This paper was presented at the Seminar on "National Brain storming session on Mechanization of underground coal mines"- organized by SECL (Coal India) at Bilaspur.
This document describes how a mining company in India used an innovative monorail transport system to replace the Armoured Face Conveyor (AFC) pans in a working longwall panel. The conventional method of replacing AFC pans takes 15-20 days but the monorail system allowed the company to complete the replacement in just 8 days, saving time, production losses, and costs. The monorail system involved installing rails along the face and using a bogie with lifting capabilities to remove the old pans and transport new pans into place more quickly and safely than conventional methods.
1. The document describes the dragline planning process which involves reviewing previous strip performance, geology, structures, access, and interactions to generate a dragline design.
2. Key steps include projecting coal edges and toe lines, offsetting lines, and using triangles between lines and profiles to create the highwall, lowwall, and spoil surfaces.
3. The design is then used to create a spoil balance, range diagrams, 3D dig model, and micro schedule for dragline digging.
This document summarizes a case study on the effect of underlying goaves on subsidence for a longwall mining panel at shallow depth. Empirical equations were developed based on subsidence profiles from previous panels to predict subsidence. The equations account for panel width, depth, and percentage of underlying goaf area. For panel 1A, the predicted profile using these equations matched well with the actual profile, demonstrating the equations can accurately estimate subsidence when accounting for underlying goaves. The maximum observed subsidence of 1.46m for panel 1A was less than the estimated 2.2m, likely due to the panel being split into two smaller sections.
Lecture 6 s.s.iii Design of Steel Structures - Faculty of Civil Engineering IaşiUrsachi Răzvan
The document discusses the design of runway girders that support overhead cranes. It describes various types of runway girder configurations including single plate girders, built-up box sections, and lattice girders. It also outlines the loads that act on these girders including the self-weight of the girder and rails, as well as vertical and horizontal forces from the moving crane. Design is checked against limit states including bending capacity, buckling, fatigue limits, and serviceability deflections. Equations are provided to calculate stresses in different parts of the girder from these loads.
Massarsch uevos desarrollos en pilotes de fundacióncfpbolivia
This document discusses new developments in pile foundations, including:
- Auger cast piles which can risk soil decompression during installation if penetration and extraction speeds are too high or low, and which benefit from installation monitoring and reinforcement placement;
- Piles with expander bodies which allow pile length and shaft diameter reduction, known base shape, soil recompression, and installation quality control;
- Vibrated steel piles with expander bodies which provide quick installation and avoid soil decompression;
- Vibrated conical concrete nails which provide an alternative to stone columns or piles for settlement reduction through vibratory compaction during installation.
The document discusses literature related to longwall mining geo-technical studies conducted at Ramagundam region in SCCL, India. It summarizes the key findings from 9 completed longwall panels at GDK.10A incline mine including production trends, geological conditions, equipment specifications, and analyses of caving behavior and periodic weighting distances for different panel lengths. Face length was found to influence main and periodic fall spans, with main fall varying between 63-78m for face lengths from 90-170m.
Piling work method statement cm- ms- bw - 002Minh Bui Si
This document provides a method statement for pile driving works for buildings at the Cai Mep International Container Terminal project in Vietnam. It outlines the scope of work, which includes supplying and driving precast concrete piles (PHC piles) and solid concrete piles. The document describes the equipment and labor to be used, including pile hammers, cranes, and a workforce of 33 people. It also provides details on pile fabrication, transportation, storage, driving procedures, quality control checks, safety measures, and appendices with supporting documents.
This document provides information about launching girders for bridge construction. It discusses the necessary preparations before launching including completing abutments and piers. It describes the launching equipment used such as the steel launching girder, winches, and trolleys. The document outlines the process for shifting the launching girder and launching precast concrete girders segment by segment onto the bridge. It compares different launching techniques and discusses advantages such as allowing construction at any height and simultaneous work on substructure and superstructure.
This document describes how a mining company in India used an innovative monorail transport system to replace the Armoured Face Conveyor (AFC) pans in a working longwall panel. The conventional method of replacing AFC pans takes 15-20 days but the monorail system allowed the company to complete the replacement in just 8 days, saving time, production losses, and costs. The monorail system involved installing rails along the face and using a bogie with lifting capabilities to remove the old pans and transport new pans into place more quickly and safely than conventional methods.
1. The document describes the dragline planning process which involves reviewing previous strip performance, geology, structures, access, and interactions to generate a dragline design.
2. Key steps include projecting coal edges and toe lines, offsetting lines, and using triangles between lines and profiles to create the highwall, lowwall, and spoil surfaces.
3. The design is then used to create a spoil balance, range diagrams, 3D dig model, and micro schedule for dragline digging.
This document summarizes a case study on the effect of underlying goaves on subsidence for a longwall mining panel at shallow depth. Empirical equations were developed based on subsidence profiles from previous panels to predict subsidence. The equations account for panel width, depth, and percentage of underlying goaf area. For panel 1A, the predicted profile using these equations matched well with the actual profile, demonstrating the equations can accurately estimate subsidence when accounting for underlying goaves. The maximum observed subsidence of 1.46m for panel 1A was less than the estimated 2.2m, likely due to the panel being split into two smaller sections.
Lecture 6 s.s.iii Design of Steel Structures - Faculty of Civil Engineering IaşiUrsachi Răzvan
The document discusses the design of runway girders that support overhead cranes. It describes various types of runway girder configurations including single plate girders, built-up box sections, and lattice girders. It also outlines the loads that act on these girders including the self-weight of the girder and rails, as well as vertical and horizontal forces from the moving crane. Design is checked against limit states including bending capacity, buckling, fatigue limits, and serviceability deflections. Equations are provided to calculate stresses in different parts of the girder from these loads.
Massarsch uevos desarrollos en pilotes de fundacióncfpbolivia
This document discusses new developments in pile foundations, including:
- Auger cast piles which can risk soil decompression during installation if penetration and extraction speeds are too high or low, and which benefit from installation monitoring and reinforcement placement;
- Piles with expander bodies which allow pile length and shaft diameter reduction, known base shape, soil recompression, and installation quality control;
- Vibrated steel piles with expander bodies which provide quick installation and avoid soil decompression;
- Vibrated conical concrete nails which provide an alternative to stone columns or piles for settlement reduction through vibratory compaction during installation.
The document discusses literature related to longwall mining geo-technical studies conducted at Ramagundam region in SCCL, India. It summarizes the key findings from 9 completed longwall panels at GDK.10A incline mine including production trends, geological conditions, equipment specifications, and analyses of caving behavior and periodic weighting distances for different panel lengths. Face length was found to influence main and periodic fall spans, with main fall varying between 63-78m for face lengths from 90-170m.
Piling work method statement cm- ms- bw - 002Minh Bui Si
This document provides a method statement for pile driving works for buildings at the Cai Mep International Container Terminal project in Vietnam. It outlines the scope of work, which includes supplying and driving precast concrete piles (PHC piles) and solid concrete piles. The document describes the equipment and labor to be used, including pile hammers, cranes, and a workforce of 33 people. It also provides details on pile fabrication, transportation, storage, driving procedures, quality control checks, safety measures, and appendices with supporting documents.
This document provides information about launching girders for bridge construction. It discusses the necessary preparations before launching including completing abutments and piers. It describes the launching equipment used such as the steel launching girder, winches, and trolleys. The document outlines the process for shifting the launching girder and launching precast concrete girders segment by segment onto the bridge. It compares different launching techniques and discusses advantages such as allowing construction at any height and simultaneous work on substructure and superstructure.
This document discusses Benkelman beam deflection studies, which are used to evaluate the structural capacity of existing pavements and estimate overlay designs for strengthening weak pavements. The Benkelman beam test procedure involves measuring the rebound deflection of a pavement under a standard wheel load. Deflection measurements are taken at intervals along the road using the Benkelman beam and loaded truck. The results are used to calculate the true rebound deflection and characterize pavement strength statistically based on mean, standard deviation, and characteristic deflection values. Overlay design is then determined based on the statistical analysis.
The document discusses methods for stabilizing slopes through terracing or constructing benches. Specifically, it describes:
1) Building benches or flat areas into slopes to break them up into smaller slopes and improve stability. Dimensions of typical benches are mentioned.
2) Modifying the slope geometry, such as through controlled excavation, to redistribute forces and create a more stable configuration.
3) The purpose of benches is to slow water flow, drain water away from slopes, and prevent erosion and scouring that can destabilize slopes. Proper bench design and drainage is important for stability.
This document discusses various methods and standards for measuring pavement surface characteristics like skid resistance and texture. It covers topics like factors that influence skid resistance, methods for measuring micro-texture and macro-texture, standards for measuring polished stone value, and devices for measuring skid resistance at different speeds. The summary provides an overview of the key methods and standards discussed in the document.
This document provides details of Structural Fabrications Ltd, a company that has worked in the water industry for over 15 years. It has worked with several major water companies on various projects. Recently, it was approved by Severn Trent on a 5-year framework for fabrication work. The company serves customers across the UK and provides examples of recent projects it has completed for water treatment plants and pumping stations. These involve installations like lifting gantries, davits, and platforms.
This document discusses tunnel support design in weak rock. It presents concepts for how the rock mass surrounding a tunnel deforms and how support systems act to control deformation. Dimensionless plots show tunnel deformation increases substantially if rock mass strength is less than 20% of the in-situ stress and tunnel closure exceeds 1% of the diameter. A practical example determines support needs for a drainage tunnel based on geotechnical parameters. Steel ribs are selected to generate over 1 MPa of internal support pressure to limit convergence to under 2%.
The document describes the key features of a river diversion arrangement and roller compacted concrete dam for the Jamrani Dam Multipurpose Project. The river diversion includes upstream and downstream cofferdams and a 6.5m diameter tunnel. The 150.6m high RCC dam has a 9km long reservoir and is designed to withstand a probable maximum flood of 8472 cumecs. Stability analyses were conducted considering loads such as earthquake, uplift, and hydrostatic forces, and stresses were found to have adequate factors of safety under all loading conditions.
A casting yard is where concrete structures like segments, parapets, and beams are cast for bridges and viaducts. It must be easily accessible from project sites and have 25-40 acres of land. Concrete elements are cast using long-line or short-line methods, cured, and then transported to worksites. Quality control includes geometry control during casting and testing of concrete slump, setting time, and compressive strength. Precast concrete has higher quality control compared to cast-in-place concrete.
The document discusses the preliminary studies required for the geometric design of roads, including their classification, basic design criteria, engineering considerations, and standards. It covers analyzing demand and terrain, conducting surveys, studying hydrology, geology, environment and safety. The goal is to design roads appropriately based on capacity and standards according to road classification and terrain conditions.
Types of Pavements, Layers present in the pavements, Stresses on the rigid pavements, wheel load, repetitions etc.. and Indian Standard Method of design of Rigid Pavements.
Effect of l b ratio of stone column on bearing capacity and relative settleme...IAEME Publication
This study experimentally analyzed the effect of L/B ratio of stone columns on the bearing capacity and settlement of sandy soil. Model tests were conducted with a square footing and single stone column with L/B ratios of 0.5, 1, 2, 2.5, and 3. The results showed that the minimum relative settlement corresponded to an L/B ratio of 2.5, which also had the highest bearing capacity of 318 kN/m2. Increasing the L/B ratio beyond 2.5 did not significantly improve the bearing capacity. Thus, the optimal L/B ratio for a single stone column was determined to be 2.5 based on minimizing settlement and maximizing capacity.
critical review of extraction of strike longwalls versus dip rise longwall panels in SCCL AP india, operational and planning parametres to be considered for working the same
The document outlines the rules for loads that must be considered in designing and assessing the strength of railway bridges in India. It specifies loads like dead loads, live loads, dynamic effects, wind pressure, seismic forces, temperature effects, and derailment loads. Live loads have increased over time from 18 tonnes per axle in 1903 to 32.5 tonnes per axle currently for the highest class. Dynamic load effects are quantified using a coefficient between 0.15 and 1.0 depending on bridge properties. Seismic forces also depend on the zone the bridge is located in, with zones II-V having increasing seismic specifications.
This document summarizes a student's research poster presentation on redeveloping the shoulder design for an embedded light rail track. The student investigated reasons for deterioration of the concrete shoulders on Dublin's light rail system and proposed alternative solutions. The poster described a case study of a section with deteriorated shoulders. It outlined negatives of the original reinforced concrete slab and concrete shoulder design, and presented a new design replacing the concrete shoulder with asphalt and adding angle brackets to enhance rail stability. Design calculations were provided to show the new design met strength requirements.
The Rion-Antirion Bridge in Greece connects the Peloponnese peninsula to the western mainland via a 2252m long cable-stayed main bridge that spans the Corinth Strait. It was designed to withstand the severe seismic activity and possible fault movements in the area. The main bridge uses four pylons supported by large reinforced soil foundations to distribute seismic forces to the deep weak soil layers. Dynamic analysis showed that during major earthquakes, the reinforced soil and pylon foundations would yield and slide as designed to dissipate energy without compromising the structure. The continuous suspended deck acts as a flexible element that can accommodate displacements without damage. The bridge's innovative design allows all components to work together to resist earthquake forces through
The main outcome of this project is the construction sequence of HMR which primarily starts with excavation, erection of piers, launching girder process and assembling of segments. This project clearly gives a brief knowledge on how the post tensioning and pre stressing works are held at off site and onsite. This project enlightens about the safety requirements and measures taken during the pre-casting works and at on site works.
The document summarizes the design of a 787.8m long flyover with 22 piers and 2 abutments located in Mathura, India. It includes the design of the deck slab, longitudinal and cross girders, piers, and foundations. Pigeaud's and Courbon's methods were used to design the deck slab and girders respectively. Reinforcement details are provided for all elements following Indian design codes. The flyover has a 250mm thick deck slab with 16mm and 12mm bars and 1.575m deep longitudinal girders with 32mm bars. Piers are 2-2.5m in diameter with 28mm or 25mm longitudinal bars. Foundations are 10.
This document summarizes the components, erection procedures, and safety precautions for launching girders used in bridge construction. It describes the main components of launching girders including the main box girder, front support, middle support, and rear support. The erection process is outlined involving assembling the girder, erecting supports, lifting segments, and auto launching. Key safety measures are identified for erection activities and auto launching to control risks like falls, collisions, and structural collapse. A hazard identification and risk assessment is also conducted to rate risks and identify additional safety controls.
The document provides information on various aspects of metro projects, including common terminology used, the different types of metro systems (elevated, underground, on grade), and construction methods. It discusses features of elevated and underground metros such as viaducts, stations, tunnels, and cut-and-cover construction. Diagrams and photos show the construction process for elevated viaducts using different methods as well as underground metros using cut-and-cover and top-down construction approaches.
Inspection,Repair and Strengthening of PSC Bridge.Mohammad Furqan
The document provides information on inspection, repair, and strengthening of pre-stressed concrete (PSC) bridges. It discusses common types of deterioration in concrete bridges such as carbonation, chloride attack, alkali-silica reaction, and corrosion of steel reinforcement. It outlines the inspection process including planning, objectives, equipment used, and what elements to inspect such as cracks, bearings, and prestressing components. Non-destructive testing methods like rebound hammer, ultrasonic pulse velocity, and cover meter tests are described. Finally, common repair methods for concrete like mortar filling, grouting, shotcrete, and fiber reinforced polymer wrapping are presented.
This document discusses load standards and the effective width method for bridge engineering according to the Indian Roads Congress (IRC). It outlines various loads that must be considered in bridge design like dead load, live load, impact load, and wind load. It also describes the IRC's standard load classifications for bridges and provides equations for calculating impact percentage and effective slab width. The effective width method per the IRC is described for slabs spanning in one or two directions and cantilever slabs.
The document discusses the basics of social media success. It explains that social media allows for ongoing interactive dialogue through web-based and highly accessible applications. It recommends sharing industry news, expertise, documents, success stories and videos to engage audiences. Additionally, it suggests using platforms like Wordpress to easily update social networks with new content. The key is to lead a tribe of like-minded people by connecting with customers, employees or readers in order to spread ideas widely and persevere with social media over time.
This document discusses Benkelman beam deflection studies, which are used to evaluate the structural capacity of existing pavements and estimate overlay designs for strengthening weak pavements. The Benkelman beam test procedure involves measuring the rebound deflection of a pavement under a standard wheel load. Deflection measurements are taken at intervals along the road using the Benkelman beam and loaded truck. The results are used to calculate the true rebound deflection and characterize pavement strength statistically based on mean, standard deviation, and characteristic deflection values. Overlay design is then determined based on the statistical analysis.
The document discusses methods for stabilizing slopes through terracing or constructing benches. Specifically, it describes:
1) Building benches or flat areas into slopes to break them up into smaller slopes and improve stability. Dimensions of typical benches are mentioned.
2) Modifying the slope geometry, such as through controlled excavation, to redistribute forces and create a more stable configuration.
3) The purpose of benches is to slow water flow, drain water away from slopes, and prevent erosion and scouring that can destabilize slopes. Proper bench design and drainage is important for stability.
This document discusses various methods and standards for measuring pavement surface characteristics like skid resistance and texture. It covers topics like factors that influence skid resistance, methods for measuring micro-texture and macro-texture, standards for measuring polished stone value, and devices for measuring skid resistance at different speeds. The summary provides an overview of the key methods and standards discussed in the document.
This document provides details of Structural Fabrications Ltd, a company that has worked in the water industry for over 15 years. It has worked with several major water companies on various projects. Recently, it was approved by Severn Trent on a 5-year framework for fabrication work. The company serves customers across the UK and provides examples of recent projects it has completed for water treatment plants and pumping stations. These involve installations like lifting gantries, davits, and platforms.
This document discusses tunnel support design in weak rock. It presents concepts for how the rock mass surrounding a tunnel deforms and how support systems act to control deformation. Dimensionless plots show tunnel deformation increases substantially if rock mass strength is less than 20% of the in-situ stress and tunnel closure exceeds 1% of the diameter. A practical example determines support needs for a drainage tunnel based on geotechnical parameters. Steel ribs are selected to generate over 1 MPa of internal support pressure to limit convergence to under 2%.
The document describes the key features of a river diversion arrangement and roller compacted concrete dam for the Jamrani Dam Multipurpose Project. The river diversion includes upstream and downstream cofferdams and a 6.5m diameter tunnel. The 150.6m high RCC dam has a 9km long reservoir and is designed to withstand a probable maximum flood of 8472 cumecs. Stability analyses were conducted considering loads such as earthquake, uplift, and hydrostatic forces, and stresses were found to have adequate factors of safety under all loading conditions.
A casting yard is where concrete structures like segments, parapets, and beams are cast for bridges and viaducts. It must be easily accessible from project sites and have 25-40 acres of land. Concrete elements are cast using long-line or short-line methods, cured, and then transported to worksites. Quality control includes geometry control during casting and testing of concrete slump, setting time, and compressive strength. Precast concrete has higher quality control compared to cast-in-place concrete.
The document discusses the preliminary studies required for the geometric design of roads, including their classification, basic design criteria, engineering considerations, and standards. It covers analyzing demand and terrain, conducting surveys, studying hydrology, geology, environment and safety. The goal is to design roads appropriately based on capacity and standards according to road classification and terrain conditions.
Types of Pavements, Layers present in the pavements, Stresses on the rigid pavements, wheel load, repetitions etc.. and Indian Standard Method of design of Rigid Pavements.
Effect of l b ratio of stone column on bearing capacity and relative settleme...IAEME Publication
This study experimentally analyzed the effect of L/B ratio of stone columns on the bearing capacity and settlement of sandy soil. Model tests were conducted with a square footing and single stone column with L/B ratios of 0.5, 1, 2, 2.5, and 3. The results showed that the minimum relative settlement corresponded to an L/B ratio of 2.5, which also had the highest bearing capacity of 318 kN/m2. Increasing the L/B ratio beyond 2.5 did not significantly improve the bearing capacity. Thus, the optimal L/B ratio for a single stone column was determined to be 2.5 based on minimizing settlement and maximizing capacity.
critical review of extraction of strike longwalls versus dip rise longwall panels in SCCL AP india, operational and planning parametres to be considered for working the same
The document outlines the rules for loads that must be considered in designing and assessing the strength of railway bridges in India. It specifies loads like dead loads, live loads, dynamic effects, wind pressure, seismic forces, temperature effects, and derailment loads. Live loads have increased over time from 18 tonnes per axle in 1903 to 32.5 tonnes per axle currently for the highest class. Dynamic load effects are quantified using a coefficient between 0.15 and 1.0 depending on bridge properties. Seismic forces also depend on the zone the bridge is located in, with zones II-V having increasing seismic specifications.
This document summarizes a student's research poster presentation on redeveloping the shoulder design for an embedded light rail track. The student investigated reasons for deterioration of the concrete shoulders on Dublin's light rail system and proposed alternative solutions. The poster described a case study of a section with deteriorated shoulders. It outlined negatives of the original reinforced concrete slab and concrete shoulder design, and presented a new design replacing the concrete shoulder with asphalt and adding angle brackets to enhance rail stability. Design calculations were provided to show the new design met strength requirements.
The Rion-Antirion Bridge in Greece connects the Peloponnese peninsula to the western mainland via a 2252m long cable-stayed main bridge that spans the Corinth Strait. It was designed to withstand the severe seismic activity and possible fault movements in the area. The main bridge uses four pylons supported by large reinforced soil foundations to distribute seismic forces to the deep weak soil layers. Dynamic analysis showed that during major earthquakes, the reinforced soil and pylon foundations would yield and slide as designed to dissipate energy without compromising the structure. The continuous suspended deck acts as a flexible element that can accommodate displacements without damage. The bridge's innovative design allows all components to work together to resist earthquake forces through
The main outcome of this project is the construction sequence of HMR which primarily starts with excavation, erection of piers, launching girder process and assembling of segments. This project clearly gives a brief knowledge on how the post tensioning and pre stressing works are held at off site and onsite. This project enlightens about the safety requirements and measures taken during the pre-casting works and at on site works.
The document summarizes the design of a 787.8m long flyover with 22 piers and 2 abutments located in Mathura, India. It includes the design of the deck slab, longitudinal and cross girders, piers, and foundations. Pigeaud's and Courbon's methods were used to design the deck slab and girders respectively. Reinforcement details are provided for all elements following Indian design codes. The flyover has a 250mm thick deck slab with 16mm and 12mm bars and 1.575m deep longitudinal girders with 32mm bars. Piers are 2-2.5m in diameter with 28mm or 25mm longitudinal bars. Foundations are 10.
This document summarizes the components, erection procedures, and safety precautions for launching girders used in bridge construction. It describes the main components of launching girders including the main box girder, front support, middle support, and rear support. The erection process is outlined involving assembling the girder, erecting supports, lifting segments, and auto launching. Key safety measures are identified for erection activities and auto launching to control risks like falls, collisions, and structural collapse. A hazard identification and risk assessment is also conducted to rate risks and identify additional safety controls.
The document provides information on various aspects of metro projects, including common terminology used, the different types of metro systems (elevated, underground, on grade), and construction methods. It discusses features of elevated and underground metros such as viaducts, stations, tunnels, and cut-and-cover construction. Diagrams and photos show the construction process for elevated viaducts using different methods as well as underground metros using cut-and-cover and top-down construction approaches.
Inspection,Repair and Strengthening of PSC Bridge.Mohammad Furqan
The document provides information on inspection, repair, and strengthening of pre-stressed concrete (PSC) bridges. It discusses common types of deterioration in concrete bridges such as carbonation, chloride attack, alkali-silica reaction, and corrosion of steel reinforcement. It outlines the inspection process including planning, objectives, equipment used, and what elements to inspect such as cracks, bearings, and prestressing components. Non-destructive testing methods like rebound hammer, ultrasonic pulse velocity, and cover meter tests are described. Finally, common repair methods for concrete like mortar filling, grouting, shotcrete, and fiber reinforced polymer wrapping are presented.
This document discusses load standards and the effective width method for bridge engineering according to the Indian Roads Congress (IRC). It outlines various loads that must be considered in bridge design like dead load, live load, impact load, and wind load. It also describes the IRC's standard load classifications for bridges and provides equations for calculating impact percentage and effective slab width. The effective width method per the IRC is described for slabs spanning in one or two directions and cantilever slabs.
The document discusses the basics of social media success. It explains that social media allows for ongoing interactive dialogue through web-based and highly accessible applications. It recommends sharing industry news, expertise, documents, success stories and videos to engage audiences. Additionally, it suggests using platforms like Wordpress to easily update social networks with new content. The key is to lead a tribe of like-minded people by connecting with customers, employees or readers in order to spread ideas widely and persevere with social media over time.
El documento presenta una tabla de doble entrada que compara las características y ventajas de blogs y wikis como herramientas educativas. La tabla indica que los blogs permiten publicaciones individuales unidireccionales mientras que las wikis facilitan publicaciones grupales bidireccionales de forma práctica y versátil. Ambas herramientas pueden promover el aprendizaje colaborativo y nuevas formas de enseñar y aprender.
El documento describe las características de la capibara, el roedor más grande del mundo. Habita en manadas en zonas húmedas de Sudamérica. Se alimenta de plantas acuáticas y gramíneas ribereñas. Es cazado por su carne y piel. La capibara pesa hasta 50 kg, mide hasta 1,3 m de largo y habita ríos, pantanos y zonas de vegetación densa.
Making use of online resourse for researchNila Shah
The document provides guidance on evaluating online resources for research. It discusses the diversity of online information and need to screen sources based on authority, affiliation, audience level, currency, content, and validity. Specific tips are offered for evaluating each criterion, such as checking an author's qualifications, whether information is factual versus opinion, and signs of carelessness. A variety of subject directories, databases, and journals are also listed as reliable sources for research in languages, literature, and related fields.
This document proposes an academic enrichment program called Aprendamos for elementary school students and their parents. It would use popular education techniques and multimedia projects to teach literacy and integrate with the school's curriculum. Some potential projects include creating timelines with media journals, a neighborhood mapping project using photos and video, and an informational video. The program would run after school once a week and include mini-workshops on multimedia skills as well as project work time. It aims to teach multiple literacies while allowing students to create collaborative, hands-on projects they are proud of.
Project memorandum 91 1313-06 lone star plant water useDuPontEC
This document summarizes a water use study for a sand and gravel processing plant. It finds that:
1) The plant uses about 40 million gallons of water per week, mostly for washing sand and gravel. Current water sources can supply 7 million gallons per week.
2) Water recycling from clarification and dewatering processes can meet most water demands. Additional wells or city connections may provide 200 gallons per minute of backup supply.
3) Simulations found the main water storage tank would not refill without at least 670 gallons per minute of continuous makeup water if no recycling occurred. With 50% gravel and 60% sand pile recycling, the tank refilled with 430 gallons per minute of makeup water
El documento describe las características de la capibara, el roedor más grande del mundo. Habita en manadas en zonas húmedas de Sudamérica, alimentándose de plantas acuáticas y gramíneas ribereñas. Es cazado por su carne y piel. La capibara pesa hasta 50 kg, mide hasta 1,3 m de largo y habita ríos, pantanos y zonas de vegetación densa.
This document provides an overview of sales skills and Monroe Bank's products and services for teller education. It outlines learning objectives focused on identifying customer needs and applying sales skills to suggest appropriate products. It also describes Monroe Bank's checking, savings, credit card, and other banking services. The key terminology section defines important sales concepts like coaching, goals, and customer cues that tellers need to understand.
Managing Existing mineral resources in Indian coal mines-Technological option...MD.Suresh Kumar
Published in SDIMI 2011 fifth international Conference at AACHEAN UNIVERSITY, GERMANY.( Sustainable Development in the minerals Industry) by MD.SURESH KUMAR from SCCL, INDIA.
Ground control continues to be a crucial issue in Indian coal mines ..What we...MD.Suresh Kumar
Published in international conference on strata control at NIT, Rourkhele authored by B.Ramesh kumar Dir(PP) and MD.Suresh Kumar Addl mgr/Col Mgr of SCCL, India
or:
1) The document describes issues with roof guttering encountered during underground coal mining in India and efforts to address it.
2) Roof guttering was causing instability that required additional roof support and slowed production. Various techniques were tried to stabilize the roof, including advanced roof bolting with longer bolts installed at an angle.
3) Monitoring bolt performance and hydraulics, along with adjusting the bolting process, reduced guttering and improved roof conditions and production rates.
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El documento presenta información sobre el capibara, el roedor de mayor tamaño del mundo. Habita en manadas en sabanas, ríos y pantanos de Sudamérica, especialmente en las cuencas del Amazonas y el Paraná. Se alimenta de plantas acuáticas y gramíneas ribereñas. Es cazado por su carne y piel.
El documento describe las características de la capibara, el roedor más grande del mundo. Habita en manadas en zonas húmedas de Sudamérica, alimentándose de plantas acuáticas y gramíneas ribereñas. Es cazado por su carne y piel. La capibara pesa hasta 50 kg, mide hasta 1,3 m de largo y habita ríos, pantanos y zonas de vegetación densa.
Los principales recursos naturales de SulTePeC incluyen áreas de pinos y oyamel, áreas verdes de la escuela preparatoria, bancos de cantarita morada, rosa y verde, y minas de plata no explotadas. El documento hace un llamado a cuidar el medio ambiente de SulTePeC y promueve el eslogan "SulTePeC ¡Con encanto!".
The document provides information about social media and digital marketing strategies. It discusses which social network has the most users in the UK (Facebook), when Facebook launched (May 2006), and which location-based marketing service is most prevalent in the UK (Facebook). It also mentions that Facebook launched a deals product in January and that over 80% of new UK mobile contracts in the last quarter of 2010 were for smartphones. The document emphasizes measuring strategies, having a clear strategy and call to action, and considering your customer database and data segmentation when developing a digital plan. It states that a company website is still the bedrock for marketing a business and social media conversations can be difficult to control.
This document discusses the design of pillars in underground coal mining. It notes that pillar failure can be either gradual or sudden, with sudden failures causing disasters. Statutory guidelines for pillar dimensions are provided but have limitations as mine depths increase. The author proposes modifications to the standard formula for calculating rock load on pillars to account for dynamic loads during pillar extraction, with a dynamic load factor. Two common formulas for estimating pillar strength are examined, with the author noting limitations and suggesting greater consideration of pillar width in the calculations. Overall, the author aims to provide a more scientifically-based approach to pillar design for stability during formation and extraction.
This document discusses the design of pillars in underground coal mining. It notes that pillar failure can be either gradual or sudden, with sudden failures causing disasters. Statutory guidelines for pillar dimensions are provided but have limitations as mine depths increase. The author proposes modifications to the standard formula for calculating rock load on pillars to account for dynamic loads during pillar extraction, with a dynamic load factor. Two common formulas for estimating pillar strength are examined, with the author noting limitations and making suggestions to better account for depth and pillar width factors. Overall, the author aims to provide a more scientifically-based approach to pillar design for stability during formation and extraction.
This document summarizes the experience of dynamic loading and strata control problems faced during longwall mining with a sandstone roof at the Padmavathikhani mine in India. The 11th panel had a sandstone roof which caused major issues. During retreat of the longwall face by 40.6 meters, a large main fall occurred over an area of 6,957 square meters. Ninety hydraulic legs on the powered roof supports experienced pressure increases up to the yield pressure of 38.7 MPa during this weighting event. Intense strata monitoring was carried out to study the loading behavior and caving of different rock layers.
Retrofitting the well foundation of a railway bridge subjected to scourSushil Dhungana
This document discusses retrofitting techniques for strengthening the well foundation of a railway bridge subjected to scour. It proposes two retrofitting methods: 1) Installing piles around the well foundation, but finds this would not fully transfer loads or relieve pressure. 2) Creating a shallow foundation around the well to partly transfer vertical loads, all moments, and protect against scour in the top 2.5-3m. Analysis shows bearing pressure is within capacity even for increased modern loading standards. The revised approach of a reinforced concrete ring foundation is suggested to strengthen the existing well foundation against failure due to bending stresses or scour.
- The design of pillars is a critical aspect of underground pillar mining to ensure strata control and prevent sudden, catastrophic pillar collapses.
- Statutory guidelines exist for pillar dimensions but have limitations as they are based only on past experience and do not consider dynamic loading or scientific analysis.
- The author suggests a modified formula for calculating pillar load that includes a dynamic load factor to account for loads during pillar extraction, which are different depending on the extraction method.
Pile&Wellfoundation_ManualUpdated as on 20.5.16.pdfDharmPalJangra1
This document provides guidelines for the design and construction of well and pile foundations for railway bridges in India. It covers topics such as the depth of well foundations, shapes and cross-sections of wells, allowable bearing pressures, types of pile foundations, pile spacing, and load carrying capacity of piles. The guidelines are intended to help transfer heavy bridge loads to deep soil strata in a safe and stable manner. Standards are provided for various aspects of well and pile foundation design to suit local soil and construction conditions in India.
This document discusses consolidation of soils. It defines effective stress as the difference between total stress and pore water pressure. It describes the analogy of soil skeleton to a piston and spring system. It presents calculations for consolidation settlement, coefficient of consolidation, coefficient of compressibility, and permeability. It discusses preconsolidation stress, typical values, and expansive soils. In conclusion, it summarizes that soil compression occurs during drainage and drainage must be considered for structures like embankments to ensure proper consolidation and settlement.
This document discusses consolidation of soils. It defines effective stress as the difference between total stress and pore water pressure. It describes the analogy of soil skeleton to a piston and spring system. It presents calculations for consolidation settlement, coefficient of consolidation, coefficient of compressibility, preconsolidation pressure, and degree of consolidation. It discusses typical values for consolidation parameters in clays and organic soils. It also describes the expansive behavior of some soils when water content increases or decreases.
The document discusses blasting operations carried out at the Ramagundam Thermal Power Station in India to excavate rock as part of an expansion project. Blasting was required near sensitive existing infrastructure like generators and transformers. Careful planning was needed to limit ground vibrations and prevent flyrock. Through trial blasts, parameters were established for burden, spacing, stemming, and initiation timing. Blasting progressed from areas farther from critical infrastructure toward them. Methods like changing blast direction and using soil and covering mats helped restrict flyrock and vibrations near the edge of blasts closest to generators. Blasting for footings also required high stemming and covering density to minimize flyrock risks to nearby structures. The successful blasts achieved required
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The document summarizes the design and construction of the foundations for the Rion Antirion Bridge in Greece. Key points:
- The foundations had to withstand severe environmental conditions like weak soil, earthquakes, and tectonic movements. An innovative concept was adopted using large diameter caissons resting on reinforced natural ground with steel pipe inclusions.
- Under each caisson, 150-200 steel pipe inclusions 2m in diameter were driven into the soil in a 7m grid to reinforce it. A 2.8m thick gravel layer separated the caisson from the inclusions.
- This concept provided capacity design by allowing sliding at the gravel interface during large seismic forces, limiting forces on the super
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3) Housel's method involves conducting two plate load tests and solving equations involving load, plate area and perimeter to determine constants, which are then used to calculate load and size of a prototype foundation that results in the permissible settlement.
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The document discusses the design of pillars in underground coal mining. It notes that pillar failure can be gradual or sudden, with sudden failures causing disasters. Statutory guidelines exist for pillar dimensions but have limitations. The author proposes a modified formula to calculate pillar load that includes a dynamic load factor to account for loads during pillar extraction. Pillar strength is typically estimated using empirical formulas that the author critiques. The author suggests experience and site conditions be considered to better estimate pillar strength for ensuring stability of underground workings.
#تواصل_تطوير
المحاضرة رقم 187
أستاذ دكتور / مدحت كمال عبدالله
عنوان المحاضرة:
تدعيم كباري باستخدام التفاعل المشترك
للمياه - جسم الكوبري
وعرض حالة عملية
Temporary Support Of Existing Bridges Using
Water-Structure Interaction
including case study
يوم الإثنين 26 ديسمبر 2022
الثامنة مساء توقيت القاهرة
التاسعة مساء توقيت مكة المكرمة
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Support system (Underground Coal Mining) by Prof. S Jayantu.pdfpraanyakishore
This document provides details on a case study to design support systems for an underground coal mine. It describes the geomining conditions, including coal seam thicknesses and depths. It then outlines the design of support systems for various areas of the mine, including galleries, junctions, slices during depillaring, goaf edges, and gallery sides. Support designs are based on calculations of expected rock loads using methods like the Rock Mass Rating (RMR) system and NGI-Q system. Designed support systems include fully grouted roof bolts, wooden lagging, steel props, and wire meshing. The objectives are to systematically extract pillars while maintaining safe conditions underground.
The Rion Antirion bridge in Greece connects the Peloponnese peninsula to the mainland across the Gulf of Corinth. Its foundations had to withstand severe environmental conditions including weak soils, earthquakes up to magnitude 7.0, and long-term tectonic movements. The innovative foundation concept adopted reinforced the natural ground with steel tubular piles and included a gravel layer between the piles and foundation raft. This provided capacity to resist the large seismic forces while minimizing differential settlement hazards. Extensive site investigations characterized the poor soil properties to ensure compatible design of seismic demand and foundation capacity.
1. Soil investigations are conducted to obtain information useful for planning, designing and executing construction projects. This includes determining soil properties, groundwater levels, suitable foundation types and depths, bearing capacity, settlements, and lateral earth pressures.
2. Standard penetration tests are used to determine soil properties like relative density and strength. The test involves driving a split spoon sampler into the soil using a hammer and measuring the blow counts. Corrections are made for dilatancy and overburden pressure.
3. Piles can be classified based on material, load transfer method, construction method, use, and soil displacement. Components of a well foundation include the cutting edge, well curb, stining, bottom plug, sand fill
The Cambay #15 well has experienced 100% water cut due to excess water production. To address this, a squeeze cement job will be performed to seal off the existing open interval between 1400-1404.5m. Cement will be squeezed into this zone and the tubing shoe adjusted upwards to 1395m to perforate a new production zone higher in the formation, transferring production to upper sands with the aim of resuming oil production.
Similar to An experience of Loading pattern on Power supports with Sand stone roof in SCCL (20)
This document summarizes the experience of working Longwall Panel No. 8 under adverse strata conditions at Kothagudem Colliery. Key challenges included:
1) A steep 1 in 4 face gradient that caused support and equipment issues.
2) Encountering a dyke in the coal seam that weakened the coal.
3) Heavy water inflows from overlying mine goaves and a seasonal stream.
Various techniques were employed to address these challenges, such as reducing the face length, controlling creep, and using mesh supports around the dyke.
1. Underground coal mining in India faces challenges in meeting growing energy demands due to reliance on open pit mining which has environmental issues. Proper exploitation of existing underground resources is needed using suitable technologies.
2. India has large coal reserves but most production currently comes from open pit mines. New longwall mining technology could help extract more coal underground from thick seams.
3. Extraction of coal pillars left behind in underground mines and use of shortwall mining could help bridge future supply gaps if challenges around complex geology and support systems are addressed.
State of art of Mechanisation of Underground minesMD.Suresh Kumar
1. The document discusses the future challenges facing SCCL including depleting opencast reserves and the need to mine deeper underground reserves.
2. Longwall mining is presented as a technology that can enable bulk underground coal production safely and with higher recovery rates compared to other methods.
3. Key advantages of longwall mining discussed include proven success in thin and thick seams, improved safety, and potential for ongoing technological developments and automation.
1.5MT Longwall faces in SCCL-Few planning issuesMD.Suresh Kumar
fThis paper was presented in MGMI Kothagudem chapter. This maily deals with various options for mechanisation od underground mines and their merits and demerits. The various advantages of Longwall technology and its supremacy in the different geo-mining conditions.
This Technical paper on “Experience of strata monitoring studies in a shallow depth Long wall extraction by caving in panels 1&1A of PVK-5 Incline” was presented at 3rd National Seminar on Rock Excavation Technique at Nagpur.
An experience of Loading pattern on Power supports with Sand stone roof in SCCL
1. AN EXPERIENCE OF LOADING PATTERN ON POWER SUPPORTS
WITH SAND STONE ROOF IN SCCL
M. S. VENKATA RAMAIAH MD. SURESH KUMAR
Dy. General Manager Addl. Manager,
THE SINGARENI COLLIERIES COMPANY LIMITED. INDIA.
1. INTRODUCTION:
Padmavathikhani-No.5 Incline is one of the important mines of SCCL. Mechanized longwall
mining has started in 1995. 11 longwall panels have been completed and the 12the panel is
under extraction. These longwall panels were worked with 4 x 760 Te supports, the details of
which are given in Annexure I.
Longwall mining in PVK was operated in middle section of the Top seam. The contact roof
was shaley coal roof, which collapsed with the advance of the support in the goaf without any
overhang. Contrary to the above, the longwall panel No.21, which is the 11th panel was
worked with contact roof of sand stone.
The present paper deals with the loading pattern of 4x760 Te supports and the measures
taken to complete the panel No. 21. In future SCCL is planning to work longwall panels with
stone roof. The present experience can be utilized for formulating the guidelines for future.
2. DETAILS OF LONGWALL PANEL NO.21:
Long wall panel No.21 has been worked in Top seam at a depth of 206m and 239m with a
face length of 150m and the panel length of 420m. The face was worked partly with contact
roof of stone and partly with shaley coal roof because of the local geological disturbances.
3. LITHOLOGY OF THE OVERLYING STRATA:
The lithology of the overlying strata was studied in detail for calculation of the cavability
index. Borehole No. A/336 has been specially drilled to delineate the bed Inclines. The data
of this bore hole was utilized for installation of Multi Point Bore Hole Extensometer and
numerical modelling by CMRI. The borehole data is given in Annexure-II.
4. STRATA MONITORING IN PANEL NO. 21
The strata monitoring plan for panel No.21 has been prepared in which various instruments
were installed, the details of which are given in Annexure-III.
5. PREVIOUS EXPERIENCE IN PADMAVATHIKHANI:
A review of the earlier experiences of loading pattern is summarized below:
2. Loading Patten on Power Supports 2
1. The panels were worked in middle section of 9m thick Top seam.
2. The immediate roof comprising of 3m shaley and shaley clay has collapsed in th goaf as
soon as the supports were advanced.
3. Closure of supports which hinders the movement of shearer has never occurred earlier.
4. The main fall occurred after 6000 to 7000 m2
exposure.
5. The periodic weightings occurred at 15 to 20m face advance.
6. Load on the four legs were not uniform. Front legs were more loaded than rear legs.
6. OPERATION OF THE FACE WITH CONTACT STONE ROOF IN
PANEL NO.21
The panel started with contact roof with sand stone, which continued for the length of 360 m
and ended with coal roof in the last 60m. Initially, the first local fall occurred at the face
retreat of 20.85m where sand stone roof up to the height of 3.0m (bed 1 & 2) collapsed.
Successively, the collapse extended throughout the face in three stages. Leg pressure
increased to 30.0MPa. Then the intermediate beds (bed 3 & 4) collapsed exerting pressure up
to 32.0MPa over the supports.
The main fall and periodic falls were experienced with total contact roof of sand stone; the
details of local fall, main fall and subsequent periodic weighting are given in the table.
DATE WEIGHTING
AVERAG
E FACE
RETREA
T (M)
INTE-
RVAL
WEIGHTING
ZONE
LEG
PRESSURE
RANGE
NO. OF
LEGS
ATTAINED
YIELDING
PRESSURE
AREA OF
EXPOSUR
E
(SQ.M)
27.08.04 LOCAL FALL 20.85 TG to C-60,
C-60 to C-30,
C-30 to MG
28-30 Mpa 3,832
06.09.04 MAJOR
FALL
37.4 C-30 to C-70 29-32 MPa 6,396
07.9.04 MAIN 40.6 40.6 C-14 to C-81 28-37.8MPa 92 6,957
12.9.04 P.W.- I 49.6 9.0 C-38 to C-39
C-65 to C-69
28-37.8MPa 1 8,200
18.9.04 P.W - II 60.0 11.0 C-27 to C-64
C-72 to C-100
28-37.8MPa 1 9,900
During main weighting 90 legs have undergone bleeding and almost all the supports got
loaded throughout the face. Out of 90, 45 were front and 45 were rear legs. The mean load
density during main weighting and periodic weighting has been calculated for the total face,
which are given the following figures.
MG – 25 25 – 50 50 – 75 75 – TG
80.4 90.19 71.75 69.02
3. Loading Patten on Power Supports 3
Convergence Data
o 39mm cumulative convergence at 2m ahead of the face in tail gate.
(12mm per day in the day of weighting at this Point.)
o 23mm cumulative convergence at 7m ahead of the face in tailgate.
(8mm per day in the day of weighting in this Point.)
o 18mm cumulative convergence at 12m ahead of the face in tail gate.
o 9mm cumulative convergence at 22m ahead of the face in tail gate.
7.0 PROBLEMS FACED DURING 3RD
PERIOD WEIGHTING:
♦ During third periodic weighting at the face retreat of 67.0 m the face had undergone
severe dynamic weighting. The power supports experienced heavy leg closures and
♦ Around 25 supports from c-60 to c-90 become solid towards tailgate side.
♦ The shearer could not be moved which was trapped on other end.
4. Loading Patten on Power Supports 4
♦ The face become stand-still, it took around 15 days to restore the normal operation
with lifting the power supports one by one by blasting off sand stone roof from
underground itself.
8.0 THE VARIOUS REASONS ATTRIBUTED to such dynamic
loading and severe leg closures.
On careful assessment the following are the various reasons brought to height with the
concrete basis.
A. Standing goaf
B. Reduced hydraulic run in the pistons
C. Premature Bleed valves
D. Slow rate of retreat.
A.STANDING GOAF
The zone where the supports experienced dynamic loading had a unbroken, Solid, cantilever
sandstone roof extending into goaf for a length of 20 m. Normally the immediate sand stone
beds Bed 1&2 having RQD 44-93 caving index of 175-1690 and thickness 1.3m-4.0m
respectively found collapsing regularly behind the supports leaving only 1-2 m overhang.
Thereby the collapse of beds 1&2 used to open a room to the upper beds to converge readily.
But for no reason, this immediate roof held a long cantilever in this particular zone for a
length of 50m in the direction along the face. Whereas it collapsed up to rear shield in the
other part of face .The reasons may be
• Change in Weight modulus of elasticity of the rock and
• Change in the Petrography of rock formation, which would have increased the value of
RQD and massiveness locally.
Hence, the 20 m overhang of Bed 1&2 prevented the collapse of upper beds -Bed 3, 4 & 5
atleast for a length twice of its span of overhang ie.,40 m which started exerting enormous
stress over the supports.
5. Loading Patten on Power Supports 5
• Therefore the Dynamism of load transfer had been initiated during the course of failure
of rock mass of all the
beds Bed1+Bed2+Bed3+Bed4+Bed5 simultaneously.
• The presence of 2.0m thick clay band (bed6) is the one more responsible to cause sudden
release of rock mass in total.
• Which in turn closed around 25 supports and become rigid.
The intensity of load in the other part of the face within the weighting zone was relatively
less where the goaf overhang is less than 2.0m which is compared below:
DESCRIPTION C 60 TO C90 OTHER PART IN THE WEIGHTING ZONE
Leg closure 400mm-600mm 2mm-10mm
No.of legs bleeding 100 55
Goaf overhang 20.0m 1-2m
Leg pressures Almost all bleed pressure 28-32Mpa
B.REDUCED HYDRAULIC RUN OF THE PISTONS
Due to minor up-throw and down-throw faults in the face, the piston heights were reduced to
500mm in the weighting zone of c60-c90 to have uniformity in the floor horizon. The same
6. Loading Patten on Power Supports 6
situation was continuing for one week before the start of weighting. The reduced run of
pistons eventually led to leg closure at faster rate that it did not give any allowance to move
the face ahead during the time of Collapse of total strata mass.
C. PREMATURE BLEED VALVES
The bleed valves are of spring loaded mechanical type having rate of delivery of fluid 60 lit
per min. These bleed valves were being regularly checked in underground and brought to
surface for calibration and testing at approved test bench at under ground machine mining
work shop R.G II Area SCCL.
On careful verification it was revealed that in the zone of dynamic load transfer (c-60 to c-90)
around 70 Nos. of bleed valves started bleeding below the set pressure of 38.7Mpa (i.e.30 to
34Mpa) which in turn reduced the support resistance enormously.
DATE WEIGHTING
ZONE
PRS BECOME
SOLID
NO. LEGS
ATTN.BLEED
PRESSURE
NO. OF BLEED
VALVES
PREMATURE
23.9.04 C-43 to C-98 No support become
solid
11 70
24.9.04 C-29 to C-98 C-60to90 22 49
D.SLOW RATE OF RETREAT
Due to some equipment break down, the face down time was increased during this particular
period. An average of 2.5m per day was maintained upto main fall with which the face could
able to be retreated without any such strata control problems. The details of face progress is
listed below:
7. Loading Patten on Power Supports 7
DATE NUMBER
OF SHEARS
TOTAL
SHEAR
S
AVG.
RETREAT
(M)
REASONS FOR FACE SLOW RETREAT
I II III I SHIFT II SHIFT III SHIFT
21.9.04 0.5 1 2.5 4 1.9 Power off Power problem
Track bar welding
Main belt
BSL pan
set broken
22.9.04 0.5 1.5 Nil 2 1.1 AFC Gear box
Motor
transport
Trunk belt
problem
Trunk belt
problem
23.9.04 0.5 2.5 0.5 3.5 1.4 Trunk
belt problem
Coal evacuation
problem at
Surface Bunker
Trunk belt
problem.
24.9.04 Nil 1.5 1 2.5 1.5 Shearer
problem
Coal evacuation
problem at
Surface Bunker
25 supports
solid
9. MEASURES TAKEN TO OVER COME
Though there were three Borehole lithologs so closely located at the centre of this panel to
assess the rock formation, it has got only less scope to predict homogeneous formation of
rock mass. Hence variation is expected within the panel also. Borehole lithology can not be
taken for granted solely.
More over it cannot be possible to retreat the face at guaranteed faster rate of retreat due to
aging of equipments and other constraints. Then it was decided to attempt
♦ Induced blasting from underground and to avoid any chances of goaf overhang.
♦ To maintain the hydraulic run of PRS to 0.8 to 1.0m at any cost
10. INDUCED BLASTING
Almost in the every maintenance shift induced blasting was done in the face. Invariably the
goaf over hang was monitored regularly Wherever the cantilever span exceeds by 5.0m the
blasting was resorted in that particular zone. The details of induced blasting is given in
Annexure – IV.
11. HYDRAULIC RUN
Apart from induced blasting, it was holistically decided to maintain the hydraulic run of
power supports in range of 0.8 to 1.0m at any given time of face retreat. Hence,
• Whenever small up-throw and down throw faults encountered in the
face ,was blasted off to maintain the hydraulic run.
• Also it was cut with shearer to have correct horizon without bothering the consumption of
picks.
• Some times the floor horizon got lifted up thereby the total height in the face was reduced
due improper floor cutting. The operators thoroughly educated and with the dedicated
approach it was monitored round the clock.
8. Loading Patten on Power Supports 8
12. NUMERICAL MODELING AND COMPARISON WITH FIELD
STUDIES
Numerical modelling has been done by CMRI for this panel. After the conducting of field
studies, the data has been compared with the predicted numerical modeling data, the details
of which are given below:
DESCRIPTION MODELING PREDICTION ACTUAL
First Local Fall 28.0m 24.6 m
First Major Fall 36.0m 41.40 m
Main Fall 48.0m 44.60 m
13. CONCLUSION
The experience of working longwall panel No.21 with stone roof has generated lot of
experiences. Some of the important experiences are as follows:
1. Strata monitoring studies have to be conducted exclusively so as to maintain the
equipment accordingly.
2. The intensity of loading in contact stone roof is high compared to coal roof.
3. All the four legs were loaded uniformly in stone roof.
4. Closure of supports with high convergence hinders the movement of the shearer.
Hence, the hydraulic run should be carefully monitored and maintained.
5. Induced blasting is necessary to fill the goaf with caved material so as to reduce the
intensity of dynamic loading and air blast.
6. During the time of weighting, face has to be worked with higher rate of retreat
7. The hydraulics including valves, bleed valves and legs should be maintained properly
to operate the supports at designed capacity.
14. RECOMMENDATIONS:
The experience for working longwall panel No.21 with stone roof can be further disseminated
for formulating the guidelines for working longwall with contact roof of stone roof. The
apprehension that longwall can work only with shaley coaly roof is no more valid. It is
recommended that further study based on numerical modelling calibrated with the above
experiences can be utilized for working longwall with hard stone roof like King seam of
Kothagudem Area and No. III seam of Godavarikhani area.
In Padmavathikhani project report longwall mining has to be continued in contact roof of
stone. Similarly, it is also proposed to work longwall in the above conditions of No.III seam.
15. ACKNOWLEDGMENTS:
The authors expressed their gratitude to the management S.C.Co.Ltd., for giving permission
to publish the above paper. The views expressed in this paper are of their own and not
belonging to the organization in which they are working.
10. Loading Patten on Power Supports 10
ANNEXURE -II. BOREHOLE DATA
Three boreholes drilled from surface
for the purpose of monitoring of
caving of different rock beds using
Multi point borehole Extensometer
at the center of the panel
30,60,175m from the face start
line.The different composite
rockbeds have been studied by
CMRI and Mine management
carefully.The cavablity of different
rock beds has been calculated using
the following empirical relationship.
I = CLn
t0.5
5
Where
I = cavability index
C=Compressive strength kg/cm2
N = constant depending on RQD%
L = avg.length of core in cms
T = thickness of bed in m
Based on cavablity index and the
RQD,the
• Immediate roof -bed 1&2
• Intermediate roof -bed 3&4
• Massive and main roof -bed 5
• Parting plane -bed 6 of clay
band
Were delineated and
distinguished.The rock formation
encountered in all the three
boreholes found to be holding
similarity in terms of RQD and
caving
index.
Borehole No A/336
DEPTH FROM
SURFACE (M)
BED
NO.
HEIGHT ABOVE
COAL SEAM, M
LITHOLOGY
BED
THICK
NESS
(M )
RQD
(%)
AVG.
LENGTH
OF
CORE
(CM.)
COMPRESSIVE
STRENGTH
KG/CM
2
CAVING INDEX
FROM TO FROM TO AVG. MAX. AVG. MAX
COAL SEAM
211 212.3 BED-1 0 1.3 CG SST, GW, 1.3 44 8.67 89 101 175 199
207 211 BED-2 1.3 5.3
CG SST, GW,
PEBBLE
4 93 24.3 92 104 1690 1910
203.3 207 BED-3 5.3 9
CG SST, GW,
PEBBLE
3.7 77 13.7 89 101 792 898
196.8 203.3 BED-4 9
15.5
3
CG TO FG SST 6.53 94 19.2 98 110 1736 1945
184.3 196.8 BED-5 15.5
28.0
2
CG SST, GW,
PEBBLE
12.5 78 16.6 92 104 1893 2140
182.3 184.3 BED-6 28.0
30.0
2
GREY AND
CARB.CLAY
2 - - - - - -
12. 12
ANNEXURE –IV INDUCED BLASTING
A) Location of blasting
• More emphasis was given to blast in
mid face c-40 to c-60.
• The over hang of less than 5.0m was
also blasted during periodic
weighting
Time
• The zone where, if by any chance the
piston height is reduced, the goaf in
the rear legs was induced.
B) Method of blasting
• Around 3-4 m shot holes were drilled
and blasted in bed 1&2 at 45º angle
between the gaps of power supports,
near rear legs without allowing men
onto goaf
• Initially a hydraulic drill was
tried.But due to constraints in
accommodating the machine in the
face, manual drilling was done with
electric drills
• The 3-4 deep shot hole was drilled
with special drill rods.
• Charging was done by using plastic
spacers
• Only P1-explosives with
instantaneous electric detonators were
used in the shot holes.
• Atleast 15-20 shot holes (say for
example c40-c55) used to be blasted
in the maintenance shift without
affecting the production shifts by an
experienced shotfirer.
• Again in the next day blasting used to
be carried out from c56 –c70 in a step
pattern by that time face was
retreated to new position if the sand
stone overhang extended upto c70.
• But during face weighting, it was
arranged to blast the entire length of
overhang even by affecting the
production.
• Depending upon the necessity and
length of overhang along the face,
there used to be two drilling gang,
one from main gate side other from
tailgate side because the drilling
operation was only the critical and
time consuming.
• But only one shot firer used to blast
13. 13
all shot holes. If the immediate stone
bed did not break at the first day of
blasting, attempts were made to blast
the same zone on the next day in the
new position of the face.
C) Effect of induced blasting
• As the induced blasting was practiced
mainly to break the immediate roof it
was noticed that some times it had
readily broken and a groove was cut
to the depth of 1-2 m .
• But many times the blasting effect
could not be able to break the roof.
But it shattered the strata thereby
cracks were developed and
• During the time of upper beds and the
main bed started deflecting with load
transmitted over the supports, water
started dripping from the cracks of
blasted zone and the immediate beds
used to break readily.
• Thereby the plane of weakness was
created exactly at the induced break
line.
• Once the immediate beds collapsed,
the upper beds used to deflect from
the higher origin which exerted only
nominal load over the supports
• Moreover the rate of leg closures was
reduced drastically as the upper beds
lost its direct cantilever action over
the support canopies.
References:
1. Mathur S.P.,(2003) " Strata control - practical considerations" Coal mining technical
and management. Vol.10, Nov'03.
2. Dr.Samir Kumar Das (2004), “Design of Powered Supports for Longwall Faces”, In
house short term course for Mining Executives, 18-23 April 2004.
3. Venkata Ramaiah M.S. and Suresh Kumar M.D., (2004) "Experience of Strata
monitoring studies in shallow depth longwall extraction by caving in Panel no. 1A &
1 of PVK-5 Incline" 3rd
National seminar on rock excavation techniques at Nagpur
organised by The Indian Mining and Engineering Journal Bhubaneswar chapter.
4. Suresh Kumar M.D., and U.Shiva shankar (2006)”
Need for working longwall
under hard roof in future underground mining-An experience of negotiating main
weighting in sand stone roof”-workshop on future of underground coal mining in
india mechanised board&pillar or longwall”organised by JMMF.Kolkata.
5. Report on "Numerical modeling & Strata and support behaviour investigations at
panel 21 PVK-5 incline", Dec'04.