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By Jon Y. Kaneshiro, Donald W. Scapuzzi

The primary purpose of the Prototype Installation Facility (PIF) for the Superconducting Super Collider (SSC) in this conceptual design was to test the magnets and other physics equipment. PIF was located in the northwest quadrant of the SSC 54 mile (87 km) main ring and consists of the first segment of tunnels, approximately 17,060 lineal feet (5.2 km) of 12 foot inner-diameter (ID) (3.7 m) tunnel, three 250 ± foot (60 m) deep shafts, connecting tunnels, and associated niches and alcoves. PIF would be the first portion of the main ring collider tunnel to be constructed. The geology, underground excavation conditions, underground facilities, and contractual considerations are discussed.

Jan 1, 1991

By John J. Mulligan

Coal is found in every major geographic region throughout Alaska and in two offshore areas. Since about 1852 over 100 small mines have opened and closed. Last years production was almost entirely from one mine in central Alaska. Clearly the utilization of Alaska's abundant coal resources presents political, economic and technical problems that are far from solution. Location and Physical Features Figure one illustrates the geographical and geological similarity between Alaska and western United States. The Arctic region of Alaska generally resembles Wyoming and the Dakotas. The Brooks Range is an extension of the Rocky Mountains. The Central region of Alaska between the Brooks Range and the Alaska Range bears a general resemblance to the basin and range country of western United States. The Southcentral and Southeastern regions has a similar resemblance to the Sierra Nevadas and the west coast of the United States.

Jan 1, 1982

By R. R. Tatiya

This paper describes the local estimation of mineral inventory by kriging. A mineral deposit located between two working levels of a copper mine was examined. Data for this estimation was obtained by underground diamond drilling. The mineral inventory that was computed by this method was compared to the results obtained by global estimation techniques, which were based on information front surface boreholes. A comparison between the ore reserves estimated through kriging and the ore reserves estimated at the mine using conventional methods was also made. This analysis shows that geostatistical methods can be applied to evaluate base-metal deposits similar to the deposit examined in this study. In the part of the mine that was examined, the kriging estimates show an overall increase in metal content at all cutoff grades, compared to the estimates obtained through conventional methods. Also, the ore body profiles are more continuous and regular through kriging, but they are not radically different from the profiles that were previously obtained at the mine. However, the global estimate of the deposit using kriging could not provide reliable results.

Jan 1, 1997

By Horry Parker Jr, Jason Gillespie, Justin Kolster, Stephen O’Connell

Construction of the 5,932-ft Reedy River Basin Sewer Tunnel in Greenville, SC was marked by a critical transition from drill-and-blast mining in mixed-face conditions to TBM excavation with limited rock coverage. In this paper, we discuss the geological, geotechnical, and risk management considerations for transitioning to TBM operations in variably weathered gneissic bedrock. After construction of an unexpected 230-ft starter tunnel due to differing site conditions, the 11-ft diameter TBM was successfully launched in December 2019 without significant ground support issues. This project highlights the effectiveness of extensive rock probing to fully characterize bedrock topography prior to the TBM launch.

Jun 13, 2021

By Allan Rocas, Aswathy Sivaram, Daniel Cressman, Tatiana Chiesa

The City of Toronto plans to construct a 1,350 mm consolidation sewer along the East Don Roadway (EDR). The project includes installation of approximately 260 meter of 1,350 mm diameter concrete pressure pipe through microtunneling methods. The sewer alignment crosses underneath a busy 5-lane arterial road and then follows the very narrow East Don Roadway road allowance. This paper discusses the significant challenges overcome to design the Don Roadway sewer using slurry microtunneling methods through mixed face conditions below the groundwater table in a congested road allowance. A curved microtunnel was ultimately required to avoid conflicts with existing utilities, condominium tiebacks and a bridge structure.

Jun 13, 2023

By D. I. Hoyer

A preliminary model has been developed for autogenous pebble milling using information obtained from studies on ball milling and SAG milling. The model treats the breakage as the weighted sum of first-order breakage of smaller particles by tumbling pebbles, non-first order breakage of larger particles which are too large to be nipped properly by pebbles, autogenouS fracture and chipping of larger lumps to form pebbles, and autogenous fracture and abrasion of pebbles. The model includes the effects of residence time distribution, classification through the exit grate, and a mass transfer relation which describes the accumulation of fine material in the mill. Example simulations are given, based on breakage parameters determined from batch grinding tests in laboratory mills. fracture breakage and abrasion. In the development of these preliminary mass balance equations it will be assumed that breakage by fracture is first-order, but this assumption will be modified later in the paper. It will also be assumed that the residence time distribution of a long autogenous mill can be described by an equivalent series of m fully-mixed mills, with a classification action imposed on the mill contents by the discharge grate. Size distributions are expressed as a v2 geometric series, numbered 1 for the top size down to n for the fines, or "sink" interval. If the holdup in the mill is W then the rate of breakage of material in size interval i is given by SiwiW, where wi is the fraction of material in size interval i, and Si is -the overall specific breakage rate of size i material (fraction per unit time).

Jan 1, 1985

By Yueyue Ding, Yuanhui Li, Zhengrong Li, Pengfei Yu, Kunmeng Li, Zhipeng Xiong

The overburden responses in gently inclined orebody mining are different from those in horizontal orebody affected by the orebody dip angle. In particular, the mining-induced stress presents asymmetrical distribution characteristics spatially, resulting in stress concentration and large-scale pressure relief phenomenon in the surrounding rock. As a result, frequent ground pressure disasters such as roof collapse and barrier splitting occur frequently. Moreover, the ground pressure evolution law and the interaction between stopes in multistope mining are complex. The effective ground pressure control measures cannot be taken due to unclear understanding of the evolution of stress and displacement fields, justifying the investigation of the distribution and evolution of underground pressure for safe and efficient mining.

Jun 1, 2023

By J. R. Johnson, C. G. Stewart, D. K. Myers

INTRODUCTION Radon-222 is an inert, radioactive gas formed by the radioactive decay of radium-226, a long-lived member of the uranium-238 decay chain. Radium is present in varying amounts in virtually all soils and, on the average, about 36,000 pCi (1330 Bq) of radon per square meter of soil diffuse into the atmosphere each day (UN 1977). Radon decays with a half-life of 3.6 days through four short-lived daughters to lead210 and it is these short-lived daughters[ [Ra A, (218Po, t, = 3.0 min) , Ra B, (214 Pb, t;, = 27 min), Ra C, (214Bi, t] = 20 min) and Ra C1 (214Po, t] = 2.5 x 10-6 min)] ]which cause the major health hazard associated with radon (Bale 1951). Atoms of these daughters, either unattached or attached to the ever-present particles in air, are deposited on the surfaces of the respiratory tract; alpha particles emitted in their decay can result in large doses to the cells of the bronchial epithelium lining the respiratory tract. These daughters will be present in air in varying relative concentrations depending on the "age" of the air (time since radon emanated into it) and on the amount of mixing of radon and radon daughter contaminated air with clean air. [The practical unit developed to quantify the amount of radon daughters in air is the Working Level (WL). This unit was historically related to the equilibrium concentration of 100 pCi (3.7 Bq) of the short-lived daughters of radon in one liter of air (cf. Holaday 1969) and is defined as any mixture of the short-lived daughters in a liter of air that have a-potential alpha energy of 1.3 x 105 Mev (2.08 x 10-5J) in their decay to lead-210. The working level month (WLM) was developed along with the WL, and was defined as an exposure to one WL for a working month (170 h). This is equivalent to 2.2 x 107 MeV•h•L-1 (3.54 x 10-3 J.h.m-3). If the average breathing rate is taken as 1.2 m3.h•1 (ICRP 1975), then one WLM is equivalent to inhalation of 4.24 mJ of potential alpha energy.] It is now generally agreed that the inhalation of radon daughters is the major potential radiation hazard in uranium mining, and contributes a substantial fraction to the natural radiation exposure of the general population due to the accumulation of radon and radon daughters from natural sources in buildings. Radon daughter concentrations in modern mines are controlled by ventilation, and by blocking off old working areas (cf. Simpson, 1959). However, before the hazard from radon daughters was recognized, considerably higher concentrations of radon daughters were present in some uranium and non-uranium mines. These high radon daughter concentrations resulted in an increase in lung cancers in the mining population, and it is these results that are our main source of information on the risk of inhaling radon daughters. HISTORICAL REVIEW Many excellent reviews of the history of understanding the health effects of inhalation of radon daughters are available (see, for example, Hueper 1942, Lorenz 1944, Sikl 1950, Stewart 1964, Holaday 1969, Lundin 1971, Cross 1979) but a brief summary of some of the highlights in this area may be of interest. [a] 1556: Agricola describes an unusual and fatal chest disease occurring among underground miners in the region of Schneeberg and Joachimsthal (Jachymov) in the Erz mountains in Central Europe. (It is of some historical interest to note that Agricola's book was translated from Latin into English by a mining engineer and his wife; the engineer later became President of the U.S.A.) [b] 1879: Haerting and Hesse indicated that the majority of deaths among Schneeberg miners were due to lung cancer; the lung cancers in these miners (who were incidentally not cigarette smokers) were observed twenty to fifty years after they began working in the mines. [c] 1896: Discovery of natural radioactivity by Becquerel, followed by discovery of radon by Dorn in 1900. [d] 1924: Ludewig and Lorenser report high concentrations (400 - 15000 pCi or 15 - 570 Bq per liter) of radon in the air in the Schneeberg mines and suggest that radon could be responsible for the high rate of lung cancer among miners. However, the reason why radon should cause lung cancer specifically was still not really understood up to twenty years later (Lorenz 1944). High concentrations of radon in the air in the Joachimsthal mines were reported by Behounek in 1927 and a high incidence of lung cancer among Joachimsthal miners (similar to that among miners at Schneeberg, which is only some 30 km distant but in a different political district) was noted at about the same time (Sikl 1930; cf. Sikl 1950). It is estimated that about half of the Joachimsthal miners died from lung cancer and about half from silicosis and tuberculosis (Sikl 1950). [e] 1930's and 1940's: Radioactive ores are deliberately mined in the U.S.A., Canada and other countries primarily as a source of radium for medical purposes and for luminescent dials; other radioactive ores are mined as a source of several non-radioactive minerals, while extensive uranium mining did not begin until the late 1940's. [f] 1940: Based on crude epidemiology and dose calculations, Evans and Goodman propose 10 pCi L-1 as a maximum permissible concentration of radon in continued human exposure. This is the first known recommended maximum permissible concentration for radon. This recommendation was adopted by the U.S. National Bureau of Standards in 1941 and reconfirmed in 1953. [g] 1945: Mitchell identifies the short-lived daughters in radon as a likely cause of the increased lung cancers in the Schneeberg-Joachimsthal miners

Jan 1, 1981

By Fatima-Zahra Houmymid, Elena Chiriotti, Mahdi, Samy

"The Greater Paris projects involves the creation of a 200km extension of the actual public transport network on the close outskirt of Paris. In 2011, SYSTRA has been awarded the Engineering studies of a 20km underground section in the densely urbanized southeast quarter of the Parisian suburb. In order to both guide the TBM technology choice and identify and mitigate the risk due to soil settlement during tunnel boring, several analysis have been carried out and integrated into a Geographical Information System to share and manage this risk during the successive design phases of the project. The geological context‘s complexity and the Owner‘ requirements have led to the necessity of using an innovative analysis approach, leveraging both the numerical modelling analysis’s accuracy and the analytical method‘s ease of programming and implementation in a GIS, by the mean of the calibration of the analytical approach’ parameters on the FEM results.INTRODUCTIONThe Greater Paris Transport Project foresees the extension of the actual public transport network to the close outskirt of Paris through the extension lines 11 and 14, the creation of a circular new line around Paris - line 15 completed by lines 16 and 18 linking developing territories - and line 17 to Roissy-Charlesde- Gaulle airport.The SOCIETE DU GRAND PARIS (SGP) is the public institution that promotes this project and awards SYSTRA as Engineering for the 15th Line southeast section.Line 15th – South-East sectionIn 2011, the Owner SGP (SOCIÉTÉ DU GRAND PARIS) awarded to SYSTRA the preliminary and detailed design of a 20km-long underground section of Line 15, between the stations of Villejuif-Louis-Aragon and Noisy-Champs. The double-track, single-tube tunnel has an inner diameter of 8.5m (about 9.8m excavated diameter, 75m2 excavated cross-section). The tunnel is inserted in a densely urbanized context."

Jan 1, 2016

By W. R. SHAHAN, W. R. Reed, J. P. Rider

Roof bolter operators may be exposed to high respirable dust concentrations on continuous miner sections with blowing face ventilation when bolting is performed downwind of the continuous miner. One solution to reduce the high respirable dust concentrations is to use a canopy air curtain (CAC) to deliver clean air from a filtered blower fan directly to the bolter operators under the canopies. The influence of CAC installation on the airflow and dust dispersion around the location of the roof bolter operator can be evaluated by using computational fluid dynamics (CFD). 

By Mark William Johns

Carbon-in-pulp (CIP) is the preferred method of gold recovery om cyanided plp. However, other gold adsorbents (namely, ton-exchange resms) are being introduced to the industry as they are considered to have several advantages over carbon for the recoery of gold. A set of test methods have been developed by the industry to evaluate the quality of different carbons. owever, many ?f these tests are not applicable to evaluating ton-exchange resms. Hence, a need has arisen for a method to evaluate the different adsorbents. This paper introduces a philosophy to evaluate an adsorbent that results in an estimation of the capital cost and the operating cost associated with the adsorbent. Tests that have been devel­ oped to evaluate the ability of an adsorbent to adsorb gold (in­solutton . counter-current) and to evaluate the optimum adsorbent for a specific pulp (in-pulp batch) are introduced. A method of converting the test data into an economic dimension is present­ed. Case studies are presented to highlight the discussion.

Jan 1, 1996

By Rock M. Poulin, Bruce G. Moulton, Daniel E. Nowak, David T. Cass

The Yacambu Irrigation Tunnel Project of 34 km, 5 meter diameter circular and horseshoe section, has been under construction since the early 1970's. Notable among the excavation challenges is high ground cover of 3,000m creating large lithostatic pressures in the tunnel alignment with subsequent plastic flow of the ground in the tunnel walls. The tunnel may converge from small amounts to 1 or more meters of diameter over long sections. Several excavation techniques have been attempted but all without desired results. The paper proposes a new machine concept that uses the history of ground experience as its basis for design.

Jan 1, 1995

By Y. Topkaya, R. E. Johnson, B. R. Palmer, Jia-Jun Ke, Da-Ping Kang

The kinetics of the leaching of antimony oxide ore (Sb2O4) in aqueous hydrochloric acid solutions has been investigated. This dissolution reaction is a heterogeneous solid-liquid reaction. It has been found that the leaching temperature and the concentration of hydrochloric acid turn out to be the significant influencing factors on the leaching rate. The apparent activation energy for the leaching reaction was determined to be 63.5 W/mol within the experimental temperature region of 50O to 90O C. The experimental results indicate that the leaching process is controlled by the rate of the chemical reaction.

Jan 1, 1993

By T. L. Conley, J. J. Rozek

The $2 billion (A$) Melbourne City Link Project is one of the largest and most important metropolitan road developments ever undertaken in Australia. The project involves two three-lane vehicular tunnels totaling 5 km, constructed as deep as 65 m underground. The 3.4 km Burnley tunnel is one of the world's longest three-lane tunnels. The project is being delivered under a DBOOT [design-build-own-operate-transfer] process and all design and construction is performed to ISO 9000 standards. Tunnel excavation began in May 1996, and the tunnel will open to traffic in 1999. This paper focuses on the range of construction techniques utilized during construction.

Jan 1, 1999

By R. W. Smith, R. K. Mehta, X. P. Zheng, A. M. Raichur, M. Misra

Experimentation was per formed on the flotation of apatite and dolomite separately using anionic collectors in the presence of Mycobacterium phlei. Also, the flotation of mixtures of dolomite and apatite in the presence of anionic collectors and in the absence and presence of the bacterium were studied. It was found that M.phlei functions as a depressant for both minerals. However, it functions as a better depressant for dolomite than for apatite. Experimentation was extended to two different Florida dolomitic phosphate rocks. In this investigation a concentrate grade of less than 1.0% MgO was achieved with a 75% P2O5 recovery.

Jan 1, 1999

By Gary B. Hemphill

The 345 km long Taiwan High Speed Rail Project will connect the island’s two most populated cities, Taipei and Kaohsiung. Kaohsiung is the world’s third busiest port. The 23 km of alignment on Contract C230 requires the construction of 5,879 m of shallow mined tunnels ranging from 137 m to 1,285 m in length. All nine of these tunnels are mined using NATM methodology. Two of the tunnels, T01 and T08 are in the Toukoshan Formation. This paper will discuss the mining methods, ground support design, and the instrumentation installed to monitor and verify its effectiveness in the two aforementioned tunnels.

Jan 1, 2003

By Qiu Rongqing, Huang Kongxuan

This paper summarizes the results of treating arsenic­bearing refractory gold concentrates from six gold Mines of Chi­na by using bioleaching method and discusses the conditions of bioleaching processes. Results indicate that Thiobacillus fer­rooxidans T-3 Strain can intensely oxidize arsenopyrite, how­ever oxidation rate and degree differe considerably for different. During initial inoculation of 5 X 106 cell/ml. FeH contration generaly 4 -8 g/1. Sample size > 80 % - 3 20 mesh and pulp density 10 % ( w /v) and leaching time ,1 -- G clays, arsenic re­moval rate reached more than 80 % , Fe extraction ,10 - GO% desulfurization rate 30-45% after bacterial oxidation of 4-G days.

Jan 1, 1992

By John F. MacDonald, John W. Critchfield

This paper describes the shield excavation of twin transit tunnels, through soft ground, in downtown Seattle. The tunnels are 6.5 m (21.25 ft) diameter and 1525 m (5000 ft) long. Initial support consisted of expandable precast concrete segments, followed by a final lining of cast-in-place concrete. Waterproofing was provided by a PVC membrane installed between the initial support and the final lining. During the course of the excavation a variety of methods were used to control the ground and limit settlement. These included deep wells, vacuum well points, eductor wells, chemical grouting, compaction grouting, jet-grout underpinning, and extensive instrumentation.

Jan 1, 1989

By Leif A. Nordell, Philip E. Freeland

A paper discussing specification, methods, situations and results encountered in underground phase construction of the Rocky Mountain Pumped Storage Project near Rome, Georgia. The scope of work included excavation, rockbolt/shotcrete/wire mesh primary support and cast-in-place concrete lining of the (1) 216 m, top flared shaft, connecting 1.57 radian elbow, and 590 m tunnel to a 10.67 m finished diameter; (2) complex double bifurcation section; (3) excavation, support, installation and backfill concrete for three parallel, 135 m steel penstocks of 5.79 m finished diameter; (4) construction of a 43 m diameter reinforced concrete intake/discharge structure atop the shaft.

Jan 1, 1985

By Matthew Anderson, David Day, Paul Smith

"The Midwest is presently the focus for Combined Sewer Overflow (CSO) abatement in the United States (U.S.). Most of the EPA mandated utility and municipal long term CSO abatement programs in large metro areas in the Midwest such as Cleveland, Indianapolis, Columbus, Chicago, St Louis, Akron, Fort Wayne, Louisville, Kansas City, Omaha and Pittsburg use or will use deep tunnels for storage and conveyance of CSOs. This paper will compare design methods specified and implemented for tunnel construction in Midwestern geology such as soft ground and mixed face EPBM tunnels, hard rock TBM tunnels, drill & blast tunnels, road header tunnels along with tunnel lining systems. It will also review the performance of successful CSO systems that include design life cycle, vortex and drop shaft configurations, pump stations, storage and conveyance strategies and long term operation and maintenance criteria. HISTORY and BACKGROUND Prior to development of mandated wastewater treatment plants, collecting both wastewater and storm water runoff in a single-pipe system was an efficient and economical solution. The early combined sewer systems were typically designed and sized to carry several times the average dry weather wastewater flows and not designed to handle a mixed volume of waste water and storm water during a wet weather event. Beginning in the early 1970s, federal legislation (Clean Water Act of 1972, Clean Water Act of 1977 and the Water Quality Act of 1982) changed how municipalities and industries in the U.S. were required to treat and discharge wastewater into the nation’s surface waters. They were mandated to treat wastewater at federal regulatory standards for discharge into surface waters that is safe for humans, wildlife and aquatic life. The wastewater treatment facilities that evolved were initially designed and sized to treat only the peak volume of raw wastewater flowing during dry weather. Combined sewer system control sections or relief structures were installed upstream of wastewater treatment plants (WWTP) and were designed to protect WWTPs from potential damage that would be caused if peak volumes of raw wastewater mixed with storm water runoff reached and overwhelmed the WWTPs."

Jan 1, 2016