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By P. D. Rao

Chemical and physical properties of typical low-rank coal (LRC) ash are significantly different than bituminous coal ash. With the exception of extraneous ash, which is incorporated during mining or is due to ash partings within or between coal seams, LRC ash consists primarily of inherent ash that is bonded into the coal's organic matrix or finely disseminated mineral matter. This paper reviews the nature of LRC ash, both inherent and extraneous, and how this impacts the prospects of washing and utilizing LRCs. A literature review, as well as washability data, proximate and ultimate analyses and ash analysis of 25 Alaskan LRC seams are used as a basis for this discussion. The authors' recent research into the nature and distribution of phosphorous in an Alaskan LRC is also discussed

Jan 1, 1997

By Eugene M. Trisko

Presentation Overview State-Of-The-Art Scrub/Switch Analyses > Allegheny Power System > PSI Energy UMWA Phase I Coal Interests > 16 Phase I Scrub Plant Coal Profiles > Coal Price/Emission Allowance Interaction Southern Company Case Study > 2+ Million Ton Phase II Allowance Purchases > 10+ Million Ton Phase I Coal Switch > Georgia PSC Proposed Fuel Price Cap > Shift/Avoid Georgia Scub Costs Through System Allowance Purchases

Jan 1, 1993

By Jerry C. Tien

The rare earth elements (REEs) are a group of 17 chemical (metallic) elements which appear in the periodic table. The group consists of 15 lanthanide elements along with yttrium and scandium (Table 1). They share many similar properties, which is why they occur together in geological deposits. Although commonly referred to as rare, they are really quite common; the reason they are perceived as rare is because it is not common to find them in commercially viable concentrations. These metals are critical to advanced technology, ranging from smart phones to global positions system (GPS) receivers, medical devices and jet engines. They are critical in green, high-tech and defense industries (Fig.1 and 2). Although there have been increasing efforts to find alternative supplies, these efforts have been complicated by the pollution that rare earth mining and processing creates. To extract rare earths minerals from mined ore is a complicated and costly process. The ore is first mined through normal mining process, the bastnaesite, which generally contains a number of minerals of little value, is first removed through a floatation process. The bastnaesite containing the REEs is further separated into their respective pure forms in a separation plant using acid and various solvent extraction separation steps. Each element has its own unique extraction steps and chemical processes. At times, these elements, in the form of oxides, will require reprocessing to achieve ideal purity. The last steps would be to further process into metals first, then alloys for various applications. The entire process takes approximately 10 days. The mining and processing of REEs, if not carefully controlled, can create environmental hazards. This is one of the reasons the Mountain Pass Mine in California was closed down in the 1980s.

Dec 1, 2013

By David J. Boron

The United States has the largest total (364 billion metric tons) and recoverable (182 billion metric tons) coal reserves in the world.1 However, progressive coal utilization in this country has been hampered by environmental constraints, such as restrictions on sulfur dioxide, nitrogen oxides, and particulate emissions. New technologies are being pursued both to appease these environmental concerns and improve economic performance and process efficiency. These technologies, however, have not reached the level of effectiveness required for optimum operation. If more stringent emission standards are imposed, it is likely that the coal industry, and the industrial and utility sectors will look increasingly toward the successful development of new and advanced coal cleaning technologies in order to continue and promote the use of coal in this country. The EPA New Source Performance Standards In 1979, the Environmental Protection Agency in response to the amendments to the Clean Air Act of 1977 issued new source performance standards (NSPS) for utility and industrial boilers. The NSPS set emission standards for sulfur dioxide, nitrogen oxides, and particulates affecting boilers of 250 MM Btu per hour heat input or 'greater that started construction after September 1978. Plants starting construction or in operation before September 1978 remained subject to the provisions of the regulations promulgated in 1971, i.e., SO2 emissions of 1.2 15/MM Btu. The NSPS for SO2 emissions provides a sliding scale for SO2 reduction depending on the sulfur content of the run-of-mine coal, with an upper limit of 1.2 lb of SO2 per million Btu and a minimum emission level based on 70% SO2 removal. Table 1 summarizes the EPA NSPS for SO2 emission standards.

Jan 1, 1983

By D. G. Krige

I read the paper “The jackknife approach” with interest. There appears to be a widespread misunderstanding of the kriging variance as a measure of the error variance of the kriged grade estimate of an ore block. Virtually all mineral deposits display skew frequency distributions and are subject to the well-known proportional effect. Thus, it is usual to find in an ore body, when subdivided a really into subpopulations, that the variances of the grades (or the total sills of the variograms) for the subpopulations will be correlated with the corresponding mean grades (usually linearly with the squares of the mean grades). Thus, the variogram will be stationary.

Jan 1, 1996

By Miguel Angel Ibarra

This paper describes the results of a digital computer simulation study in which the impact of the proposed truck dispatching on the overall mine productivity was investigated for an operating open pit mine. In the study, the existing operation was first simulated for a one-month period, using both the actual time study data and the computed cycle times. By adjusting certain input parameters to the simulation program, the actual one month production was first duplicated through simulation. Afterwards, the operation was again simulated in a dispatch mode. Comparison of simulation results under the dispatch mode, with the initial base case simulation results, showed a definite improvement in overall productivity with dispatching; i.e., approximately 10% gain for the operation. As expected, the results also showed that the extent of possible improvement did vary with the particular pit configuration being investigated.

Jan 1, 1980

By J. García, B. Arango, F. Calderón, O. J. Restrepo-Baena, A. Carreno, L. Rojas-Mendoza, J. Pérez, E. Bedoya

"Tungsten extraction is a subject of global interest due to is properties. These properties, such as its high melting point, have contributed to the development of metallurgical extraction processes that can be adapted to the particular chemical composition and mineralogy of the ore. In Colombia there is a research deficit in tungsten related areas, and especially with regard to its extractive metallurgy. In this study the physical, chemical and mineralogical characterization of a sample were performed. Subsequently, crushing and grinding were employed to reduce the material to a more convenient size, making it suitable for further concentration and metallurgical processes. Through physical concentration techniques it was obtained a concentrated ranging between 60 -70 % of WO3 content.INTRODUCTION Tungsten is a metal of great economic importance due to its excellent properties such as high density and extraordinary melting point 3422°C), which is indeed the highest of all the elements. Tungsten is primarily used in metal alloys, manufacture of special steels, coatings and catalysts; products of interest to both international and national industry. However; given that the use and economic value is determined by the percentage of tungsten in the mineral, particle size and chemical associations, it becomes essential to properly characterize the mineral to further define possible metallurgical extraction routes. The metallurgical processes for minerals enriched in tungsten may vary depending on location and the genesis of the ore body, which means that for each ore a particular set of operating conditions must be determined. This is important since process standardization can lead to misuse of the mineral resource. However, in Colombia there is a research deficit as it relates to minerals enriched in tungsten and to its extractive metallurgy. Then, there is a need to conduct studies that can lead to a better understanding of the ore, and to develop extraction processes for the metal of interest. EXPERIMENTAL A state of the art review was made in order to gain insights of the tungsten metallurgical process. Comminution was necessary with the aim to reduce the sample size; therefore the sample was taken into crushing and grinding stages. Concentration techniques such as magnetic separation, gravity and / or electrostatic were also applied. Physical, chemical and mineralogical characterization were performed by using polished sections, grain size determination, X-Ray Fluorescence (XRF) and X-ray diffraction (XRD) techniques."

Jan 1, 2015

By Eric Lundgren

The mining paradigm is changing on the continent of Africa. Jessica Kogel?s closing statement from her September 2013 President?s Page (ME, September 2013, pp. 6) has never been more appropriate, ?Africa is shaping up to be the next mining powerhouse, and there is huge opportunity for local communities, national governments and private industry to work together to create a win-win situation for all.? Supporting this notion, attendance at numerous industry conferences around the world demonstrates the shift toward a more sustainable, more environmentally conscious extractive model. But questions remain: How effectively is the industry making this transition, and how willing are companies to learn from the experiences of others? The international development community, as we like to call ourselves, is going through a parallel shift. We are experiencing our own funding crisis; governments are not as flush with resources as they were pre-economic meltdown. But more importantly, after a half century of implementing development programs, we must admit that while some of our programs have been fantastically successful, too many still fail to achieve the goal of poverty alleviation for the world?s poorest. Moving forward, we are forced to recognize that achieving success in scale and sustainability is not always accomplished from our work alone. As the director of international programs for Africare, a nonprofit with more than 40 years of experience implementing community-based development programs in Africa, I can report that our organization is changing the way we think about successful development partnerships. Africare recognizes that for too long the mining sector and nonprofits have been at odds, choosing noncommunication as a ?solution? to the problem. Both sides now recognize that this standoff is outdated, and Africare, specifically, is ready to cross the proverbial line. We see the potential benefits of mining for local communities and, when done responsibly, the opportunity to properly manage Africa?s resource boom as a benefit to all. There are challenges in this conversation. Many mining professionals view nonprofits as whistle-blowers, ready in a pinch to speak to news sources and complain about poor operational standards. Those are advocacy organizations, and while their role is important, they are not the only nonprofits interested in mining operations in developing countries. Organizations like Africare, with decades of experience implementing poverty reduction programs, approach this differently. We know we can work with mining companies to promote economic opportunity in the communities where mining operations are occurring. We recognize that the conversation is difficult, and we are open to discussions about how we can bring our unique experience to bear on the problems faced by mining companies in carrying out their investment programs.

Jan 1, 2014

By J. -M. Lopez-Cuesta, C. Petter, B. Otazaghine, M. Batistella, R. Sonnier

"Kaolinite is a dioctahedral aluminosilicate widely used as paper filler and coating pigment. At the best of our knowledge, kaolinite is not widely used in polymer industry. Therefore, in this study, the flame retardant effect of kaolinite in ethylene vinyl acetate copolymer (EVA) and polypropylene (PP) were studied and compared with an alumina trihydrate (ATH) and Talc. Cone calorimeter results shows that the weight percentage of ATH in EVA/ATH composites must be at least 50 wt. % in order to reach an improvement in fire retardancy in terms of pHRR. In the case of EVA/kaolinite, even with 35 wt. % the pHRR is largely reduced. Comparing PP/Talc and PP/kaolinite composites at 30 wt. %, both fillers leads to same reduction in pHRR with a slightly better performance for PP/kaolinite composites. In both cases an intumescent behavior of kaolinite composites was observed that could slow the rate of the rising degradation products, allowing radical recombination reactions. Also, it was observed that kaolinite forms a protective layer on the surface of the samples, which could insulate the material. These behaviors (intumescence and formation of a protective barrier) could reduce the transfer of the degradation products to the flame and explain the better performance of kaolinite composites. INTRODUCTION The use of mineral fillers as fire retardants in polymer matrix are well known and widely studied [1]–[10]. Aluminum and magnesium hydroxides (respectively ATH and MDH) are the most widely used inorganic fire retardants. To achieve fire retardancy with these mineral fillers, about 50-60% loading is required which decrease the physical properties of the composites. The fire behavior of composite EVA has been the subject of many studies [4], [7], [9]–[15]. EVA copolymers are commonly used in the cable industry, due to their high ductility, even at high loading rates. In such applications, the flame retardant systems should be introduced into the polymer to improve the fire reaction. Many flame retardant systems have been tested but the most used industrially relates to formulations based on hydrated mineral fillers (aluminum hydroxide and magnesium hydroxide). Their low cost and reduced fumes generation explains their success. However, to obtain good performance with this type of flame retardants, it is necessary to incorporate high levels (up to 65 wt %), which severely impact other properties such as processability and mechanical behavior. The main modes of action of these flame retardants are the dilution of the gas phase, the endothermic decomposition and a barrier effect created by the inorganic oxide residue which may be improved by the incorporation of other components such as montmorillonites, silicas or talcs."

Jan 1, 2015

By Siddhartha Roy, Hemant Agrawal, Ram Madhab Bhattacharjee, Devi Prasad Mishra

The paper addresses heat stress in underground coal mines, which poses significant threats to miners’ health, safety, and productivity. It involves a comprehensive ventilation survey in three deep and mechanized underground coal mines in India. Using VentSim software, 3D simulation models were developed to predict heat stress conditions and explore the application of auxiliary ventilation and spot coolers to reduce heat stress.

Oct 1, 2023

By James M. Barker

The occurrence of borates and zeolites at Mesa del Alamo is well documented by McAnulty and Hoffer (1) and Lefond and Barker (2). Further investigation indicates the presence of priceite and meyerhofferite in addition to the howlite (1) and colemanite (2). Analcime occurs in addition to the clinoptilolite and phillipsite (2). The Mesa del Alamo area is about 200 !a south of Tucson, Arizona, and 13 km southeast of Magdalena, Sonora, Mexico, just south of the unpaved road to Cucurpe (Figure 1). The geology and mineralogy of northcentral Sonora is known only on a regional basis except for small areas mapped in detail during copper exploration. The study area is within the Basin and Range province of North America from which borates and zeolites are now produced in California. The borates and zeolites at Mesa del Alamo occur in geological environments similar to those of the Mojave and Death Valley regions of California (3, 4). Thus, a detailed exploration pro- gram in the Magdalena area could result in the discovery of economic borate and/or zeolite deposits.

Jan 1, 1979

By VÍCTOR VÁZQUEZ-VÁZQUEZ, GUILLERMO TIBURCIO-MUNIVE, María M. Salazar-Campoy, JESÚS L. VALENZUELA-GARCÍA, OFELIA HERNÁNDEZ-NEGRETE

This study examines a process for the recovery of precious metals from difficult minerals that exhibit refractory characteristics to cyanidation: low extraction of metals and high consumption of leaching reagent. A mineral sample from Monte del Favor Mine, located in Hostotipaquillo, Jalisco, Mexico, was physically and chemically characterized by X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), fire assay and atomic absorption spectroscopy (AAS). Two stages of leaching were carried out, first to eliminate manganese from the sample using sodium sulfite (Na2SO3) as a reductive reagent along with sulfuric acid (H2SO4), and second to dissolve gold and silver with hydrochloric acid (HCl) and sodium hypochlorite (NaClO). The results show extractions of around 96 percent for manganese (Mn), 98.73 percent for silver (Ag) and 83 percent for gold (Au). The usefulness of high acidity and Na2SO3 to obtain better results in Mn and Ag leaching are discussed along with the roles that HCl and NaClO play in Ag and Au dissolution values.

By L. Zhou, L. Yuan, R. A. Thomas, D. Bahrami

The abstract emphasizes the importance of a calibrated ventilation network model for mine ventilation planning, optimization, and fire simulation. It highlights the impact of continuous airflow monitoring on improving model calibration. The paper discusses an experimental study at the Safety Research Coal Mine (SRCM) to understand the use of continuous airflow data for model improvement. It also addresses practical problems in calibration and tuning using this data, including analysis of air velocity sensor fluctuations and application of sensor location correction factors for accurate average air velocity.

Mar 7, 2022

By J. C. Johnson

The problem of estimating pillar capacity in coal mines has motivated development of a variety of empirical equations. Most of these equations have arisen from experience and a very limited set of measurements that have, necessarily, been focused on particular regions or coal fields. Their applicability is often limited to a specific range of pillar sizes. This is of particular concern in the design of large gateroad pillars and small barrier pillars between panels. The result has been a variety of equations and equation coefficients that can calculate load estimates to size pillars. Inclusion of these equations in more sophisticated loading models, such as boundary element methods (e.g. LaModel and MULSIM) has been hampered by absence of a function that describes specific variation of coal strength within the pillar. A singular exception, to our knowledge, is a function corresponding to the Bieniawski pillar strength equation. Because of this, it is the only coal strength criteria inherently available in most boundary element models. This paper presents a general method for deriving local coal strength, as a function of distance from the pillar rib, for an arbitrary pillar strength equation. Integration of this function provides the strength of pillar regions, or cells, needed for boundary element models. The method is demonstrated for the Bieniawski, Maleki and Holland-Gaddy equations. The Maleki and Holland-Gaddy equations contrast strongly with Bieniawski as strengths are extrapolated to large pillars and barriers. This development provides a tool for incorporating any of the proposed empirical equations into a boundary element model, thereby allowing the analyst to choose the most appropriate equation for a particular region, coal seam and/or pillar size.

Feb 23, 2014

By K. M. Belingheri, M. E. Smith

Pinson Mining Co. operates a conventional mill and two heap leach operations in north-central Nevada. The latest of these heap leach operations, the Preble project, is a low-grade, low-tonnage property made profitable through several innovative capital reduction techniques. Rapid return on investment was a prime factor in design. To facilitate this, fast-track design and construction techniques were employed. The project is a seasonal 1.5 kt/d (1 700 stpd) crush/agglomerate heap leach plant using both clay and plastic leach pads. Construction and startup were achieved through cooperative arrangements between local contractors and in-house construction personnel, with few items put out to bid. An interactive approach to design minimized lost time and construction costs.

Jan 1, 1987

By Henry N. McCarl

From the earliest use of crushed and broken stone as landfill for eroded gullies in trails and roads, to the mixing of sand and gravel with cement to make concrete, men and women have found mineral aggregates to be useful materials in satisfying human wants. Crushed stone, sand and gravel, volcanic cinders, pumice, manufactured lightweight aggregates, slag, cinders, expanded perlite and vermiculite, and a great array of recycled materials such as grog (broken or crushed brick) and fly ash have served as mineral aggregates. These materials have provided bulk and strength in portland cement concrete, bituminous concrete, road base, fill, concrete block, and plaster and stucco finishes. Mineral aggregates provide many special characteristics such as compressive and tensile strength, surface textures, weight and density, thermal and acoustical insulation, abrasion resistance, and impermeability to various concrete products and mixes. While most materials used as mineral aggregates are consumed on the basis of their low unit values, the large volumes extracted in the United States each year make them one of the most valuable mineral resources in current production. In 1960, US production of construction aggregate was just over a billion tons per year (Meyer and Zelnick, 1991). Two decades of accelerated interstate highway, residential, and commercial construction brought the total annual production of mineral aggregates to roughly 1.4 Gtpy by 1970 and just over 1.6 Gtpy by the late 1970s. General economic and related construction slowdowns in the early 1980s saw annual US production of aggregates fall to below 1.1 Gt in 1982, and then rise to just over 1.7 Gtpy in 1990, a new peak in mineral aggregate production and use. Per capita annual consumption of mineral aggregates was approximately 5.68 t/capita in 1960, 6.89 t/capita in 1970, rose to a high of 7.25 t/capita in 1979, and has since settled to just under 7 tpy for every man, woman, and child counted in the United States Census of 1990. The value of these materials came to approximately $9 billion in 1990. During the period 1960-1990, roughly half of all mineral aggregates were used in the construction of residential, commercial, and industrial structures, and the remainder was consumed in highways, bridges, and other transportation facilities such as railway roadbeds, airports, and water-related projects (Meyer and Zelnick, 1991). During the period 1988-1992, public works (highways, waterway projects, road maintenance, etc.) represented closer to 60% of annual mineral aggregate demand with residential and non-residential construction approximately 40%. The growing market share of public works projects has been mostly due to the dramatic slowdown in residential, commercial, and industrial construction during the 1988-1992 period.

Jan 1, 1994

By Thomas Pea, Heiner Kontrus, Jérôme Steinkühler

In tunnel condition assessment, the trend is towards comprehensive 3D measurement combined with high quality image texture to document and quantify damages to the tunnel surface and to create a cohesive data base of the structural conditions throughout its lifespan. The faster such measurements can be made on site, the less it impacts traffic conditions of the highly sophisticated subway systems. The Dibit high-speed 3D scanning system which is based on Photogrammetry and LiDAR technology enables data acquisition in tunnels at a speed of up to 60 mph. Given the high rate of speed the system can operate, tunnel shutdowns can be drastically reduced, and tunnel safety increased. The photorealistic texturing of the 3D-model allows the identification and analysis of smallest material damage (e.g., cracks ≥0.3 mm wide). The publication illustrates technical details and 3D results of the innovative system from measurements that were performed in the subway tunnels of the Bay Area Rapid Transit System in San Francisco, CA (total length 66.23 km).

Jun 13, 2021

By Sean Hunter

Artificial Intelligence has a long history but is currently coming strongly into focus with new advancements. This leads to questions many people are asking: what exactly is AI, how can it be used effectively in mining operations, and what foundation is required to make AI implementations successful? In mining, many AI applications exist, from drill pattern optimization to predictive maintenance. However, many implementations struggle due to data integration challenges. Mining operations generate large amounts of data from many sources, such as fleet management systems, drill sensors, process control systems, and laboratory results. Unfortunately, this data often exists in silos where it’s difficult to get it out, making AI applications unable to leverage it. Worse still, tools that use AI don’t always provide their data back to the system, creating even further data silos. All these problems make it hard to take advantage of the data at the mine, slowing down and reducing the effectiveness of AI. This paper presents a comprehensive approach to organizing mining data using an AI-ready knowledge graph system. We will first explore the evolution of AI in mining, from early expert systems to modern machine learning applications. Then, we will detail how a knowledge graph can integrate business context, operational data, and AI models into a cohesive system that enables more effective AI implementations across mining operations. The proposed method has been developed considering both the unique data challenges faced by the mining industry, while also considering best practices learned from the AI field at large. By following this approach, it’s possible to better utilize existing data, getting higher quality and more complete results faster, and in a way that’s reusable and composable.

Feb 1, 2025

By Sandro Moro, Giuseppe Tiberti, Giovanni Plizzari, Antonio Conforti

"During TBM operations, thrust jacks apply high-concentrated forces to the last installed precast segment. These loads generate a disturbed region in the precast segment under the thrust jacks, in which significant tensile stresses (defined as splitting or bursting stresses) occur perpendicular to the load direction. In addition, due to the demand of compatibility, the combined effect of TBM high-concentrated loads determines tensile spalling stresses in the area far from the loads. Therefore, local rebars or fiber reinforcement are required in these areas. This paper focuses on the study of the effects generated by high-concentrated loads exerted by TBM hydraulic jacks, mainly in terms of both spalling and splitting phenomena. Experimental tests on small-scale specimens showed that polypropylene fiber reinforcement significantly enhances both the bearing capacity and the ductility. Moreover, polypropylene fibers resulted in very effective control of compatibility cracks.INTRODUCTIONTunnel segments are generally reinforced by conventional rebars (RC segments) in order to resist the tensile stresses both at Serviceability (SLS) and Ultimate Limit States (ULS).In the two last decades, Fiber Reinforced Concrete (FRC) has been used in many precast tunnel segments (sometimes also in combination with conventional rebars). Steel Fiber Reinforced Concrete (SFRC) is generally used for these applications even though there is a growing industry interest on macro-synthetic fibers for structural applications. Conforti et al. (2015) showed that polypropylene (PP) macro fibers can be used as shear reinforcement in both wide shallow and deep beams. Referring to precast tunnel linings, very few early experiences are reported in literature. Bonalumi et al. (2015) developed full-scale tests on tunnel elements reinforced by PP fiber reinforcement and conventional rebars (hybrid solution). The design process of segmental concrete tunnel linings generally models the standard load cases of demolding, storage, transportation, positioning and embedded ground condition. In all these stages the ring can be modelled as simple curved beam elements (having a height equal to the lining thickness and a width equal to the segment length). During these loading conditions, flexural demand is generally limited; thus, in case of conventional RC elements, a rather low ratio of longitudinal curved rebars is usually adopted (?s of about 0.2-0.3%)."

Jan 1, 2016

By Rakesh Sehgal, Pushkar Verma, Mohit Sharma

"SJVN Limited successfully commissioned its Rampur HEP (412 MW) in 2014. The project has been planned to operate in tandem by directly utilizing the Tail Water of SJVN’s prestigious Nathpa Jhakri Hydro Power Station 1500 MW located upstream. The initial filling of voluminous water conductor system of RHEP with 10.50 m diameter, 15 Kilometer long Head Race Tunnel, involved more than 1.5 million m3 of water. The filling operation of such a large diameter tunnel constructed in young folded Himalayas which always offer less ideal sites for tunnelling and their subsequent operations under pressurized conditions is worth sharing with tunnelling fraternity. The paper covers meticulous planning, execution, precautions taken, and performance monitoring during filling process keeping in view the fragile geology, low rock cover zones, shear zones in close vicinity of thickly inhabited areas, squeezing zones, hot water zones encountered during excavation.1.0 RAMPUR HYDRO POWER STATION IN BRIEFRampur Hydroelectric Project (412 MW), is located in Himachal Pradesh (India). This project is a downstream development of Nathpa Jhakri Hydro Power Station (1500 MW) constructed on river Satluj and commissioned during 2003. Both the projects today are now successfully working in tandem. The upstream NJHPS has been constructed on the left bank of the river while the downstream Rampur HPS is located on right bank of the river (Figure-1).The major length of HRT of Rampur project lies on right bank of river before it crosses under the river in its initial reach (Figure-2). The main features of the project are as below:• 10.50 m diameter 15 km long HRT ending in a 155.75 m deep, 38.00 m diameter surge shaft.• 3 steel lined pressure shafts, 5.4 m dia, 211-220m long.• Surface valve house 69 m long x 10.50 m wide x 23 m high housing 3 No. butterfly valves• 3 No. surface penstocks 5.4m dia 368-382m long, bifurcating into six penstocks, each of 3.80 mdia. to feed six generating units of surface power house 158 m long x 24.50 m wide x 48 m high, with Francis turbines each of 68.67 MW capacity."

Jan 1, 2016