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By Christian Maguire

The presence of hydrogen sulphide in sewerage systems leads to severe concrete corrosion. Acid causes breakdown of the concrete matrix, and attacks reinforcement. Older sewer systems under acid attack are often found to be acutely corroded, sometimes after short operational periods. Consequently secondary liners are now almost always used. Polymer concrete is extremely acid resistant and if used in segmental linings can forgo the need for a secondary lining. Combined with fibers and/or GFRP rebar Polymer Concrete can produce a very strong acid resistant lining, saving considerable time in the installation of additional liners. This paper explains the problems and advantages of using Polymer concrete in segmentaly lined wastewater tunnels, addressing areas of design, cost, and programming.

Jan 1, 2008

By P. Rostami

It is important to study the ventilation system in order to better design and control of the working environment in deep underground mines. With increasing depth, heat, and humidity performance may be reduced and impair the attention of workers. The purpose of this paper is to apply a complex; development-end model configured in the MULTIFLUX program, developed at the University of Nevada, Reno, USA. The MULTIFLUX development-end model template has been benchmarked against measurement results from two UK coal mines in previous studies. The present study is a test of MULTIFLUX application in a metal mine. The model incorporates the simulation of the air flow field in the drift and the auxiliary air duct; simultaneous heat and humidity transport from the drift wall; heat and mass exchange between the air in the drift and the ducts; and the evaporation of process water and/or condensation of vapor as governed by the psychometric conditions. The results are compared with field data, measured at the Lucky Friday Mine (LF) in Idaho, USA, an underground mine and also shown between the results from the MULTIFLUX-based model, and those from another program, Kduct, developed at the Kyushu University in Japan.. Gao, K. Uchino & M. Inoue Fukuoka, Japan (2002)?

Jan 1, 2011

By D. E. Pollock

Recent NIOSH published information has shown an increase of rapidly progressive coal workers? pneumoconiosis (CWP) in the southern Appalachian coal region (SAR) of the U.S., despite the fact that compliance data indicates that most coal miners have been exposed to coal mine dust concentrations below the statutory limit of 2.0 mg/m³. While the exact cause of these elevated CWP levels in the SAR has not been established, several factors may be contributing to the increase in occupational lung disease among coal miners. The mining of high rank coal is known to lead to higher CWP rates, and this type of coal is mined in a portion of this region. Also, a high percentage of the mines in the region are on reduced dust standards because of the high silica content of the airborne dust resulting in miners possibly being exposed to excessive amounts of respirable silica dust. Exposure to excessive amounts of respirable silica dust can lead to silicosis, a disabling and potentially fatal lung disease. NIOSH's Respiratory Hazards Control Branch has been investigating the possible causes that would account for the observed higher trends in disease progression through literature review, data analysis, and in-mine surveying. The investigation to date has revealed that underground mines are faced with cutting large amounts of rock in order to maintain haulage clearances. Cutting rock not only increases the potential for silica exposure, it increases the requirement for machine maintenance which was a concern observed during dust surveys conducted by NIOSH. Over half of the mines operating in the SAR are on reduced standards due to high silica content. Adequate face ventilation of the continuous miner and roof bolter and limited down-wind operations from the miner are also issues of concern and items which require the constant attention of miners operating in these conditions. Disclaimer: Mention of any company or product does not constitute endorsement by the National Institute for Occupational Safety and Health.

Jan 1, 2009

By Jan L. Reichelderfer, Thomas L. Richardson

Completion of the H-3 Highway Tunnel Project was a critical element in opening this award winning project. The exploratory tunnel was completed as a maintenance tunnel and included difficult shafts extending into the main tunnel cross passages. The project also involved a major addition to the traffic operations center including a deep excavation in close proximity to the tunnel portal structures. The projects also included various completions and improvements to the main tunnels, such as paving, drainage, maintenance, and a variety of critical life-safety issues, such as radio systems, telephones, etc. The highway opened in December 1997.

Jan 1, 2001

By S. M. Carpenter

In response to the FY2008 Consolidated Appropriations Act (H.R. 2764; Public Law 110?161), the United States Environmental Protection Agency (USEPA) issued the final Mandatory Reporting of Greenhouse Gases Rule (MRR). The rule, signed by the USEPA Administrator, Lisa Jackson, on September 22, 2009, requires reporting of greenhouse gas (GHG) emissions from large sources and suppliers in the United States, and is intended to collect accurate and timely emissions data to inform future policy decisions. The MRR will go into effect on January 1, 2010, and a report of the total emissions for calendar year 2010 will be due to the USEPA by March 31, 2011. Under the final MRR, suppliers of fossil fuels or industrial greenhouse gases, manufacturers of vehicles and engines, and certain facilities that emit 25,000 metric tons or more per year of GHG emissions are required to submit annual reports to the USEPA. The gases covered by the rule are carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFC), perfluorocarbons (PFC), sulfur hexafluoride (SF6), and other fluorinated gases as outlined in Table A-1 of Subpart A of the MRR, which is also provided in Appendix A of this report.

Jan 1, 2011

By K. Tabra

In a mine operation, the proper strategy to handle residues is one of the main concerns, in particular when dealing with mine/plant liquid effluents. Most active water treatment systems at metal mines rely on standard alkali-addition procedures. However, the increase of mineral prices, stricter environmental standards and high metal content in some effluents, has led to the development of alternative treatment techniques for their removal and/or recovery. This article presents a roadmap to face mine wastewater treatment requirement, with focus on two active treatment strategies: 1) conventional lime-based technology and 2) the use of NaSH or Fe(OH)3 for metal precipitation and separation, including possible valuable elements recovery. The Roadmap consists of 1) Approach to effluent treatment 2) Characterization 3) Precipitation tests 4) Solid/liquid separation tests and 5) Economic analysis.

Feb 27, 2013

By D. W. Olson

Garnet has been used as a gemstone for centuries. However, garnet’s angular fractures, relatively high hardness and specific gravity, being chemically inert and non-toxic and free of crystalline silica, and its ability to be recycled make garnet ideal for many industrial applications. Garnet is the general name given to a group of

Jan 1, 2005

By Robert L. Hautala

In 1978, Congress established a series of mineral institutes for a limited time to assist financially in mineral industry education and research. Later, education and research were separated, establishing generic institutes for specialized research that transferred the former research budget from the base mineral institutes program. One of the generic institutes is the Mine Systems Design and Ground Control (MSDGC). It provides for research funding specifically for mining. Other parallel generic institutes were established in pyrometallurgy, comminution, waste management, etc. MSDGC was established at Virginia Polytechnic Institute and State University(VPI). The founding group included the University of Alabama, University of Kentucky, University of Nevada Reno, University of Idaho and University of Alaska reporting through VPI to the US Bureau of Mines (USBM) and Congress. Other universities also participated on an ad hoc basis.

Jan 1, 1996

By L. Lipsett

"Human rights can contribute to sustainability in the mining sector, both in theory and in practice. Both human rights and sustainability share a common concern to improve economic prosperity, environmental health and social equity by avoiding negative impacts and conflict, as well as by engaging with and empowering affected communities. Globally, there is an emerging consensus that companies have a responsibility to respect international human rights standards. Respecting human rights means that mining companies are responsible to ""do no harm"" to the people and communities affected by their operations. After a discussion of the Protect, Respect and Remedy framework for business and human rights, this paper illustrates some examples of how international standards for human rights and sustainability interacted in a recent assessment of Goldcorp's Marlin Mine in the Western Highlands of Guatemala. The final section explores how human rights should be integrated into broader policies and procedures for corporate sustainability. This includes integrating human rights into ESIA processes, legal compliance, corporate governance and grievance mechanisms. Pressures on mining companies to respect human rights will not disappear; therefore, a proactive and integrated approach to human rights is a fundamental component of a broader strategy for sustainability"

Jan 1, 2011

By Colin P. Pigott

The paper describes a variety of existing techniques and equipment which when combined together permit faster and cheaper drilling of shafts in soft to medium strength formations. Drilling fluid circulation, methods of hole stabilisation and bit design, including the advantages of flat bottomed and conical bits, shrouds and skirts, tungsten carbide, long tooth and disc cutters are considered. The principles of rock chip transportation and bottom hole cleaning are described together with a new and very efficient fluid circulation system which was invented by the author.

Jan 1, 1985

By Carrie Pourvahidi

The California High Speed Rail Authority (Authority) was created by the State of California through legislation in 1996. The purpose of the Authority is to plan, construct, finance and operate a statewide intercity high speed passenger rail system. In 2004 the Authority prepared a programmatic level environmental document in compliance with the California Environmental Quality and National Environmental Protection Acts (CEQA and NEPA).The Authority and Federal Railroad Administration (FRA) were the lead agencies overseeing the development of the environmental documentation. The resulting document includes two volumes and 64 supplemental technical reports analyzing the transportation needs for California and the selection of an approach to meeting the project transportation needs. The Programmatic Environmental Impact Report and Environmental Impact Statement (EIR/EIS) identified High Speed Rail as the most environ-mentally protective, sustainable and economical approach to meeting the state?s projected transportation needs.

Jan 1, 2008

By R. Owen, T. Canty, C. Marks

The industrial vision system provides on-line 2D particle size analysis for aggregate slurries in both the overflow and underflow of hydrocyclones. This paper covers required vision system features allowing CCD cameras to function in the harsh environment of a mine milling area. The study conducted demonstrates the system’s capacity to obtain particle size distributions for controlling hydrocyclonic separators. The particle size distribution is obtained within seconds and immediately updated to allow for process adjustments. Results are then provided as a graphical computer generated display or output as a 4-20mA current loop for process control. The primary use of the vision system is in classifying particles in cyclone overflows which are often a few microns in size. Typical size information for actual mine slurry samples are presented and possible control schemes discussed.

Jan 1, 2002

By G. H. Lewis, C. L. Krcil, N. S. Harding, D. E. Havekotte

Introduction Limestone injection work was completed in a 440-kW (1.5-million Btu per hour) pilot-scale combustor in preparation for a 50,000-kg/h (110,000-lb per hour) industrial steam boiler limestone injection test program. The main objectives were to: (1) identify the important variables that affect sulfur capture, (2) determine the maximum SO2 removal, and (3) determine the effect of limestone addition on furnace operability and heat transfer. A more detailed report is given by Lewis et al. (1985). The test program was divided into two phases. The objectives of Phase I were to determine the important variables that affect SO2 reduction and to investigate the effect of limestone addition on combustor operation and heat transfer surfaces. The objective of Phase II was to determine, using only the important variables identified during Phase I, the conditions that resulted in the greatest sulfur dioxide reduction. Phase I Test program Using one limestone, five variables were identified as having an effect on SO2 reduction. These are noted with their respective ranges: heat release rate [103 to 166 kW/m3 (10,000 to 16,000 Btu per hour-cu ft)], Ca/S molar ratio (0 to 3), flue gas oxygen concentration (3% to 5%), additive particle size [90% -150 µm (-100 mesh) and 90% -45 µm (-325 mesh)], and burner stoichiometry (SR = 0.75 and >1.15). A 2.3% sulfur northern West Virginia coal, pulverized to a nominal grind of 70% -75 µm (-200 mesh), was burned for the tests. The limestone used was obtained from a Maysville, KY, quarry and contained 51.75% (wt) CaO. An 11-run statistically designed program (plus three duplicates) was used to screen the five variables. The effect of limestone injection on the combustor heat transfer surfaces was determined by comparing the heat transfer rates through a slag panel and fouling probes during periods with and without limestone injection. Combustor operation was determined by noting any operating problems that occurred during the tests. Test procedure After furnace wall temperatures had stabilized at operating conditions, heat transfer surfaces (slag panel and fouling probes) and the convection section were blown clean, and a four-hour test was begun. The

Jan 12, 1986

By A. D. Nicholson

This paper presents an approach to quantitatively calculate the neutralization of acid by silicate minerals, based on the chemical kinetics of acid reacting with silicates. This approach incorporates incongruent dissolution mechanisms and the effects of silicate iron content on net acid consumption, and offers guidelines for considering the extent to which specific silicate minerals will react. This approach differs from previous methods of estimating silicate buffering: it is based more on the fundamental chemistry of acid generation, and less on potentially misleading empirical measurements of acid neutralization.

Jan 1, 2002

By G. A. Gamble

Fans used to ventilate subway, passenger rail and vehicular tunnels are similar to the fans used to ventilate underground mines. However, tunnel ventilation fan systems are typically designed to meet NFPA 130 or 502 standards, while mine ventilation fan systems must comply with the appropriate federal mine safety regulations. As a result, fan operation requirements and performance criteria, as well as typical fan and duct configurations differ significantly for tunnel and mine ventilation applications. Variations in environmental conditions in tunnels as compared to mines also result in differences in fan performance and material specifications. The need to enclose tunnel fans within building structures creates space restrictions impacting fan size selection that are not commonly encountered in mine fan installations, resulting in different approaches to selecting fans for the two types of tunnels. This paper discusses the various similarities and differences in design considerations for tunnel and mine ventilation fans.

Jan 1, 2009

By H. Lyn Bourne

This is the seventh annual tabulation of royalty information. It is also the first year in which some data have been deleted to make room for new data. The concept of royalties evolved from a time when the government owned all of the land, including mines, to the situation where free miners won the right to claim minerals but paid a portion of their production to the royal treasury. Today, a mineral royalty is a payment to the owner of the mineral rights for the privilege of producing the mineral commodity. However, some people incorrectly believe that the selling price and the royalty are the same thing. The contract between the owner (lessor) and the mining company (lessee) is the mineral lease. Some clauses that are common to mineral leases include: identification of property, granting clause, reservations, definitions, royalty rate, taxes and title, indemnity, termination, inspection, assignability, successors, and reclamation. There often are variations in royalty rates for a given commodity that reflect differences in location, quality, market conditions or public versus private ownership. History In the time of ancient Rome, the government owned the mining properties by virtue of conquest. It would lease the mines to favored citizens who would pay rent to the State. Various conditions of sovereign ownership of both land and mineral rights continued in Europe until the Renaissance. As the laws evolved for land ownership by private citizens, the concept that minerals belonged to the State (King, Crown, sovereign) continued until about the 15th century. Free miners challenged the notion of sovereign ownership and won the right to discover and claim minerals. But a portion of their production had to be paid to the sovereign - a royalty. So, the original concept of a mineral royalty was a tax on production that was due to the Crown or Church. The term mineral royalty, as it is known today, is a payment to the owner of the mineral rights (formerly the royal owner) for the privilege of mining and producing the mineral commodity. The owner of the mineral rights, the lessor, and the mine operator, the lessee, enter into an agreement to mine the property. The agreement is the lease. While this concept is common, there are some who do not understand that the royalty is a portion of production paid to the owner as agreed on in the lease document. This author has seen reports where the selling price of a commodity has been quoted as the royalty. ("They get 70 cents a ton royalty at their pit and the guy down the road only has a 65 cent royalty.") These reports have been authored by people not familiar with the mining industry. Lease clauses In addition to the amount to be paid the lessor, there are several other items to be addressed in the lease agreement. The following list may not be all inclusive, but briefly describes most of the common clauses any good mining lease should contain. Identification: This opening clause names the owner (lessor) and the operator (lessee), the address of each, and gives the legal description of the property. Granting clause: This part of the lease gives the time period or duration of the agreement and information about renewal periods. It also has language about the exclusive right of the lessee to mine the property. Reservations: If the owner wants to exclude any portion of the property or set some specific conditions about the operation, there needs to be a clause that describes these reservations. Definitions: This section should address some of the technical terms that the lessor may find confusing - short tons versus cubic yards, dollars versus percentage of average selling price, any escalator indices such as consumer price index or producer price index, and material mined versus material sold. Royalty: This section spells out what the royalty rate will be, how often it will be paid, if there is an annual minimum, the pay dates, and how the records will be kept. This section also describes the conditions under which the lessee is exempt from the annual minimum - natural disasters, strikes, governmental actions, or other causes referred to as force majeure. Taxes and title: The lease needs to identify who is responsible for the property taxes, severance taxes (if applicable), and other taxes that relate to the mining activity - taxes on equipment, improvements, or stockpiles. This is a good place in the lease for the owner to certify his ownership of the property and its mineral rights and also certify that no other leases are in effect. The lessees may want language that allows them to pay mortgages or other debts on the property to keep their lease in effect. Indemnity: This portion of the lease identifies that the lessee assumes the risks for lessee's mining operation. Lessor should expect indemnification by the lessee through standard insur¬ance policies - workers compensation, liability and property damage. Termination: Both the lessor and lessee want language that will allow them to terminate the lease. This section of the lease describes the conditions under which one of the parties may terminate the lease (failure of the

Jan 1, 1989

By D. I. Smith

Constructing tunnels in congested urban areas requires tunnels to be placed closer together and with less cover than was previously necessary. Contract CQ031 of New York?s East Side Access project will construct four six-meter diameter bored tunnels in a three-up one-down ?T? configuration, with less than three meters of soil between the tunnels. Mixed-face rock and glacial till conditions with a high ground water table will be encountered under active railroad yards. The tunnels will also pass beneath the busiest railroad interlocking in North America with cover as shallow as three meters. This paper discusses the challenges of designing segmentally lined tunnels for these conditions.

Jan 1, 2008

The occlusion of unliberated gold particles in silicates and sulfides in crushed/milled ore dictates the recovery that can be expected. The grade of this occluded gold in cyanide leach residues shows a consistent, general relationship to the head grade of the ore, irrespective of mineralogy or geographical location. The residue grade almost invariably increases with the head grade, but not in proportion to it. This phenomenon appears to stem from the nature of the geological events originally responsible for creating the ore deposits. A statistically-based technique for determining the true head grade-tail grade relationship from gold plant operating data is described. The effect is illustrated with results from several worldwide gold milling operations analyzed over the last 35 years.

Jan 1, 2008

By Minggao Qian, Jialin Xu, Wenqi Lai, Weibin Zhu

This article advances an innovative concept explaining the connotation and technical system of "green" mining. The important theoretical foundations of "green" mining are the distribution and development characteristics of joints, fractures and bed separations, and the seepage and flow behavior of methane and water in the broken rock strata following coal mining. The main focus of "green" mining technique includes water-preservation in mining areas, coal mining under buildings with bed separation spaces grouted to retard surface subsidence, partial extraction and backfill mining, simultaneous extraction of coal and coal-bed methane, coal roadway supporting and underground disposal of rock waste, underground coal gasification, etc.

Jan 1, 2005

By V. I. Lakshmanan, Dan A. Mackie

Traditional vat leaching methods have had limited success, primarily due to the high cost of loading and unloading the vats. In general, such batch methods are labor-intensive and costly. Heap leaching has emerged as a viable, low- cost alternative, but low recoveries, normally in the 70% range, offer opportunities for improvement. Also increased regulatory guidlelines for effluent and spent heap leach pads disposal offer potential for alternative methods. The Mackie Vat Leaching Jig (MVLJ) has had its incubation at Ortech International, where bench scale through pilot scale testing continues. Design developments and testwork over the past two years indicate that the time may be right for field trials.

Jan 1, 1990