling for oil and gas. Traces of native sulfur were reported in cuttings from many wells penetrating the caprock, but the first commercial quantities of sulfur were not found until Gulf Production's E.M. Chase 3 and 4 wells were drilled in 1927. Texas Gulf Sulphur, then mining sulfur at Gulf Dome in Matagorda County, secured the sulfur rights from Gulf for $3 million in cash and half of the profits after expenses for development and construction of plant and townsite were met (Haynes, 1942). The drilling results from 200 or so Wells revealed a massive deposit destined to become the largest single source of native sulfur in North America. Original reserves were estimated at just over 46 million long tons and were increased in later years. Production by the Frasch method was begun by Union Sulphur in 1928, and continued by Texas Gulf Sulphur Co. in 1929, and Duval Sulphur Co. and the Baker Williams Co. in 1935. Union produced 8,009 long tons, Duval produced 571,123 long tons, and Baker Williams produced 1,453 long tons. Through its deal with Gulf, Texasgulf acquired the largest and best mineralized portion of the dome and has produced 88,544,466 long tons through 1990, and production is planned for several more years. That amount of sulfur is equivalent to a cube measuring 1,152 feet on each side, or a sulfur highway 1 foot thick, 20 feet wide and 14,479 miles long. Peak production averaged 8,376 ltpd in 1948. A price war between North American sulfur producers and Mexican sulfur producers in 1956, followed by the recession of 1957 and 1958 (Haynes, 1959) coupled with a rapid increase in mining depth to below 700 feet began a gradual production decline that was never reversed (Figures 1 and 2).

Jan 1, 1992

By Brian E. McGee

The Federal Coal Management Program represents the culmination of several years of effort by the Department of the Interior (001) to reformulate the manner in which coal owned by the United States is leased and developed. These efforts began in 1970 with a study by the Bureau of Land Management (BLM), which indicated that unless drastic changes were made in. the federal coal leasing procedures, federal coal lands would be leased almost for the asking while production of coal from those lands had been decreasing. Consequently, informal action was taken in 1971, which resulted in no further leasing being authorized until February, 1973. At that time, a formal moratorium on most coal leasing was established, with exceptions granted only for leases needed to satisfy short-term needs such as maintaining existing mines or supplying reserves for new contracts in the immediate future. This leasing policy embodied a long term objective of developing an entirely new planning system for federal coal leasing, as well as to schedule the preparation of a programmatic impact statement for this new system. As a result of the 1973 moratorium and the ensuing application of short-term criteria, only 10 federal coal leases (covering approximately 30,177 acres) were issued from February, 1973, through January l, 1976.

Jan 1, 1982

By M. R. Rosen

A technique is presented for simple characterization of the performance of flocculents in various mining applications. The method utilizes three key parameters obtained from raw settling data and combines them into a single athematical parameter called the desirability coefficient. The first two parameters are the timesrequired for the slurry-supernatant interface -to fall to two selected fractions of the starting height, and the third is the clarity of the supernatant liquid. The relative values of the three parameters may be assigned different weights in order to make them correspond with laboratory and field performance requirements of a particular industry. Provision is also made of an, internal comparison of test flocculant data with that of a control.

Jan 1, 1980

By R. Stefanko

Rock bolting as a method of support continues to increase with applications in many other industries in addition to mining. Nevertheless, with nearly 55,000,000 roof bolts installed in coal mines alone last year, this remains as the single greatest use. While bolts have frequently supported ground where conventional timbering could not, there are relatively few design criteria; and trial-and-error procedures prevail. Furthermore, development of suitable instrumentation that is simple to install and readout, sensitive, durable, reliable, safe and economical in evaluating the effectiveness of a bolt over long periods of time lags behind. Therefore, the pull test continues to be the most popular method of evaluating the applicability of a certain type of roof bolt under specific installation conditions. At Penn State in the Department of Mining, research has been conducted for a number of years to measure bleedoff in carefully controlled laboratory experiments as well as in underground investigations.1,2,3,4 Unfortunately, most of the instrumentation developed has been primarily suitable only for research purposes, not possessing all of the aforementioned characteristics desirable for routine underground use. Other groups also have met with restricted success. Therefore, while relatively crude, the torque wrench continues to remain as the most widely used load measuring device. While both field and laboratory tests continue to be conducted, analytical analyses are attempted to discover the more important design parameters in order that more efficient anchorage might be devised.

Jan 1, 1969

By David C. Oyler, Dennis R. Dolinar, Christopher Mark, Craig S. Compton

Fully-grouted roof bolts comprise more than 80% of the primary roof supports used in U.S. coal mines. However, nearly 1,500 MSHA reportable, non-injury roof falls occur each year, and most of these are attributable to failure of the roof bolt system. Anchorage failure is one failure mechanism for fully-grouted bolts. As roof deformation works its way upward, the bolts can become heavily loaded near their upper ends. If the applied load exceeds the anchorage, the bolts will simply pull out. Research dating back 30 yrs indicates that this type of anchorage failure is most likely when the roof rock is weak, just where roof support is most critical. In soft shale or coal roof, the small amount of data available in the literature indicates that 20-30 in of resin anchorage may be required to achieve the full capacity of the bolt. In other words, the “full resistance zone” of a 60 in bolt may actually be just 30-40 in. Despite its potential importance, there is no widely accepted anchorage test for fully grouted bolts. Standard pull tests have sometimes been employed, but they provide no information on the anchorage near the top of the bolt. An alternative, first described more than 25 yrs ago in the U.S., is the short-encapsulation pull test (SEPT). With this test, the bolt is installed with only a short (1 ft or less) tube of resin. In recent years variations of this test have become international standards. v

By Chris Mark

Fully-grouted roof bolts comprise more than 80% of the primary roof supports used in U.S. coal mines. However, nearly 1,500 MSHA reportable, non-injury roof falls occur each year, and most of these are attributable to failure of the roof bolt system. Anchorage failure is one failure mechanism for fully-grouted bolts. As roof deformation works its way upward, the bolts can become heavily loaded near their upper ends, If the applied load exceeds the anchorage, the bolts will simply pull out. Research dating back 30 yrs indicates that this type of anchorage failure is most likely when the roof rock is weak, just where roof support is most critical. In soft shale or coal roof, the small amount of data available in the literature indicates that 20-30 in of resin anchorage may be required to achieve the full capacity of the bolt. In other words, the "full resistance zone" of a 60 in bolt may actually be just 30-40 in. Despite its potential importance, there is no widely accepted anchorage test for fully grouted bolts. Standard pull tests have sometimes been employed, but they provide no information on the anchorage near the top of the bolt. An alternative, first described more than 25 yrs ago in the U.S., is the short-encapsulation pull test (SEPT). With this test, the bolt is installed with only a short (1 ft or less) tube of resin. In recent years variations of this test have become international standards. This paper describes recent studies using short encapsulation pull tests in the U.S. Tests were conducted in the National Institute for Occupational Safety and Health (NIOSH) Safety Research Coal Mine at Bruceton and at underground mines in Pennsylvania and West Virginia. The study found that the SEPT can be used to make a simple evaluation of resin bolt anchorage. Suggested procedures for conducting SEPT are included. The study also confirmed that poor anchorage can be an issue, particularly where the roof rock is very weak. Some simple techniques for improving anchorage, and thereby the effectiveness of fully grouted bolts, are discussed.

Jan 1, 2002

By Claudio Asioli

"The project’s goal was to construct the Al Ghazala Intercontinental, a multi-use development in the bay area of Tripoli overlooking the Mediterranean Sea. The site of the project is located approximately 500 ft (150 m) from the Mediterranean coast, near the Al Ghazala roundabout in the town center of Tripoli, Libya. The investor of the project was Magna Properties Group, Ltd. – Libya, the main contractor was Man Enterprise S.A.L., and the design and construction management was performed by Dar Al-Handasah Engineering. Trevi S.p.A. was contracted to perform the design and construction of the anchored diaphragm walls and dewatering systems for the excavation of a two-level basement car park, which extends across the full footprint of the site.The site was approximately 640 ft by 230 ft (195 m by 70 m) in plan and nearly flat. The groundwater level typically varies from about 11 ft to 23 ft (3.4 m to 7.0 m) above mean sea level. To construct the required raft foundation, it was necessary to excavate the area down to El. -15.7 ft to -26.3 ft (-4.8 m to -8.0 m), which resulted in an excavation depth ranging from about 27 ft to 39 ft (8.3 m to 12.0 m) below the existing ground surface.Subsurface ConditionsThe subsurface site investigation was performed in three phases by Al-Tamier Engineering Consulting Bureau. During Phase 1, a preliminary investigation was undertaken during the early stages of the project to obtain information about the general stratigraphy and groundwater level at the site. Phase 2 was performed to obtain subsurface information and design parameters, and Phase 3 was performed as a supplementary ground investigation to investigate unexpected ground conditions identified during Phase 2. In total, 14 boreholes were drilled to depths ranging from about 80 ft to 180 ft (24 to 55 m). The generalized subsurface profile is quite heterogeneous, and is predominantly composed of sand with silt and gravel that is underlain by limestone, calcarenite and claystone"

Jan 1, 2017

By Claudio Asioli

"The project’s goal was to construct the Al Ghazala Intercontinental, a multi-use development in the bay area of Tripoli overlooking the Mediterranean Sea. The site of the project is located approximately 500 ft (150 m) from the Mediterranean coast, near the Al Ghazala roundabout in the town center of Tripoli, Libya. The investor of the project was Magna Properties Group, Ltd. – Libya, the main contractor was Man Enterprise S.A.L., and the design and construction management was performed by Dar Al-Handasah Engineering. Trevi S.p.A. was contracted to perform the design and construction of the anchored diaphragm walls and dewatering systems for the excavation of a two-level basement car park, which extends across the full footprint of the site.The site was approximately 640 ft by 230 ft (195 m by 70 m) in plan and nearly flat. The groundwater level typically varies from about 11 ft to 23 ft (3.4 m to 7.0 m) above mean sea level. To construct the required raft foundation, it was necessary to excavate the area down to El. -15.7 ft to -26.3 ft (-4.8 m to -8.0 m), which resulted in an excavation depth ranging from about 27 ft to 39 ft (8.3 m to 12.0 m) below the existing ground surface. Subsurface ConditionsThe subsurface site investigation was performed in three phases by Al-Tamier Engineering Consulting Bureau. During Phase 1, a preliminary investigation was undertaken during the early stages of the project to obtain information about the general stratigraphy and groundwater level at the site. Phase 2 was performed to obtain subsurface information and design parameters, and Phase 3 was performed as a supplementary ground investigation to investigate unexpected ground conditions identified during Phase 2. In total, 14 boreholes were drilled to depths ranging from about 80 ft to 180 ft (24 to 55 m). The generalized subsurface profile is quite heterogeneous, and is predominantly composed of sand with silt and gravel that is underlain by limestone, calcarenite and claystone."

Jan 1, 2017

By Chu E. Ho, Paul Napoli

A new waterfront park was developed on Long Island in close proximity to the East River and Newtown Creek. The existing ground consisted of fill over soft organic clay, medium dense silty sand, glacial till and schist bedrock. The ground was initially raised to preload the underlying soft soils to stabilize the ground in preparation for site development. The ground was subsequently cut down to temporary grades for installation of foundation piles for the overlook structures and construction of reinforced concrete cantilever retaining walls forming pathways located adjacent to the water bodies. The retaining walls were located in two rows at different elevations along the sides of a steep embankment. Where the pathways converge, some of the walls were too close to each other, and were redesigned as a combined U-wall with a common base slab. The individual retaining walls were designed for adequate bearing, sliding and overturning resistance. Ground anchors were installed to enhance global stability of the retaining walls. This paper presents the design considerations for the retaining walls for various loading conditions, and evaluation of the trial and proof tests for the anchors. INTRODUCTION The New York City Master Plan included the transformation of an approximately 30-acre parcel of land in Long Island City, Queens, New York from a former manufacturing zone into a residential, commercial and recreational zone for middle-income community. The site was located at Hunters Point South along the eastern shoreline of the East River and Newtown Creek (Figure 1). The development included low to high- rise residential buildings, a public school, and retail structures. Open spaces were provided along the East River and Newtown Creek waterfronts in the form of a continuous park providing for recreational and community-related activities. Waterfront structures included small park buildings, walkways and viewing platforms. The shoreline was surrounded by revetments as part of the flood mitigation strategy. The project involved extensive site re-grading and several retaining walls were constructed. The earthwork volume amounted to approximately 47,000 cubic yard of imported fill and 93,000 cubic yard of cut. The exposed height of the retaining walls ranged from 3 to 15 feet. This paper focuses on the design and construction of the retaining walls for the project.

Jan 1, 2019

By Seth L. Pearlman

A major excavation support case history for the Eastern approach to the Third Harbor Tunnel (THT) in Boston, MA is described, which uses an anchored Soil Mixed Wall (SMW). Both general and project specific information is provided regarding the design and construction of SMW walls. In addition, conclusions are presented that discuss the suitability of this particular application and other possible variations.

Jan 1, 1993

By Marco D. Boscardin, Benjamin H. MacKinney, Kenneth R. Allard, Kenneth A. Pidgeon, Adriane G. Boscardin

This paper presents a case history for a unique application of a system of vertical micropiles with horizontal soil nail bracing and shotcrete facing for underpinning. The system was used to support and protect an existing 2-story hospital building during demolition and renovation. The goal was to limit building movements and have the building remain in use during construction of an abutting addition. Soils at the site consisted of clean, loose to dense, sand and gravel. The original underpinning design was revised after the initial excavation revealed unsuitable soil conditions for traditional underpinning pits. An alternative system consisting of vertical micropiles (hollow bars) through the footing, combined with shotcrete and soil nails was proposed, accepted by the owner, and successfully constructed. Excavation depths were up to 15 feet (4.6 m) below the existing footings. Wall movements were monitored at regular, horizontal and vertical intervals along the hospital wall, and less than 0.6 inches (15 mm) of settlement and 0.1 inches (3 mm) of horizontal displacement throughout underpinning and construction were reported. The challenges with the original proposed support of excavation design and other alternative approaches considered will also be discussed.

Oct 1, 2022

By Cory J. E. Yacyshyn

Anchored steel pipe piles are being used more frequently in British Columbia for shoreline projects such as public ferries, cruise ship docks, containership terminals and locally in the expansion of the Vancouver waterfront convention center. While a 36? diameter driven pile may provide adequate compression loads it will not always achieve enough penetration to provide the required tension loading. That is why bundles of threaded anchors or strands are drilled through the center, past the pile tip, and anchored into the underlying strata. Drilling up to 250 feet deep through the piles in variable water bearing strata presents challenges. Southwest Contacting Ltd. (SWC) recently completed the three largest anchored pile projects in BC; Vancouver Port and Convention Center Expansion, Vanterm Container Terminal and the new Prince Rupert Cruise Ship Terminal. This paper will present the separate challenges encountered drilling the anchors. At Prince Rupert, the recently completed Northland Cruise Ship Dock ultimately required a cased system to drill and install triple thread bar anchors. When 200 foot long steel pipe piling was unable to penetrate the highly fractured gneiss/schist bedrock to obtain a seal and consolidation grouting was unsuccessful, a modified cased system was advanced deep enough into the rock to eventually seal. The 3-#20 bars were changed to 12-strands since the bars wouldn?t fit through the smaller cased hole. The options were limited because each dolphin only had enough room for a small hydraulic drill rig that wouldn?t have the power to fully case the holes. The Canada Place Pier Extension in Vancouver?s Harbor led to the development of an innovative tip design used later at Vanterm. The 36? diameter steel pipe piles were driven closed end but modified to permit drilling through a concrete plug at the base. The driving of the piles at Canada Place often knocked out the plug so we were faced with 50 feet of sand up inside the pile when the drilling started. This led to discussions on how to safely remove the sand, solidify the tip, and continue drilling to get past the tip without undermining the pile. Finally, Vanterm Berth Extension was completed with a unique drilling system because the pile tips stopped in hydraulic sands, as opposed to the native till. We were faced with advancing the casing to the till without undermining the base of the pile. With 100 psi water pressure at the pile base after we broke through the concrete plug, the trick was to prevent charging the sand with our 250 psi air which liquefies it and forced it up our drill casing. And of course, it has to happen just before Christmas holidays!

Jan 1, 2004

By Andrew Pontecorvo

The design of foundations for the tall buildings of lower Manhattan rely on the use of high capacity, rock anchors to resist overturning forces generated by lateral loads from wind, earth, water and, to a lesser degree, seismic forces. Once completed, the proposed towers at the World Trade Center (WTC) site will be among the tallest buildings in New York City. The towers are exposed to coastal winds and from several levels of below grade structure soil and water loads. The design loading required under the current New York City Building Code (NYCBC) is similar to the requirements of the building code used to design the original WTC Twin Towers. We will compare how rock anchors were deployed in the Twin Towers and how they are used in the new buildings. Changes to the building code are less significant that the changes to the design of the structure; that is how the outer skin or perimeter structure interacts with the building core. The result is a significant increase in the number of rock anchors required for the new buildings when compared to those installed in the original WTC Twin Towers.

Jan 1, 2011

By George Brien, O&apos

The history of the lighting of mine workings dates back to the early part of the 18th century, when small candles known as tallow dips, were used. These were set or held in a lump of wet clay. When looking for gas the flame of. the candle was reduced to a mere glimmer by surrounding the wick below the flame with clay. The candle was then very cautiously raised from the floor toward the roof, the observer screening the brighter portion of the flame with his hand and watching for the first appearance of the pale blue cap above the flame, even at that time, known to indicate the presence of gas. When this appeared the candle was lowered quietly and its flame extinguished before attempting to drive out the gas. A very common and dangerous practice adopted at that time was to get rid of the gas by firing it. This was done by a person selected for his nerve rather than for his caution. Dressed in a? suit of dampened sackcloth or leather, this man well termed a "fireman", would lie prone on the floor of the roadway and light the gas above him by raising his candle fastened to the end of a long stick. If he survived, which was not always the case, he would withdraw promptly to fresh air after the flame had passed over him.

Jan 1, 1924

By Mark Alling

INTRODUCTION A FEW years ago, gravel mining in the ancient river beds of Sierra county was the principal industry of the county. Operating drift mines were very numerous and many large hydraulic mines were in action. Eventually the State laws put an end to hydraulic mining, it being claimed that the silt carried down the streams to the valleys filled the rivers and caused winter floods, which were damaging to the surrounding farms. The ancient river deposits which could easily be found were, in the course of 40 years, worked out or practically so. The prohibition of hydraulic mining was a severe blow to the industry in general. The deposits were not developed and the gravel-mining industry practically stood still for many years. In Sierra county, nearly all the hydraulic mines were at the points where the ancient channels were exposed to view by reason of the modern stream erosion, or, in the miner's language, where the channels "enter" or "break out of" the ridges. The claims covering them also covered large areas in which were long segments of lava-capped channels, suitable for drift mines, and the points being hydraulicked were usually the controlling points of attack. Men who have followed hydraulic mining for any length of time seldom are content to work a drift mine. Knowing the great value of their deposits and feeling that they had been robbed by the State, these men have stubbornly held to their claims. The gold that is carried in these gravel channel deposits is more or less scattered throughout the depth and width of the deposit; the percentage that can be recovered by the process of drifting ranges from 50 to 75 per cent. of the total. In hydraulicking, practically all of the deposit is put through the sluices, and as the cost per cubic yard is only about 10 per cent. of the cost of drifting, the deposits, if classed as hydraulic mines, are much more valuable than if classed as drift mines; hence the old timers have held their claims (now worthless as hydraulic mines) at prices which the drift-mining industry could not stand; and such mines

Jan 7, 1914

By F. E. Gregory

MINING methods and customs in many districts of England are to this day strangely bound about by the records and traditions of the past. In some mining fields this is more apparent than in others, yet it is everywhere in evidence, for Cornwall with her mines under the sea, Wales with her famous quartzites, and Derbyshire with her remarkable cavern deposits, are all tinctured with quaint customs that have come out of the almost forgotten past. Here, modernism has never replaced tradition, and many of the laws are woven of the woof and warp of ancient custom. Indeed, these things exist because they have come to be part and parcel of the civil laws. And these laws are observed with meticulous care and accorded all the reverence due their venerable age. All activities pertaining to the mining of metals are hedged around by curious and ofttimes clumsy laws, each minute and trivial detail being covered by the civil code, and each petty law enforced by an ofttimes pompous official.

Jan 1, 1933

By John W. Trammell

The White Pine Mine is situated in Ontonagon County, approximately six miles south of Lake Superior, in the Upper Peninsula of Michigan (Figs. 1 and 2). The ore body mined by White Pine Copper Company occurs in the lower - most 20 to 25 feet of the Nonesuch formation, a series of middle - to upper Keweenawan shales, siltstones, and sandstones. This paper elaborates on the solution of problems in ore grade control and mine planning arising from the presence of an essentially barren sandstone stratum within the ore body.

Jan 1, 1964

By M I. Pownceby, S Hapugoda, H Han, V Nunna, L Lu

Charcoal produced from Syzygium Zeylanicum (local name: Yakada Maran = iron killer) trees were widely used in ancient Sri Lankan iron smelting practices. In this study, relict charcoal from Syzygium Zeylanicum tree trunks, branches and leaves were analysed for the first time. Unusually high concentrations of calcium oxalate (CaC2O4.H2O – CaOX) crystals were identified preserved in plant cell structures by optical mineralogy and SEM analysis. Thermogravimetric Analysis (TGA) of CaOX showed that it displayed three decomposition stages, releasing H2O at 177°C, CO at 493°C and CO2 at 750°C. Following the identification of CaOX in Sri Lankan charcoal, a series of reduction tests on a low-grade, high-P iron ore fine sample (high SiO2: 5 wt. per cent; Al2O3 4 wt. per cent; P: 0.135 wt. per cent) doped with CaOX were carried out at various temperatures. Samples were analysed by XRF, SEM and EPMA to determine the degree of reduction and the effect of reduction on the deportment of impurities, in particular P. Reduction tests at 800°C and 900°C with 5 wt. per cent CaOX showed that the reducibility increased to over 65 per cent. At temperatures above 900°C, P was located mainly within a fine, interstitial glass matrix suggesting that the CaOX flux enhanced removal of P from iron-rich pre-cursor phases to form glass. Preliminary magnetic separation tests to remove the P-rich interstitial glass were unsuccessful due to the fine grain size. Further complete reduction tests at temperatures above 1200°C with addition of coke to convert the iron oxides into Fem were conducted with samples doped with 10 wt. per cent CaOX, 10 wt. per cent CaCO3 and equivalent undoped samples. Results confirmed the preferential P-incorporation into a glassy matrix in the CaOX samples although some rare P incorporation into the metallic phase was noted. Experimental results, including comparisons with the CaCO3 fluxed and undoped samples, are discussed in view of the potential for CaOX flux for removing P (and potentially other impurities) from P-rich iron ores.

Nov 8, 2021