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By C. Pomeroy, J. Weyer, J. Brune

"Mining began in the Erzgebirge (“ore mountains”) region of Saxony, Germany more than 800 years ago, and extensive underground workings cut through the entire area. Some of these old workings are still used today: not for production, but for offering an underground venue for research, tourism and university teaching. One example is the Reiche Zeche mine at the Technische Universität Bergakadamie Freiberg which hosts one of the oldest mining engineering programs in the world. It is imperative to keep all active mine workings well ventilated to make the mine safe for students, visitors and researchers. Since the mine workings at Reiche Zeche are so vast, extensive and, to a large extent unexplored and unmapped, it has been difficult to provide a complete, functioning and adequate mine ventilation model for this mine that accounts for all known and unknown leakage air flows. Researchers at the Colorado School of Mines have cooperation with their colleagues at Freiberg to establish a mine ventilation network model based on a limited number of air readings in known and accessible drifts. In order to balance the measured air quantities, leakage flows were quantified and mapped by comparing input and output flows of mapped drifts, and modelled using Ventsim Visual, a powerful visualization software package. The resulting mine ventilation model is used to locate and quantify the leakage air flows and to examine how much air is lost in each area. With this model, ventilation changes and improvements underground can be documented reflected in the model. This enables the Bergakadamie Freiberg to project air changes required for scientific experiments and to set up mine ventilation in specific areas and for specific needs. The model also enables better ventilation control and monitoring than before. Finally, the model can be used to predict ventilation changes and escape way contamination in case of a fire, ground fall or inundation in the mine. The latter becomes important as the lower mine workings are often flooded during spring runoff, which has created uncertainty about mine ventilation in the past. HISTORICAL BACKGROUND The discovery of silver, lead, zinc, tin and other valuable metal ores in the Erzgebirge region of Saxony, Germany began in the12th century and started a mining boom than lasted for centuries. Surface mines quickly developed underground to access the higher grade veins. Explored by the early geologists and driven by the ingenuity of the miners, the underground works expanded vastly throughout Freiberg and the surrounding region. Development followed the highest grade veins, and engineers developed solutions to drain water and provide limited ventilation to the underground workings. Still, engineered and planned ventilation was usually not a priority in the development of a new drift, which today makes ventilation modeling a significant challenge."

Jan 1, 2015

By J. Kulczycka

Poland in time of transition had been dealing with the remnants of the previous regime ? particularly in the field of environmental protection. The burden left was tremendous and there was a need for fast and effective tools for improving the environment. The idea of environmental protection had been supported by the introduction of a new environmental policy that underlined the importance of sustainable development in industry in the beginning of 1990s. This policy introduced high environmental fees and fines ? a concept not very popular in Europe in that time ? and good only for a country in transition to boost the protection of the environment. While this policy had its role to play, its role is now completed. It is time to move forward, especially when these environmental charges affect the international competitiveness of industries so much, and at the same time have virtually no influence on environmental protection investments any more.

Jan 1, 2005

By R. M. Clowes

Lithoprobe is a collaborative, multidisciplinary research project which is providing new insights into the tectonic evolution of the North American continent through its work within ten study areas across Canada. For the mining industry, such results provide a well-constrained regional framework and better understanding of tectonic processes which lead to the development of ore deposits. In mining camps, seismic reflection methods have proven effective in imaging shallow to moderately dipping litho logic contacts as well as structural features, and in some cases have been used for the direct detection of ore bodies. Here, short case histories are provided for the Abitibi greenstone belt (VMS deposits) in Quebec and the Thompson nickel belt in Manitoba.

Jan 1, 1999

By S. D. Thompson, L. Adler

J.R. Sturgul Thompson and Adler (1988) present a new simulator for use in designing conveyor belt systems for underground mines. Their model uses a large Fortran program to do a Monte Carlo simulation. Their approach is similar to that done by other researchers, such as Stanford (1965) and Newhart (1977). All Fortran based simulation models use an imaginary clock that is advanced a time increment. At each advance of time increment the program has to determine what is to take place in the system. Since many things can take place at different places in the system, this approach requires that a large amount of logic is needed at each step of the program. This, then, necessitates a great amount of jumping between different portions of the program. In fact, the Fortran program, CMBCS, takes up to 15 to 20 minutes to run on the mainframe and several hours for the PC. Such execution times are typical of Fortran based simulation studies. There have been other examples of Fortran based simulation studies in mining. Cross and Williamson (1969) presented a model of a working open-pit copper mine. Fosinato (1982) presented a model of the bucketwheel excavators for the large open-pit mines in Southern Victoria in Australia. These excavators discharge into a complex conveyor system, which can be thought of as being similar, but more complicated than the one modeled by CMBCS. All previous simulation studies using Fortran as the source code have several things in common: they all are very lengthy, often being of the order of 10,000 lines of code and take a great deal of CPU time to execute. The program of Fosinato takes more than 4.5 hours to run on a large mainframe. Also not mentioned by Thompson and Adler is the actual time it took to write the Fortran code. This, too, can be considerable, as Fosinato's program took several man years to write and de-bug. In order to change it, as the parameters change or as the mine increases, further large amount of time is needed. An alternate to such Fortran based programs is provided by using a special computer language known as General Purpose Simulation System (GPSS). This language is designed to solve a wide variety of discrete event simulation problems and appears to be particularly suited for mining situations as shown by Sturgul and Yi (1987). Although GPSS was introduced as far back as 1961, it has not been used in mining to any great extent. However, the original form was quite crude and inefficient compared to modern versions. Perhaps with the increasing popularity and availability of these recent versions, this will change. Two such versions are GPSS/H for the mainframe and GPSS/PC for the personal computer. GPSS/H allows for interactive usage, such as allowing input data to be entered via a menu. GPSS/PC has excellent graphical capabilities and one can actually view the simulation in progress. In addition, one can halt the simulation and change values of various parameters. If a particular portion of the simulation is in progress via a concept known as "microwindows." These new versions have greatly increased the potential for using the language for mining situations. Mining applications of GPSS have been given by Sturgul and Yi (1987), Sturgul and Harrison (1987), Sturgul (1987), and Sturgul and Singhal (1988). Schriber (1987) presents a summary of the recent advances in GPSS.

Jan 12, 1988

By R. M. Clowes

LITHOPROBE is a collaborative, multidisciplinary research project that is providing new insights into the tectonic evolution of the North American continent through its work within 10 study areas across Canada. For the mining industry, such results provide a well-constrained regional framework and better understanding of the tectonic processes that lead to the development of ore deposits. In mining camps, seismic-reflection methods have proven effective in imaging shallow to moderately dipping lithologic contacts as well as structural features and, in some cases, have been used for the direct detection of orebodies. Here, short case histories are provided for the Abitibi greenstone belt (VMS deposits) in Quebec and the Thompson nickel belt in Manitoba.

Jan 1, 2002

By C. Maltesh, P. Somasundaran

The ever increasing need for treating fine complex mineral bodies has led to the evolution and rapid development of advanced processing techniques for fine grinding, classification an if mineral separation and purification. With the introduction of these new technologies and understanding of underlying fundamental principles, mineral processing is now being applied to materials ranging from ceramics and composites to superconductors. In this review, current and potential applications of mineral engineering techniques to advanced materials processing are discussed. Particularly, material processing involving ultrafine grinding, dispersion and flocculation and thin film formation is examined. Novel techniques of solid/liquid separation involving manipulation of interfaces and use of high intensity high gradient superconductor magnetic equipment for solid/solid separation are discussed.

Jan 1, 1990

By Shuang Shuang Huang, John Fillos

Ozonation was evaluated as an alternative treatment process for leachates of municipal landfills. The study was carried out on leachate from the Fresh Kills Landfill, New York City. The leachate has strong tea color and BOD5 ranging between 90 mg/L and 130 mg/L. The average COD, TOC and NH3-N concentrations were 1800 mg/L , 550 mg/L, and 665 mg/L, respectively. The kinetics of the process were studied in a sparged batch reactor by developing concentration- time profiles for residual color and TOC. Continuous flow experiments were then carried out at two selected contact times. The process was found to be effective in the treatment of leachates for color and TOC removal.

Jan 1, 1992

By Paul Higley

Specialty Devices, Inc. and the CMRET/NIUST, University of Mississippi, have collaborated in the design and development of a new class of Robotic Underwater Vehicle (ROV) focusing on efficient, low cost, deepwater operations. The need for such a vehicle was driven by special requirements encountered in the establishment of the Gulf of Mexico Gas Hydrates Research Observatory at a depth of 850m in Mississippi Canyon Block 118 on a restricted budget. Requirements included deployment and recovery of tools and sensors and the connection of underwater-mateable electric and fiber optic connectors at depth. The standard complement of equipment required included; high-resolution video with lighting, scanning sonar, robotic arm, precision positionin and thrusters for limited transit and maneuvering. Conventional deep water ROVs are lowered in a large cage with a buoyant tether between the cage and the ROV. The tether is wound on a winch in the cage deployed as the ROV swims out from the cage. This cage is lowered on a large diameter umbilical cable with strength elements and communications elements and conductors for electric power. With increasing water depth the umbilical cable must become ever larger to accommodate increased power transmission loads and strength demands, with corresponding increase in deck handling equipment size and in turn, vessel size and overall cost. The surface ship must include a dynamic positioning (DP) system to control ship propulsion to maintain the position of the ROV cage at a position relative to the sea floor. DP ships with this capability and the ability to carry the large umbilical cable and winch are expensive.

Jan 1, 2008

By John H. Archibald, Arthur L. Miller, George A. Savanick

As part of its continuing research on selective mining, the Bureau of Mines has made progress toward developing a tool capable of remotely extracting hard minerals through a borehole. As the successor to the successful borehole miner, which extracted soft materials through a straight borehole, this new device has several innovative features: 1) it can propel itself in and out of an 8-inch borehole; 2) it can cut hard rock with an abrasive jet and transport the cuttings to the surface; and 3) it can negotiate deviated boreholes--the feature that enables it to follow a vein and extract only the values. This paper describes the development and feature testing of the reamer/miner.

Jan 1, 1991

By A. Iordanidis

Ieropigi Fe-Ni deposit is located in northern Greece, in Kastoria?s prefecture near Albania?s borders. A laterite profile exposed by opencast mining and placed near the basement of the mine was chosen for sampling. Ten samples, representing ?pure? Fe-Ni ore, ophiolite-bedrock, ?red? ophiolite and ?enriched? ophiolite were collected, based on macroscopic observation. The samples were analysed by X-Ray powder Diffraction (XRD) for the determination of the mineral phases. Iron and Nickel concentrations of the same samples were also determined by X-Ray Fluorescence (XRF) methodology. The Fe-Ni ore samples consists predomi-nantly of hematite, goethite, chrysotile (serpentine), saponite and quartz. ?Red? ophiolite samples consists mainly of chrysotile, hematite, quartz, calcite and small amounts of paragonite and goethite. Bedrock and ?enriched ophiolite samples are comprised of chrysotile, hematite, calcite, quartz, nontronite, paragonite and sepiolite. The Fe content ranges between 13% and 49% in Fe-Ni ore samples and between 7% and 10% in ophiolite samples. The Ni content ranges between 1% and 3% in Fe-Ni ore samples and between 0.3% and 4.5% in ophiolite samples (the higher content is observed in the so-called ?enriched? ophiolite). A correlation between Fe-Ni concentrations and mineral assemblages is being attempted in order to evaluate the nickel-rich mineral phases. It is shown that the nickeliferous minerals are serpentine, hematite, goethite and saponite.

Jan 1, 2006

By Lane White

The nature of the new Mining Law in Mexico, how it works and its implications for foreign investors were discussed from a variety of points of view by speakers participating in SME's special programming on Mining in Mexico at its An¬nual Meeting in Albuquerque, NM Feb. 14-17, 1994. Following are summaries of three papers whose primary objective was to give foreign investors some insight into the nature of doing business under the current Mexican Mining Law and its regulations. Lane White, Publisher.

Jan 1, 1994

By Ted T. Biddle

The world energy crisis has created a greatly expanded exploration program for energy fuels. The demand for materials required for drilling operations such as barite, which is the primary component of drilling fluids, has increased proportionally. As in the case of many other minerals, existing high grade barite mines are no longer capable of producing the required tonnage. Consequently, exploration and development of lower grade ore bodies has been increased. The need to produce a high quality product at maximum recovery rates, along with the ever changing economics affecting both selling price and production costs has triggered accelerated research programs toward more sophisticated and efficient beneficiation methods. Taking into account the specific gravity differential between barite (4.5) and the normal gangue minerals such as silica and calcite (2.7), gravity concentration methods are the prime consideration with flotation as a scavenging process. Greater emphasis on particle size liberation, size reduction and concentration is also indicated. In order to accomplish these objectives, it has been necessary to revert back to the old adage, "Recover your minerals as soon as they are free."

Jan 1, 1980

By Konstantinos Theodoridis, Michael Galetakis, Olga Kouridou

Recent advances in Artificial Neural Networks (ANN) and Adaptive Neuro-Fuzzy Inference Systems (ANFIS) have provided a new approach to the estimation of related quality characteristics, such as heating value, ash content and moisture of coals used for power generation. The basic strategy for developing ANN and ANFIS models for the prediction of missing quality values, is to train the models using an existing quality data set and an appropriate learning method. Statistical analysis results of the estimated values, showed that ANN and ANFIS are not only more accurate than the widely used regression models, but also tends to reproduce the variability of the initial data, while regression models generate a smooth representation of reality.

Jan 1, 2002

By S. D. Van Nort

Editor’s note: This is the first of two MINING ENGINEERING articles about the Grasberg deposit. The second, focusing on open pit mine development, will appear in the April issue of the magazine. The Grasberg porphyry copper-gold deposit of Freeport Indonesia Inc. lies within the Ertsberg Mineral District in central Irian Jaya, Indonesia. The Grasberg deposit was discovered during a drilling campaign initiated in the mid-1980s. Production at the open pit de- posit commenced in December 1989. The Grasberg copper-gold ore body is contained within a young igneous complex of dioritic composition that intrudes limestones of the Tertiary New Guinea Group. Alteration is typical of porphyry copper deposits worldwide except that higher grade primary chalcopyrite with significant gold values is associated with a centrally located zone of strong quartz stockwork. Irian Jaya comprises the western half of the island of New Guinea. The Ertsberg District lies 70 km (43 miles) inland from the Arafura Sea at an altitudeof3500 to45OOm (11,480to 14,764 ft). It straddles the Papuan fold belt. This belt forms the east-west trending chain of mountains that extend the entire length of New Guinea and is the site of numerous mineral districts.

Jan 1, 1991

By Dale R. Ralston, Roy E. Williams, Gerry V. Winter, George L. Bloomsburg

INTRODUCTION The majority of ground water flow models have been developed for large computer systems. Most of these operate under a batch mode of operation, that is, the data are input with a deck of punched cards. The advent of micro- and minicomputers over the last few years opens the possibility of adapting many of these large flow programs to the smaller computers. In general, this adaptation will require more computer time to run the program, but in many cases if the small computer is in-house, the overall cost may be less than that required for a large computer. There are also a number of peripheral devices that can be used to make the data input much easier. As an example, the use of a digitizer with a finite element or finite difference mesh reduces the data input time considerably; the use of a graphics terminal for display of the mesh immediately after it is developed shows immediately whether there are errors in the location of node points. DEVELOPMENT OF AN INTERACTIVE SYSTEM The finite element program, UNSAT2, has been used over the past several years by the authors for several ground water flow problems (Bloomsburg, 1977; Bloomsburg and Wells, 1978; Zahl and Bloomsburg, 1980). In the past these programs have been run on an IBM 370/ 145 computer under the batch mode of operation. One difficulty that has been encountered has been in determining the length of time step that must be specified for operation of the program. The problem is that if the time steps are too large, the program becomes un- stable and operation ceases. If this happens in the middle of the problem, the only alternative is to reduce the length of time step and repeat the entire run. This problem has been alleviated in other pro- grams by using a subroutine that determines the time step automatically. If the solution becomes unstable, the time step is reduced automatically and that portion of the solution is repeated. With an interactive system this can be done by storing the output pressures and restarting the program with the new output pressures. Under the batch mode of operation, there is an option in UNSAT2 that allows restarting of the program from the last point of solution, but this must be specified when originally starting the program. The interactive computer system that we use currently consists of a PDP 1 1 /23 with hard disk drive, CRT terminal, plotter, graphics terminal, digitizer, and printer. The computer has 256 K bytes of core storage and the hard disk drive will accept a 5.2 M byte disk. To run a large program on a computer such as this, some overlaying must occur; that is, subroutines are stored on disk and put into core storage only when they are actually needed for running the program. UNSAT2 required very few changes to run on this computer but some changes were necessary to take advantage of the interactive capabilities of the system. One of these changes consists of the development of a program called DBUILD to build the data file for running the program. This program calls for each piece of data by prompt statement and gives instructions for using the digitizer. The data are then entered in completely unformated form. The node points must be entered in order and the coordinates are determined automatically by the digitizer. The pressure readings or initial conditions on each node point are entered through the terminal. All element information also is entered through the terminal. After DBUILD is run the mesh may be displayed immediately on the graphics scope whereupon any error in node point

Jan 1, 1986

By Donald D. Haas

Contract mining has a definite place in the mining industry, both in the United States and around the world. A mine owner should evaluate the utilization of contract mining in the devel­opment and production of mining properties. This evaluation of contract mining should be performed at various times in the life of a mining prope1iy from the development and initial operation of a new mining project, periodically throughout the mine's life, and at mine closure. Many factors must be considered in ana­lyzing and evaluating the potential of contract mining and those factors are both quantitative and qualitative. Quantitative factors are those factors for which costs or measures can be determined or estimated objectively; and qualitative factors are those factors for which costs or measures must be determined subjectively and do not lend themselves to objective determination or estimation. Some of the qualitative aspects may provide only yes, maybe, or no answers while others will provide a tendency or partiality toward one answer or the other without a quantified cost. The major quantitative aspects include operating and capital costs, monitoring costs, capital preservation, acquisition and disposal of new and used equipment, direct payroll and administrative costs, recruiting and training costs, and employment and termi­nation of staff and hourly personnel. The major qualitative areas include corporate philosophy, risks associated with capital and operating costs, financing the project, operating control, operat­ing flexibility, recruiting and training of personnel, employment and termination, administrative concerns, and owner/contractor relationship.

Jan 1, 1998

By E. Topuz, Xing Wu

INTRODUCTION The air flow in the mine ventilation network can be categorized in three ways: natural splitting, controlled splitting, and semi-controlled splitting. In natural splitting, the air flow in branches of a ventilation network apportions itself according to the aerodynamic resistance of the branches. In controlled splitting, a prescribed quantity of air is circulated through each branch. In semi-controlled splitting, flow in some branches is fixed to a desired quantity while in other branches it is split naturally. In practice, the mine ventilation networks present the latter two situations. Usually, the resistance of each branch in the network is known and the quantity of air in the working place is predetermined by safety considerations. If the number of branches whose airflow quantities are known is equal to or larger than the number of the fundamental meshes in the network, then the network becomes a controlled splitting network (Wang, 1982 a). Otherwise, it is a semi-controlled splitting network. If no booster fans are used in the network, the problem can be solved as either controlled or semi-controlled splitting networks in order to determine the main fan pressure and regulator size and location. All techniques are based on Kirchoff's flow and energy conservation laws and Atkinson's Equation. Booster fans can be used in controlled and semi-controlled splitting networks. It has been proven both theoretically and practically that using booster fans in these ventilation systems can improve flow distribution and reduce consumption of power (McPherson et al., 1985). The current techniques used in determination of booster fan location and size include simulation, linear programming, CPM and cutset operation, out-of-kilter, and critical-path crashing. These techniques can be classified into two groups. The first group, including linear programming, CPM and cutset operation, out-of-kilter, and critical-path crashing techniques, deals with controlled flow networks. The second, simulation, can be applied to the handling of semi-controlled flow networks. Mathematically, the problem of controlled splitting networks can be solved more easily than that of semi-controlled splitting networks. This is because the controlled flow network can be formulated as a linear programming problem, for the solution of which there are several sophisticated algorithms. Moreover, the semi-controlled flow network is usually modeled through nonlinear programming, for which there are no universally applicable solutions. The procedure described by Wu and Topuz, 1986, can be used to convert a semi-controlled network to a controlled flow network, and the problem can then be easily solved by the techniques used for solution of a controlled flow network problem. In practice, a mine ventilation network may change from controlled splitting to semicontrolled splitting with advancement of mining. This dynamic nature of mine ventilation makes the problem more complicated and necessitates development of new solution procedures which will consider the overall economics of the system. CONTROLLED SPLITTING NETWORK The problem in controlled splitting networks with booster fans is to determine the operational characteristic of the main fans, and the location and size of booster fans and regulators. The objective is to satisfy the air flow rate requirement for each branch while minimizing consumption of energy. The techniques used for the controlled splitting network problem include linear programming, CPM and cutset operation, out-of-kilter, and critical-path crashing. The objective function and constraints can be expressed as follows (Wang and Pana, 1971): [ ]

Jan 1, 1989

By D. F. Doerr, E. Blalock, D. R. Bush, K. D. Cohen

"INTRODUCTION The design, development, fabrication, and test of cryogenic breathing apparatus is part of a much larger effort funded by the National Institute for Occupational Safety and Health (NIOSH) and managed through a Space Act Agreement with the National Aeronautics and Space Administration (NASA) at the Kennedy Space Center (KSC) in Florida. This effort is designed to create cryogenically based life support equipment that is responsive to the needs of miners as required by the Miner Act of 2006. Our goal was to design and build a liquid air based self-contained breathing apparatus (SCBA) that lasted 2 hours and would be used for the egress of miners during a mining accident and be refillable while worn. Therefore, the current report describes tests of an Advanced Cryogenic Breathing Apparatus (termed the ACryoBA) designed to provide miners egressing an emergency situation with a two-hour open-circuit SCBA. The ACryoBA utilizes low pressure cryogenic liquid air instead of high pressure compressed air commonly used in most commercially available SCBA. The ACryoBA can also be self-filled from strategically placed Cryogenic Air Supply and Fill Stations (CryoASFS) initially, and thereafter on the egress route approximately every 1 hour and 30 minutes with a 30 minute air reserve. The ACryoBA evolved originally from a one hour Liquid Air Pack (LAP) developed in the 1980’s for Space Shuttle Rescue forces allowing for longer duration and cool air (Figure 1). It was used successfully for many years, through the end of the Space Shuttle Program. The first attempt at a mine egress pack was the Cryogenic Breathing Apparatus (Figure 2). It was to have a low profile, two hours of breathing, attitude independence, and a simple rapid refill while in use. The CryoBA met the two hour criteria, but with difficulty due to excessive heat leakage caused by the dual 4 liter Dewar design. Much of the stored air was lost as it vaporized faster than it could be used. However, the pack was successful in demonstrating both attitude independence and a simple rapid refill capability. The ACryoBA project was designed to continue the progression and address the deficiencies in the CryoBA. The ACryoBA pack was designed to last 2 hours. It minimizes the heat leakage with a single Dewar and thereby requires less liquid air. The single Dewar design also minimizes weight, making it much more manageable by the user (Figure 3). The ACryoBA complies with 42 CFR part 84 NIOSH certification test requirements. One critical requirement for the ACryoBA is operation in positions other than vertical for periods up to 1/4 (i.e. 30 minutes) of the rated service life of 2 hours; this was accomplished by use of new technology called the “attitude independent pickup” which is abbreviated “AIP.” The AIP, developed by BCS Life Support LLC (patent #8,899,226), has a tube going from the top flange down through the center of the Dewar. At the end it has a flexible bellows and a weighted end. Due to the flexible nature of the bellows, the pickup at the end is free to rotate and follow the liquid level around within +/- 90o of vertical."

Jan 1, 2016

By Art Hamid, Manfred Wong, Carlos Jaramillo, Greg Raines, John Caulfield

"The Central Bayside System Improvement Project (CBSIP) is a critical element of the Sewer System Im-provement Program (SSIP), a 20-year, $6.9-billion investment by the San Francisco Public Utilities Commis-sion (SFPUC) to upgrade San Francisco’s 100+ years old seismically vulnerable combined sewer system. The CBSIP’s centerpiece, a proposed 10,000-foot-long (3,048-meter-long) Channel Tunnel, will provide reliable and redundant gravity conveyance and storage of combined wastewater flows from the northern and central parts of San Francisco to the Southeast Water Pollution Control Plant (SEP) while ensuring compliance with regulatory requirements for combined sewer discharges to the Bay. A tunnel with a diameter of 23 to 30 feet (7 to 9 meter) is being planned using pressurized-face tunnel boring machine technology. Project challenges include tunneling through Franciscan Bedrock, mixed ground conditions in close proximity to the Bay, connector tunnels and shafts, construction in congested urban environment, and challenging real estate issues for shaft access. BACKGROUND AND NEED FOR TUNNEL The City of San Francisco is one of the most beautiful cities in the world. About 850,000 people live in the city and many more come to work, for tourism, and for attending conferences. The SFPUC is a department of the City and County of San Francisco that provides energy, drinking water and wastewater services to San Francisco, wholesale water to three Bay Area counties, and green hydro-electrical and solar power to San Francisco municipal departments. The SFPUC wastewater system includes tunnels, large storage/transport boxes, 1000 miles of collection sewers, 28 pump stations, and three wastewater treatment plants. San Francisco’s combined sewer system collects both wastewater and stormwater in the same sewers, which is then pumped, treated to stringent state standards and discharged into the San Francisco Bay and Pacific Ocean. After decades of service, much of the sewer system is nearing end of its working life. During the 1989 Loma Prieta earthquake, damage to SFPUC water and wastewater infrastructure was extensive. The 11,200-foot-long (3,400-meter-long), 66-inch-diameter (1,676-mm-diameter) Channel Force Main, built in 1976, and a critical component of the SF wastewater system was also damaged. This force main carries 70 percent of the bayside dry weather sewage flow from the northern and central part of the city to the SEP. The force main is at the end of its life and was not constructed to the current seismic code; in addition it has no redundancy. Figure 1 shows the project background and the force main that will be provided redundancy by the new gravity tunnel."

Jan 1, 2016

By Don Fisher, Jean Juilland

Introduction A section of the Federal Land Policy and Management Act of 1976 specifies the procedure for areas the US Bureau of Land Management manages that have wilderness qualities. In part, FLPMA specifies that within 15 years of its approval, the Secretary of the Interior shall review roadless areas of 20 km2 (5,000 acres) or more and roadless islands of public lands identified during the inventory as having wilderness characteristics described in the Wilderness Act of 1964. Further, the Secretary shall report to the President his recommendation as to the suitability of each area or island for preservation as wilderness. However, before any recommendations for, wilderness designation, mineral surveys shall be conducted by the US Geological Survey and the US Bureau of Mines to determine if any mineral values are present. And finally, a Presidential recommendation for wilderness designation becomes effective only if so provided by an Act of Congress. BLM Inventory Procedures To fulfill these legal requirements, BLM is inventorying the land it manages for wilderness qualities. Since the law sets special provisions for Alaska, BLM included in its inventory only the public lands it manages in the conterminous US. In 1980, after public input, BLM picked 967 areas to be considered as Wilderness Study Areas. All of the selected WSAs are in 11 western states and the areas total about 97,128 km2 (24 million acres). From these 967 areas, through its multiple-use planning system, BLM is making initial recommendations of areas to be considered suitable for preservation as wilderness. Those WSAs that BLM initially considers suitable for wilderness preservation will have mineral surveys conducted by the USGS and the USBM, to determine mineral values. Based on these mineral surveys and other resources information including wilderness qualities, the Interior Secretary will report to the President his recommendations on the WSAs suitable for wilderness preservation. To make the initial recommendation of suitability, BLM managers will need information about geology, energy, and mineral (GEM) resources as well as information about other resources. BLM has begun a GEM assessment program to provide its managers with that information. This program is designed to provide information for a WSA suitability decision process that aims to supply minimum necessary GEM information. In essence, the program will provide preliminary assessment of the mineral potential for each WSA. Assessing the WSAs To accomplish this, a two-phase program was designed. In phase one, only existing data are collected and used. In phase two, new data are generated and added to existing data. Phase two begins only if BLM geologists, mining engineers, or managers consider the information provided in phase one as inadequate. This avoids unnecessary work and expenses and allows the program to proceed without undue delay. Figure 1 shows the two-phase process, including BLM's GEM in-

Jan 10, 1983