Search Documents

By A. L. Stomberg

Federal and State surface coal mining regulations require special handling of prime soil materials which result in additional costs, and no actual benefit when prime and non-prime soils are similar. The Coteau Properties Company proposes to mix both prime and non-prime topsoil and subsoils at the Freedom Mine in Mercer County, North Dakota, based on an analysis of soil physical and chemical characteristics which show these materials to be comparable.

Jan 1, 1985

By Jon Y. Kaneshiro, John S. Griffith, Anthony F. Stirbys, Mauricio Andrade

This paper presents an overview of the New Mississippi Tunnel Outfall for the Transportation Expansion Project (T-REX). The Outfall conveys highway and other urban drainage to the South Platte River as well as provides long needed relief from flooding problems in the southeastern portion of the Interstate 25 highway corridor. The Outfall tunnel incorporates a one-pass precast concrete segmented liner to convey storm water under I-25 then under Mississippi Avenue to the river. The Outfall crosses both the existing I-25 as well as the future improvements including under the Light Rail Transit, a new bridge abutment, widened lanes, and new retaining walls. The Outfall also crosses adjacent to several buildings and five bridges, under major traffic and utility intersections, and through difficult geology.

Jan 1, 2003

By John B. Jones

New concepts in shaft kiln processing are included in the design of two large diameter shaft kiln plants now under construction. One kiln will be used to produce cement clinker at the Boettcher plant of the Ideal Cement Company at Fort Collins, Colorado. The other kiln is for the semi-commercial oil shale plant for Petrobras, the Brazil National Oil Company at Sao Mateus do Sul, Parana, Brazil. Investigations on application of the new concepts are proceeding in a portable pilot kiln. The shaft kiln has long been recognized as a method of gas-solids contacting having the following principle advantages: l. High thermal efficiency 2. Ability to handle a variety of feed materials with a wide range of particle sizes 3. Minimum investment and operating cost

Jan 1, 1963

By Karel Rössler, Petr Vítek

"The Ejpovice tunnels in Czech Republic were built by EPBM in soft Clyashale, and in weathered profile with low soil overburden. The segmented liner at the cross-passage openings required support, which would not interfere with the EPBM clearance envelope during the scheduled pull back of the EPBM through both tunnel tubes. For that reason support frames or radial bolting could not be used. Steel rods inserted into the neighboring segments during the ring assembly, and later grouted were tested and realized as an innovative solution. The paper presents practical experience gained with the segmented liner support during cross-passages construction. INTRODUCTION An innovative solution using the grouted dowels was developed and realized for sixteen cross-passage openings of the twin Ejpovice Tunnels, whose construction was part of the railway track Rokycany – Plzen modernization. The following paper described practical experience gained with the innovative support of cross-passage openings, which was realized by short steel dowels grouted within the segments of the EPBM segmented liner. The paper is a continuation of the paper published in WTC 2015, which described the design aspects of the grouted dowels support, while the following paper concentrated on the production, and the performance of the dowel support observed during the breakout for the cross-passages openings. The connection by grouted dowels was patented by Metrostav, a.s. Company THE EJPOVICE TUNNELS CONSTRUCTION The Ejpovice tunnels construction started in 2013. The start of the high speed train operation through the tunnels was planned for 2018. The project was funded by the state government with the support of European Union funds of up to 70%.The tunnels were excavated with one EPBM (Earth Pressure Balanced Machine) with the external diameter of 9.89 m. The segmental liner inner diameter was 8.7 m, and thickness of 0.4 m. First, the South tunnel tube was excavated from the East portal, then the EPBM was pulled back through the South tunnel, and the excavation was started from the same portal for the North tube. After the South tube was freed from the EPBM excavation operations the cross-passage construction started. Due to the short time schedule, in the North tube the cross-passage construction started while the tunnel was still under construction. Therefore, the cross-passage construction was performed concurrently with the segments transportation, and with the EPBM pull-back through the tunnel. There were 8 cross-passages along the tunnels with a maximum distance of about 500 m, Fig.1."

Jan 1, 2016

By Bart Hogeweg

The development of deep sea mineral deposits creates a new horizon for the mining industry. In a field where mining technology meets deep-water offshore engineering, new challenges are faced to come to the successful exploitation of these deposits. With the absence of proven technology for the mining of these minerals, a ?technological green field? is entered. IHC Merwede (IHC), a global market leader in the dredging and wet mining industry, is on the frontline of these developments. MTI Holland, IHC Merwede?s research and development company, has undertaken a number research efforts focused on the successful development of technology for the mining of deep sea minerals. This paper highlights a number of these efforts and illustrates IHC?s continued dedication for the research and development of technology to enable the commercial mining of deep sea minerals.

Jan 1, 2008

By Brock H. Morrison

One of the major criterion of any mechanised tunnelling operation is to minimize downtime of the tunnelling machine by employing the most efficient muck handling system space and economic factors permit. A tunnelling machine which remains idle during a large percentage of the available shift working time is a luxury no contractor can afford. There are several possible reasons for non-productivity of a tunnelling machine ... the inability of the muck handling system to keep pace with the tunnelling machine on a continuous basis is one major cause. In large diameter tunnels, where several trains or more than one muck hauling unit can operate simultaneously, downtime of the tunnelling machine may be kept to an acceptable level. On small to medium diameter tunnels, 8 feet to 14 feet in diameter, the muck removal support system is normally restricted in capacity, resulting in an excessive tunnelling machine downtime as the tunnel extends from the shaft. There is a need for an efficient, continuous and economical muck removal system for small to medium size tunnels being driven by a hard rock machine. This paper is intended to provide an insite into pneumatic conveying, and explain the Radmark System; its development and utilisation in the tunnelling and mining fields. STATE OF THE ART Pneumatic conveying is the transportation of bulk materials

Jan 1, 1997

By R. L. De G. Solms

INDEX 1. INTRODUCTION 2. FLOODING 3. THE PLUG 4. THE FIRST ATTEMPT 5. THE SECOND ATTEMPT 6. PUMPING 7. TIGHTENING OF THE PLUG 8. SHAFT REPAIRS 9. POST-MORTEM 10. CONCLUSION

Jan 1, 1987

By E. Berrezueta

Automatic digital phase imaging should yield unbiased and representative characterizations of gold ores. However, this is not a simple tusk due to low gold grade, fine grain size, possible complex mineralogy, nugget effect, etc. Using the same sections of a gold-rich ore, a critical test was performed using an optical microscope (OM) and an electron microscope (EM). In general, the two methods are consistent and useful for ore processing. There are some minor differences, such as the detection of very fine gold grains is enhanced by EM. Key words: Digital imaging, Gold ores, Mineralogy, Electron microscopy, Optical microscopy

Jan 1, 2003

By Philippe Dumont

Presentation of the project Underground civil works to be performed They include two single track running tunnels and a service tunnel of a length of fifty kilometers . Many cross adits (180 adits) : to link the tunnels (53 cross passages), to relieve air super pressure from one tunnel to the other (87 piston ducts), to install technical adits (40 electrical rooms). Two cross-overs located at one third of the whole length, allow trains to shunt from one tunnel to the other so as to ensure one way traffic in case of emergency. Pumping stations allow water to be collected at the lowest point and pumped out. 1 Main features of the tunnels 1.1 The service tunnel This 4.8 m inner diameter gallery allows During civil works - front probing operations of the geological layers encountered (front and vertical probes). - lateral soil grouting that may be necessary to facilitate the boring of the two running tunnels . During operations - Maintenance and safety vehicles traffic - Fresh air supply to running tunnels - Fire protection and drainage system - Electricity supply and control and communication. The service tunnel has been bored with a 5.72 meter external diameter Robbins TBM for the undersea section, and a MITSUBISHI TBM for the land section.

Jan 1, 1991

By G. P. Dvoichenkova, E. A. Trofimova, M. V. Zaskevich, V. A. Chanturiya

The paper presents theoretical and practical aspects of directed adjustment of physicochemical properties (pH,Eh) and ion composition of recycle and mine water by electrochemical treatment. Treatment is run in the conditioners of diaphragm-type with production of alkaline catholyte of pH value up to 12 and acidic anolyte of pH up to 2. In process of water electrolysis the directed motion of Mg2+ and Ca2+ ions is observed from anode volume to cathode one, were they precipitate as hydroxides and carbonates; it leads to decrease of salt content in anolyte and catholyte. The anolyte has been concentrating anions, it is being saturated with oxygen, which reaches 20-35 mg/L. The results of experimental and industrial testing of electrochemical technique for mine and recycle water in flotation of diamond-containing and sulphide-scheelite, hematite, phosporite, apatite-nephelite, bauxite ores indicated the increase of recovery up to 2-1 5% and grade up to 0,5-2%, concurrent with decrease of reagent consumption from 15 to 50 %. Modules of industrial conditioners of different type capacity have been developed.

Jan 1, 1995

By Ed Van Eeckhout

The rockburst monitoring system at the Sunshine Mine has recently been improved to increase the certainty of burst locations and to output location results in a manner amenable to easy interpretation. Three methods of location calculation were used: a computer code provided with the hardware in-place (the MP-2501, a code based on the least-squares method (Blake et a1, 19741, and a nonlinear iterative code written by the principal author. The more accurate locations are given by the latter two codes, but still are only correct to within about 100 ft. This error is due to uncertainties introduced by the geologic and mining variations versus the assumptions made in the location codes. Software was then written to make two-dimensional plots of burst location by level, so management could monitor problems easily.

Jan 1, 1986

By John M. Marek, David E. Nicholas

INTRODUCTION The purpose of this article is to outline the data requirements for selecting a proper underground mining method and to discuss the general steps taken in selecting that method. Determining the appropriate mining method is an iterative process that continues throughout the life of a mineral deposit. We will discuss the subject from the standpoint of a feasibility study, where a realistic assessment is necessary in order to determine investment merit. The feasibility stage of a project is that point where the drilling program has defined sufficient geologic reserves to consider mining the deposit but little or no underground development has been done. Primary parameters for consideration in choosing a mining method are 1) geometry of the deposit; 2) distribution of grade; 3) rock mass strength for the deposit, as well as the hanging wall and footwall; 4) mining cost and capitalization requirements; 5) mining rate; 6) type and availability of labor; 7) environmental considerations; and 8) other site-specific conditions. Of these parameters, the first four have the most impact on determining the general mining method to be employed.

Jan 1, 1981

By Jeramy B. Decker, Paul H. Madsen

"During the excavation of the north bound tunnel of the Devil’s Slide Tunnel project, deformation (convergence) was measured after passing through Fault Zone B. The tunnel convergence was not symmetrical, but was larger on the left side of the profile. It was determined that a shear zone nearly parallel with the tunnel drive was contributing to the uneven deformation. This paper will discuss how it was determined that the shear zone existed and how multi-point borehole Extensometers (MPBX) were used to verify that a significant amount of the deformation was occurring due to movement along the shear zone as the excavation was advanced. In addition, performance of the shotcrete liner in the area of the convergence will be examined. Finally, the paper will consider the means and methods that were utilized to ultimately control and stabilize the deformation. INTRODUCTION The Devil’s Slide Tunnel Project consisted of excavating two 1,250 meter tunnels each with a profile of 80 m2 utilizing the New Austrian Tunneling Method (NATM) or otherwise known as the Sequential Excavation Method (SEM). The tunnels are part of the California Coastal Highway south of Pacifica, CA, a suburb of San Francisco. The tunnels were opened to traffic in March of 2013. Geological Setting The tunnels run north-south through the San Pedro Mountain ridge, which is part of the Santa Cruz Mountains. The tunnel lies within the San Andreas Fault system and is 7.2 km west of the surface trace of the San Andreas Fault and 2.8 km east of the surface trace of the San Gregorio Fault. The 10 km strip between these two faults is referred to as the La Honda structural and terrain block (Decker et al. 2010; Amini et al. 2005; Earth Mechanics Inc. 2003). Locally, the tunnel passes through three blocks representing different geological conditions: South Block, Central Block, and North Block (Figure 1) (Decker et al. 2010; HNTB Corporation et al. 2005). The South Block consists of Mesozoic aged granodiorite and quartz diorite. The South Block also contains many local shear zones and a low angle thrust fault (Fault A). The South Block ends at Fault B, which is the southern border of the Central Block."

Jan 1, 2016

By William R. Taylor

The information I have concerning the early in situ uranium mining activities in Texas is "sketchy." Apparently, the first test was conducted between 1967 and 1971 in Gonzales County, north of Yorktown, at the Dueterstat Site, by, City Service. Other tests were run in Webb County at the Bruni Site, and in Live Oak County at the Burns and Clay-West Sites in the early 1970's. During this period the Texas Water Quality Board maintained a general surveillance of these tests. In mid-1974, Mr. Glen Davis walked into our Austin offices and requested a permit for Atlantic Richfield's first in situ uranium mine. This permit, issued in January, 1975, was for 3 acres of production, and was the first such permit issued in the United States. It formalized the regulation of in-situ uranium mining in Texas. The 4 years since then have been characterized by growth and change. Today there are 20 permits approved for approximately 2,000 production acres. These permits are issued to 8 companies at 13 sites in 6 counties. There are 7 additional permits being processed, or on the verge of being applied for. These will involve possibly another 2,000 production acres, 3 more companies in one more county.

Jan 1, 1979

A study was undertaken to determine the effects of five industrial frothers on the relationship between entrainment recovery and water recovery. The experiments were conducted using a Batequip rectangular 60L steel flotation cell that was run in parallel with the first cell in a copper/silver prefloat rougher circuit. The concentration of the frothers ranged from 2.5 to 8.4 g/t. The experiments were repeated at three different froth depths. A power function was found to fit this relationship with no discontinuity in the relationship caused by the changes in frother type and concentration and froth depth.

Jan 1, 2002

By T. W. Conrad, B. Kerr

During the last decade grassroots minerals education programs have blossomed throughout the United States and in other countries. At the same time an environmental education movement has been gaining momentum. While this offers a unique opportunity to share the mining industry’s story, it also has some potential pitfalls. In this paper the authors will discuss some of the benefits of participating in environmental education and provide some practical tips for success, based on New Mexico experiences. It will conclude with a presentation on a successful environmental education program at Heights Middle School in Farmington New Mexico.

Jan 1, 2001

The American Mining Congress International Coal Show, this year’s largest gathering of coal industry leaders, convened May 5-8 in Chicago. Against a 73 000-m2 backdrop of the coal industry’s most productive equipment,* some 23 000 people heard government and industry executives give guardedly optimistic reports of coal’s near future gains. Although a rocky road lies ahead, operators and suppliers still continue their search to improve efficiency. Among the ideas discussed at the show were better underground communications systems, continuous on-line coal analysis, and recovery of hard-to-float coal.

Jan 7, 1980

By Terrence J. Stobbe

On the job injuries to the musculoskeletal system are probably the oldest of the industrial safety problems. Long before we had pinchpoints to guard, chemical vapors to ventilate, and noise to enclose, people were getting strains, sprains, and sore backs from their work activities. In spite of the age of the problem, it remains a long way from being solved. The past ten years have seen a significant commitment by the sci¬entific community to understanding the problem. Engineers, scientists, doctors, and epidemi¬ologists have been involved, and as a result, today we have a much better understanding of the problem. The first step in understanding a problem such as this is to explore its history and epidemiology. The research done by Chaffin (1977), Snook (1970), Ayoub (1978), the ILO (1962), and others, led NIOSH to publish its Work Practices Guide for Manual Lifting in 1981. The guide was based on research carried out in general industry, but subsequent research by Stobbe (1983) and Peters (1983) has suggested that the nature of the problems producing injuries in underground mining is the same as in general industry. The problems are more intense in the mining environment.

Jan 1, 1984

By David L. Rife

Introduction Our society is currently experiencing a change in civil philosophy toward US industrialization. We have become increasingly bent on the pursuit of a nirvanic state of zero risk. The money supply has become inversely proportional to its sources. And most mining companies, traditionally conservative, have become increasingly risk conscious. Rising taxes, high inflation, and decades of a steadily decreasing gross national product (GNP) - coincident with moral decay and disarmament - have eroded America's economic health. Psychology of US metal markets has shifted across the economic spectrum to disillusionment and discouragement. The sagging national economy, expanding governmental debt, and a backward mineral policy in concert with worldwide unrest and turmoil have caused great volatility in the metal markets. Congressional inaccessibility of US resources has contributed to its loss in strategic leadership and dependency on foreign suppliers and the common market. Large scale mining activities are now on the decline. And there is an overall slump in mineral exploration in this country. America now faces the sobering reality of almost total importation of 13 key mineral commodities and total dependence on foreign sources for five of them. There is a growing dependency on 21 of the 34 minerals vital to the US economy. And virtually everything needed can be imported directly from third world countries. Almost 85% of the free world's supply or production of vanadium, chromium, platinoids, manganese, and titanium - an essential to the aerospace industry - comes from South Africa. That country now plays a forefront position in supplying the West with minerals. The Soviets have become increasingly aware of this situation. They have made key moves in procuring for their own purposes major raw materials markets, particularly in South Africa. This is obviously threatening to the US' direction and brings about vulnerability to shortages and cutoffs. In spite of these developments and the overall change in the mining industry, there is good opportunity for growth ahead. The way has been paved for the smaller mining companies, particularly the more bullish of these. Smaller mining organizations possess a tight management and strong sense of direction. They can easily adapt to and cope with change. "Windows" that exist in the industry directly depend on a number of factors. These include the busi¬ness climate, market research and planning, management and human resources, applied appropriate technology, favorable hunting ground, and entrepreneurship. Mining as business Mining (and exploration) as a business is by its very nature highly speculative. It involves greater risk for a longer period of time than most other businesses. The entire mineral estate in the US continues to shrink. This is primarily because of various legislated wilderness measures. Consequently, the probability of finding an economic ore deposit in the US has decayed to less than 1%. Although the risk is high, the stakes far outweigh the gamble and are larger than most other businesses can offer. Mining properties, as investments or business opportunities, can provide effective hedges against long-term inflation because the real price for selected commodities, such as gold, may sometimes rise faster than inflation. Recessionary periods seem to provide the best climate for entering the mineral business or for a particular mining organization to expand its activities. Looking ahead and seizing opportunities during a depressed market will pay off. Property payments and royalties are likely to be lower. And the potential for an upward shift in prices for a given commodity is very positive. The decision to invest in a prom-

Jan 9, 1985

By Larry Murphy, Mohammad R. Jafari, David M. Giel, Sharat K. Kalluri

"Built in 1940’s to provide a key roadway arterial between New York and Boston, the Heroes Tunnel is the only highway rock tunnel in the state of Connecticut and is part of the Wilbur Cross Parkway. This 365.0 m long tunnel consists of two barrels, each with two lanes of traffic, and carries over 71,000 vehicles per day. For nearly 70 years, the tunnel has seen millions of vehicles pass through but time has taken its toll and now the tunnel lining, ventilation system and radial section joints are significantly deteriorated and in need of rehabilitation. Owned and maintained by the Connecticut Department of Transportation (CTDOT), CTDOT initiated a unique managed approach to mitigate the risk, social impacts and financial implications associated with rehabilitation of this tunnel. This new approach consists of performing field inspection and conducting a comprehensive study to explore six rehabilitation options, including construction of new tunnels and enlarging the existing tunnels. The main criteria for this study are: Impact on traffic and the resulting delay cost; Construction cost; Construction duration; and Construction complexity. This paper will present the results of the alternative study. PROJECT BACKGROUND Location and Importance Heroes Tunnel is located in the State of Connecticut within the Town of Woodbridge and the City of New Haven near the Town of Hamden border. Heroes Tunnel is the only true highway tunnel in the State of Connecticut. The tunnel is part of the Wilbur Cross Parkway (Route 15), a scenic connection between Hartford and New York. Originally constructed and opened to traffic in 1949, the tunneled portion of the parkway passes through the West Rock Ridge. The tunnel was originally named West Rock Tunnel, but was re-designated as Heroes Tunnel in 2003. Route 15 is a vital roadway within the State transportation infrastructure. In the vicinity of Heroes Tunnel, Route 15 carries approximately 71,000 vehicles daily. Locally, Route 15 provides access to residences, shopping centers, and points of interest, as well as other state roadways. Regionally, Route 15 connects New York to the Hartford area and serves as an alternate expressway route to I-95 and I-91. The tunnel is approximately 365.0 m long and passes through the West Rock Ridge. West Rock Ridge is an 11.3 km long rock ridge located on the west side of New Haven. A network of suburban streets abuts the mountain on all sides and a seasonal paved park road climbs to the crest of the ridge. Figure 1 depicts the tunnel topography and location."

Jan 1, 2016