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By Floyd C. Bossard

In underground mining operations, the over- riding issue has to be protection of worker health and safety. The employees underground, making a living in a dangerous occupation, know these are major issues. These men bargain their lives and health on the presumption that the operating management knows its business, and they, the underground employees, can pursue their occupation with the assurance that management has provided a safe and healthy ambient underground environment. When management assumes the mantle of protection of underground workers, it has to be positive that qualified engineers have designed the project, and that capable operating personnel are in charge and always available. Those persons with these responsibilities must be knowledgeable in the engineering and occupational health aspects of sine ventilation. The ultimate function of a mine ventilation system is to provide a comfortable, healthy and safe ambient environment for the underground workers. The attainment of these objectives has been complicated with the increased application of electrical equipment and diesel-powered mechanized mining equipment underground (discharging toxic diesel emissions); increased production rates with the attendant increased production of airborne dust; and mine development in increasingly hostile mineral formations containing combustible strata gases, radon gas emissions, along with high heat and humidity. In general, the modern mechanization of present mining operations has resulted in a sore complex set of problems for the engineer planning the underground ambient environment.

Jan 1, 1983

By J. C. Yingling

[New stochastic process models are developed to calculate the probability of various fill levels in section feeders as a function of vehicle interarrival times, payloads and feeder-discharge rates. These models may be utilized to establish the minimum feeder-discharge rate necessary to prevent a feeder, with a particular surge storage capacity, from constraining the section's production rate. In addition, it is shown how the output from these models may also be utilized to calculate the probability of various flow rates at junctions in the conveyor haulage network, enabling one to size gathering belts. The model provides a basis for optimizing, (in economic terms) capacity specifications for feeders and conveyor belts in the materials-handling system by considering tradeoffs in the size of the two types of units.]

Jan 1, 1997

Recent accelerated exploration efforts in southwest China have progressively quantified the vast phosphate resources in the Yunnan Province. To date, according to Chinese geologists, potential reserves in the province may be on the order of 4 Gt, which would equal the entire US reserve base. Development of this vast reserve is underway at two sites located 60-70 km southwest of Kunming, the provincial capital of Yunnan. The first, the Kunyang open-pit phosphate mine, produces an estimated 1.5 Mt/a of 22-30% P20,5. The other project located north of Kunyang is the Haikou mine, which the Chinese consider a possible 2.0-Mt/a operation. Because average ore grades run 3% less than those of Kunyang, beneficiation will be necessary. While the latter project has been initiated on a small scale, it is basically still on the drawing board. Brown and Root and the US Bureau of Mines are assisting on the project. Both operations are under the direction a regional administration which reports to the Ministry of Chemical Industries in Beijing. Combined production from both mines could represent some 70% of China's future productive capacity. Ore reserves in the region are estimated at 400 Mt by local officials. Geology of the District The phosphates are considered Cambrian in age and rest on a Precambrian dolomite. The Indian Ocean, Chinese geologists say, may have been the original source. The line of deposition stretches on a trend from Vietnam in the southwest, through Yunnan, into Sichuan Province to the northeast. Because the area is considered very stable from a geologic viewpoint, large quantities of phosphate have been deposited and large outcrops are known to occur everywhere in the province, according to Chinese sources. The Kunyang and Haikou ore bodies are thought to be two wings of an anticline with the former the southern portion, and the latter the northern portion. Each ore body strikes on an east-west axis. While there are many localized phosphate operations throughout the province, the Kunyang mine is the premium producer. Kunyang's Mining Development The Kunyang open-pit mine was opened in 1966. During the early years, operations were considered somewhat disorganized. Systematic mine planning and normal operations were not initiated until just two years ago, according to mine management. In 1979, Kunyang finally reached its design capacity of 1.5 Mt/a. The ore body consists of two phosphate beds separated by a band of shale. The top layer of phosphate varies from 4 to 8 m, averaging 6 m. The middle shale layer is 2 in. The third layer, which is not as rich as the top, is approximately 4 m. To further complicate matters, the ore dips 15° to the south over a strike length that is currently undefined, but believed to be

Jan 3, 1980

By G. T. Adel, J. D. Miller, C. L. Lin

Washability analysis determines the maximum separation efficiency that can be achieved in the operation of coal preparation plants. Unfortunately, there are no on-line techniques for determining this most fundamental information. It now appears possible to determine coal washability on-line through the use of x-ray computed tomography (CT) analysis. This paper presents the results for the development of a CT-based, on-line coal washability analyzer. The development of appropriate hardware and software necessary to adapt a CT analyzer for use in determining coal washability is discussed. Testing of the analyzer using well-characterized coal samples is presented.

Jan 1, 2000

By K. Short

Today?s modern mining operations have literally dozens of applications and systems generating data whose information very often, are not crossed or centralized for operational decisions. In remote locations, the information and situation awareness is typically limited to the location itself. In addition, access to that information is limited to a small, select group of personnel that have received training on how to interpret the results. When the situation affects another area of the mine then information is relayed to the applicable areas involved. Few workers have time to analyze the situation thoroughly, to see how it affects the mines symbiotic relationship within all areas of production. If the capability to correlate and measure events and situations that affect your overall key performance indicators are not in place, the opportunity to identify process improvement becomes more difficult.

Feb 27, 2013

By R. G. McLusky

This paper analyzes the opinion in Bragg v. Robertson, 72 F.Supp. 2d 642 (S.D. W.Va. 1999), a case which threatens the future of surface mining in West Virginia and which will almost certainly result in new policies or rules that will affect surface mining everywhere. This paper addresses: (1) the jurisdictional bases of the action which relies on the federal surface mining laws to enforce a state mining program; (2) settlement agreements reached in the case that threaten to alter federal policies beyond West Virginia borders; (3) a programmatic environmental impact statement on mountaintop mining being undertaken by the federal government; and (4) an opinion by the Court outlawing excess spoil disposal in intermittent and perennial streams.

Jan 1, 2001

By Alan Zeni

Blind shaft drilling equipment has not changed substantially since the 1970s. Since it resides in a niche market between conventional shaft sinking and raise boring, the relatively small demand has resulted in some stagnation of development. In the 1990s the technology found a larger foothold in foundation and deep piling work for civil construction. WIRTH GmbH from Erkelenz, Germany has been servicing this market for many years with pile top drilling rigs and tools. Frontier-Kemper Constructors, Inc. recently entered into an agreement with WIRTH to develop a new generation of large diameter blind drilling equipment more specifically aimed at mining needs. The, recently completed, DHI-240 is the first rig to apply the most recent technology. This machine made its commercial debut in the fall of 2008. A description of the technology and a short case study of the first project will be described

By K. G. Kebkal, R. Bannasch

"Because the operation of tethered underwater vehicles in the deep ocean or under drifting ice areas is very complicated or impossible, the application of autonomous underwater vehicles (AUV) is preferred or even the only possible solution. However, this implies the possibility of a direct and real-time control over all AUV functions, which is only achievable with the availability of accurate positioning/navigation and a high-speed communication link. This paper presents a flexible bottom- or surface-based solution enabling high positioning accuracy of underwater objects (harvester, AUVs, bottom nodes); specifically, a multifunctional system that combines Ultra Short Baseline (USBL) transceivers and Long BaseLine (LBL) stations deployed at a large depth. Moreover, each baseline transponder is equipped with a high-speed communication device to provide the means for real-time AUV control based on the information about its current position, e.g. navigate it with direct commands and operating its actuators and other mechanisms. Moreover a communication link with a high data rate can provide valuable visual information from the operation area.Depending on how many nodes the LBL grid comprise has, target transponder positions can be estimated with an accuracy of several to tens of centimetres. The purpose of the paper is to present the experiments with all key elements of the multifunctional Hydro-Acoustic USBL-aided LBL Positioning and Communication System."

Sep 1, 2014

By Taehong Kim

An accurate and reliable prediction of Tunnel Boring Machine (TBM) performances, in terms of Rate of Penetration (ROP), utilization (U), and cutter wear rate, is a critical element in the successful planning and execution of mechanical tunneling project. Three open hard rock TBM projects were studied to establish possible trends and correlations between rock mass properties and machine performance. Based on this analysis and literature survey, three geological parameters, including RQD, RMR, and groundwater inflow rate, were identified as having the greatest impact on TBM utilization level. Rate of Penetration (ROP) and cutter wear rate were also correlated with fracture spacing, alpha angle, and Cerchar Abrasivity Index (CAI).

Jan 1, 2008

By J. D. Doll

MSHA has promulgated a rule to limit the exposure of underground metal/nonmetal miners to diesel particulate matter (DPM). In May 2008, the final personal exposure limit will be lowered to 160 µg/m3 total carbon. To comply with this rule, mine operators are implementing a variety of control technologies. In this study two types of control technologies (ventilation and cabs) which are being implemented in limestone mines were investigated. Two stone mines in this study use large diameter propeller fans for main mine ventilation and direct the air to the faces using auxiliary fans, stoppings, and long pillars while bypassing the old mine workings. NIOSH measured for sub-micrometer elemental carbon (EC) using SKC DPM cassettes (analyzed using NIOSH 5040) and a near real time instrument. With the present ventilation and the number and type of vehicles used, the concentration of EC from DPM at the working areas was at or below 400 µg/m3 for both mines and about 166 µg/m3 and 251 µg/m3 at the returns. The real time data showed that the ventilation was reaching the working areas and effectively diluting the DPM. Environmental cabs were also used to reduce DPM exposures in three underground limestone mines. Using NIOSH method 5040 and near real time EC instrumentation, NIOSH sampled inside and outside of a loader cab at one of these limestone mines to determine the effectiveness of the cab. The cab was found to be over 90% effective in removing DPM as long as the cab system was properly maintained, and doors and windows were closed.

Jan 1, 2009

By N. T. Rogers

An accepted statement of fact is that transportation next to agriculture is the second most important industry in the world. The transportation networks of the United States contributed immensely to the growth and prosperity of our nation. My objective is to make each and everyone here aware of the need for communication between geologists, mining engineers, purchasing agents and transportation managers. Only through a cooperative effort is it possible to reap the benefits of transportation in the industrial minerals field. Transportation is often thought of in terms of trucks, rail cars, barges, covered wagons or whatever. If this is your only exposure to the transportation industry then you probably spent most of your life in a cave.

Jan 1, 1989

By T. Hudaverdi

Several studies have been conducted on blastability and prediction of fragmentation. The term blastability is used to refer the susceptibility of the rock to blasting and is closely related to fragmentation. Parameters that determine fragmentation by blasting may be divided into two groups. The first group consists of blasting design parameters. The blast design parameters are controllable parameters and determined by the explosive engineers. The burden, spacing between holes, bench height, drillhole diameter, stemming height and explosive density are all design parameters. The second group consists of rock mass parameters that are referred to as uncontrollable parameters. The uncontrollable parameters are physical and mechanical properties of rock and rock mass structure. The strength, modulus of elasticity, density of rock, number of joint sets, joint orientation and joint spacing are among uncontrollable parameters. The rock mass parameters and blast design parameters should be considered together to explain fragmentation process. In this study, a blast database was accumulated to use for multivariate analysis. The blast database contains the blasts performed near Istanbul region quarries and the blasts that were preformed in various mines in the world by the blasting researchers. The cluster analysis was used to separate the blast data into different similarity groups. Group memberships were analyzed and checked by the discriminant analysis. Then, the multivariate regression analysis was used to develop a prediction equation for blast fragmentation for each group. Finally, a validation of the suggested models was performed for various mines. The model comprises blast design parameters, mechanical properties of rock and rock mass structure.

Jan 1, 2011

By R. Bauer

Adaptations and redesign of the existing already very successful and proven road milling machine concept and technical innovations such as an optimized, specifically for mining application developed cutting drum, cutting housing design and cutting tools, high manoeuvrability achieved via a tight turning radius, a three disk clutch system and a cutting drum drive that allows for the acceptance of higher loads, a complete reinforcement of the chassis to withstand higher vibrations and torque, the installation of increased engine power via a modern drive unit, a specifically for mining/construction applications developed operator’s platform and finally a redesigned air intake system and the adaptation of the levelling system resulted in far more cost effective and advantageous capabilities of Wirtgen Surface Miner in soft to medium hard mining and construction applications. As the achieved results show for the first time in modern surface mining history mechanized cutting is capable to compete successfully against traditional drill, blast/ripping and other conventional mining methods.

Jan 1, 2007

By Gregory D. Savage, Bruce M. Everett

Introduction The growing role of Colombia as a major supplier of internationally traded steam coal has been widely discussed in the industry. Although Colombian coal has been produced and exported in small quantities for a number of years, the country's position as a major coal exporter began in earnest in 1985 with the first commercial exports from the Cerrejon North Block Project. The mine is located on the Guajira peninsula in northeast Colombia, about 145 km (90 miles) from the coast (Fig. 1). In addition to the mine itself, the project involves construction of a dedicated railroad and port. This forms a modern, efficient, and integrated system. The project is embodied in a 50-50 association contract between International Colombia Resources (Intercor), a wholly-owned subsidiary of Exxon, and Carbocol, the Colombian state coal company. Intercor and Carbocol share investment and operating expenses equally. Intercor has the additional responsibility of managing operations on behalf of the partners. Each partner is entitled to 50% of the coal produced, and each markets its share separately. The project is a multi-seam, truck and shovel operation, based on large reserves (2 to 3 Gt or 2.2 to 3.3 billion st) of high quality bituminous coal. Exports began in the first quarter of 1985, at modest levels through what is called Early Coal Facilities. The permanent coal handling system began operation in February 1986. Production will increase rapidly in each of the next few years, reaching the design capacity of 15 Mt/a (16.5 million stpy) in 1989. Based on available resources, however, the resource will support expansion, and continued growth in production into the 1990s is feasible. Importance of transportation The success of a new coal export venture, such as Cerrejon, depends heavily on efficient transportation. In the international coal industry, overland and ocean transport can in some cases account for 40% to 50% of the final value of the product. Many coals, such as western US subbituminous coals, cannot reach export markets at all because of their low heat content and great distance from export markets. By the same token, low-grade resources are often commercially attractive for local markets even in the face of competition with much higher quality coals from distant sources. Figure 2 shows the growth in steam coal imports into Europe, the largest trading market. Through

Jan 6, 1986

Analysing a flotation plant?s operating performance requires accurate metallurgical sampling. Typically, the aims of performing flotation plant surveys are to establish a consistent and accurate understanding of the operation of the circuit as well as to identify potential areas for improvement. Once the data have been collected, a mass balance is required to provide a consistent set of data from which plant performance can be assessed. Mass balancing is a key skill that many metallurgists and mining industry professionals are familiar with. Mass balancing reconciles the feed and product streams throughout the plant and is sometimes used for accounting of the material entering and leaving a system (eg. JKMetAccount). However more common reasons for mass balancing are: better understanding of the flowrates within a system, assessing the quality of data obtained from sampling and surveys, and providing a key dataset for assessing and improving the performance of unit operations. Mass balancing requires practice and experience to determine if the results are reasonable. There are various software programs available to assist in the mass balancing and understanding of processing plants. This paper is focused on JKMultiBal initially developed by Gay (1993), and then later commercialized by JKTech. JKMultiBal in its current release is for balancing data in both one and two dimensions, i.e. balancing data on either sized or assay bases as well as size-by-assay. With the recent trend in flotation circuits becoming more complex, JKMultiBal has been used to gain a better understanding of the processes occurring within the circuit. This paper provides a description of the program as well as several case studies where the two-dimensional mass balancing has resulted in improvements in plant performance.

Jan 1, 2009

By Stig Eriksson

In Switzerland two major railway systems as shown below in Figure 1 has recently been completed or is under construction: ¦Lötschberg, south of Bern which was commissioned in 2007 ¦Gotthard, south of Zurich which is scheduled to be commissioned in 2016The aim is to increase the transport capacity of the railway system and to transfer more transport of goods to the railway by offering transport of trailers and lorries on the new railway systems. It will have a positive environmental impact but also improve the congested traffic situation of the highways in north-south directionThe Gotthard tunnel is totally 57 km (35 mile) long and the Lötschberg tunnel is 35 km (22 mile) long. Both tunnel systems consist of two parallel single track tunnels connected with cross tunnels at every 333 m (1 093 ft). Additionally there are cross-over tunnels and caverns for installations and operation. In the Lötschberg tunnel, the majority of the excavation has been by Drill & Blast and in Gotthard tunnel the major part is being excavated by TBM.

By J. G. Davis

The St. Peter Sandstone is typically a well-sorted, friable, ultra-pure, fine- to medium-grained, quartzose sandstone with silica content higher than 99 weight percent in places. The sand grains are well-rounded, highly spherical and characteristically frosted. Their size typically varies from 2 millimeters diameter (No. 10 U.S. Standard Sieve Series size) to less than 0.08 millimeters diameter (No. 200 U.S. Standard Sieve Series size). A freshly exposed surface of the formation is commonly white with shades of pink and green. Weathered surfaces are a dirty gray or brown and are case-hardened at many localities. Bedding is characteristically indistinct, and the formation usually appears massive throughout. The rock is cross-bedded and ripple-marked locally. The formation is generally porous, permeable and rarely fossiliferous in Missouri. The St. Peter is continuously present in the subsurface in the northern half of the state and along the southeastern edge of the state. The St. Peter crops out in a narrow band that starts in western Montgomery County and runs southeastward, along the Missouri River, to just west of St. Louis and continues south, just west of the Mississippi River, through Scott County. The outcrop belt varies from less than one mile wide to over ten miles wide, and it is over 150 miles in length. The formation dips into the subsurface radially away from the outcrop band. A notable isolated outcrop occurs in Lincoln County to the north of the main outcrop band. The St. Peter is discontinuously present in the subsurface along a band in the west-central portion of the state. It is not present at the surface or in subsurface in the remainder of the state. The formation averages 80?100 feet thick. There is an estimated 3.8 trillion short tons of St. Peter in Missouri. Sieve analyses on drill cuttings indicate three subsurface locations in northeastern Missouri where the St. Peter is greater than 10 percent by weight of sand falling in the 20?40 U.S. Standard Sieve Series size range. The St. Peter was first produced in Missouri in the 1870s for the manufacture of glass. Since that time it has been used as a paint additive, filler material, polishing compound, filtering media, and recently it is commonly used as a fracture proppant in oil and gas wells. The St. Peter is currently quarried and produced in Missouri from four sites located in St. Louis, Jefferson and Perry counties. In the same area there are at least nine abandoned historic mine sites.

Feb 27, 2013

By William D. Leech

Lebanon used a TBM for the firsttime to excavate a tunnel in the country. A main beam TBM, built in 1979, bored the 3.8 m (12.5-ft) diameter by 4,020 m (2.5-miles) Madiq Tunnel. The TBM bored through karstic terrain of dolomitic limestone, limestone and marly-limestone rock having near horizontal beds with more than twelve faults crossing the axis of the tunnel. The TBM also encountered more than six major karst features, filled with various combinations of boulders, clay, void space and water. The excavation through these collapsed-breccia zones drastically slowed the TBM?s progress. When complete, which the Madiq Tunnel is a part, the Kesrouane Water Project along the coast will bring fresh and irrigation waters to the parched and heavily populated region north of Beirut. The paper will describe the tunnel geologic features, karst genius, TBM upgrades and performance, and TBM/karst difficult situations

By D. W. Wu, M. T. Haque

A novel impedance probe has been commissioned specifically for capturing fast dynamic information about filtration processes. It provides an attractive alternative to more complex measurement techniques in situations where the slurry system is primarily one-dimensional. The probe can monitor mud-line, slurry densification and drainage. Dynamic variations in cake permeability are obtained by combining dynamic mud-line information obtained with the probe and filtrate rate data derived from a leaf test apparatus. The measurements are re-viewed in relation to micro structural measurements obtained on iron ore filter cakes. The practical significance of these measurements for optimization of the filtration process is discussed.

Jan 1, 2000

By Jozef F. Zurawski

Increasingly new interceptors or new Combined Sewer Overflow (CSO) projects require connections to existing tunnels. More often than not, the existing facilities are old, in poor or questionable conditions, without proper construction records or as-built drawings. Many cannot be easily inspected unless major construction effort provides flow by-pass for safe access. This paper provides general guidelines on how to approach the problem of assessing the condition of old tunnels, how to plan and design the connection with limited physical assessment, how to develop the scope of work for the bid documents and how to provide geotechnical guidelines and designs for the bid documents.

Jan 1, 2008