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Underground surge pool cavern for the storage and lifting of water is being constructed in the part of Telangana State of India. For better rock mass characterization and support design, 3D engineering geological mapping was carried for the heading portion of the surge pool. 3D geologic mapping of heading portion is very important for large underground cavern to know about the cavern behavior during benching down. The direction of the longest axis of the cavern was finalized based on the in-situ hydrofracturing testing inside the deep borehole. The assessment of tunnel quality index 'Q' for the exposed granitic rock mass was done based on the information available of the rock joints and their nature, 3D geological mapping and in-situ stress measurement. Roof support and wall support pressure was estimatedbased on Q-values, and in this case applicable for the non-squeezing ground condition. For structural stability of crown and walls, rock support arrangement was recommended based on NMT technology and geological conditions of site, which includes steel fibre reinforced shotcrete, grouting, rock bolt and drainage hole provisions. The capacity of support system is determined to evaluate the efficacy of the proposed support system. [ABSTRACT FROM AUTHOR]

The longwall method is one of the feasible and efficient underground mining methods for greater depth of workings. Recently, Singareni Collieries Company Limited (SCCL), the largest coal-producing government company in the Southern part of India, has deployed a high capacity (2 - 1152T capacity) power support system in its Adriyala Longwall Project (ALP) at a depth of 375 m. There was a concern about the stability of the longwall workings and the protective pillars. Thus, research work was carried out with the geotechnical instruments and numerical modelling tools to analyze the stability while retreating the longwall panels. The outcomes revealed that the convergence in the gate roads increased with the longwall face advancement and the area of exposure. The pressure of the powered support legs on the dip side was less than the rise side legs, which implies a stable roof condition over the longwall face. An abutment zone was identified ahead of the line of extraction up to 10e25 m and presumed from the Factor of Safety (FoS) criterion that within this zone, the longwall pillar possibly will be of better stability at every stage of extraction. The results obtained from this study would be helpful for the mining engineers to understand the behaviour of underground strata in longwall workings. [ABSTRACT FROM AUTHOR]

The documentation of excavation method and support design based on rock mass classification systems i.e. rock mass rating (RMR), Q-system and New Austrian tunneling method (NATM) for adit-7 tunnel being constructed in Garhwal Himalaya, India is discussed in this paper. The New Austrian tunneling method classes of rock units have been developed by using correlations with the RMR and Q systems, according to the ONORM B 2203. NATM principles were used because the geological conditions were continually changing. The study indicated that the RMR-based rock mass estimation was overstated, but the qualitative assessment was right. The NATM technique is more adaptable for Garhwal Himalayan rocks having various uncertainties in rock mass evaluation. The current adit investigations indicate that there are numerous unanswered concerns, concerning rock mass quality evaluation, tunnel behavior during construction and usability. Results of the analysis are considered to be useful for the design of the new tunnels constructed in the similar type of the terrain. [ABSTRACT FROM AUTHOR]

Storage of crude oil and other petroleum products in unlined caverns is a well-proven technique, with successful implementation in many parts of the world. The Government of India started the construction of underground crude oil caverns in 2008 to store 5.33 million metric tonnes (MMT) of imported crude oil in three crude reserves, based on a 15-day crude oil requirement in all the Indian refineries. Underground storage of hydrocarbons is not only more secure, safe and economical than above-ground storage, but also has several environmental and operational advantages. The construction of an underground storage requires a large excavation within a short period. Typical construction schedule for 1.0 MMT storage is around 30 months for excavation and support and another 6 months for laying underground concrete and processing. This tight construction schedule requires careful planning, deployment of necessary equipment and qualified manpower and strict adherence to all quality and safety procedures. In this article, an attempt has been made to highlight the need for underground crude oil storage, principle of storage, types of investigations required to test for feasibility, detailed project report and construction stages, the requirement of geological, geohydrological and geotechnical models for engineering and design, construction methodology and geotechnical and geohydrological monitoring required during the construction and post-construction phase of the project based on the author's association with three projects. [ABSTRACT FROM AUTHOR]

The nation’s standard of living depends on its quantum of production and use of natural resources, including coal. Coal plays a major role in the development of a country like India. India has great potential of producing coal economically. Unfortunately, even after the nationalisation of 50 years of major Indian coal mines, we still have lower productivity than other coal-producing countries. The Indian mining industry has improved productivity in the opencast sector, but unfortunately, the industry still has to improve productivity in the underground sector. The underground coal is more free from any dirt, which is more acceptable for the user. If the underground productivity of the Indian coal industry is seen, it is the lowest compared to the countries producing coal. Initially, the industry thought of using the longwall technology but could not succeed of its limitations. For the last 20 years, the underground coal mines have been experiencing continuous miner who is not very expensive (as in the case of Longwall), not requiring the major restructuring of the old structures, having good productivity and more safety in operation. This paper deals with continuous miners and their success in the bord and pillar method. [ABSTRACT FROM AUTHOR]

The entire Himalayan arc is predicted to produce a series of significant earthquakes and the subsequent great earthquakes of magnitude 8.0 and higher. A substantial amount of rock tunneling is being carried out in the Himalayan region to meet the growing demand for transportation, power, and other infrastructure projects. Earthquake forces influence the final design of the tunnel, which requires further strengthening of the concrete lining and improvement in tunnel support. Because of increasing importance, it is essential to combine the dynamic forces and displacements produced by seismic ground movements into the design stage for tunnels. In this paper, a numerical analysis has been carried out to assess the seismic performance of a proposed hydropower tunnel of 8.8m diameter (horseshoe-shape) in Uttarakhand, India. The impact of earthquakes on underground structures such as tunnels is often considered to be insignificant. However, the results of this study show how that stress from seismic loads can be damaging to the stability of the tunnel. In this study, a pseudo-static approach was adopted to assess the impact of the earthquake on the tunnel lining for the sections located in different rocks namely slate (Q=3.4), quartzite (Q=6), and dolomitic limestone (Q=5.2), respectively. Pseudo-static analysis findings suggest there is a 35% increase in the lining forces for an impact of earthquake for the tunnel section situated in Slate. Furthermore, displacements and damage-prone areas are determined to assess the damage to the tunnel, which could be helpful for rapid evaluations of potential future damage. [ABSTRACT FROM AUTHOR]

Slope failures are recurrent phenomena during the Indian Summer Monsoon (ISM) season in the mountainous regions of Arunachal Himalaya, NE India, with a consequent damaging impact on the landscape, life, and property of the people. Geodynamic conditions, fragile lithology, high magnitude seismicity together with high-intensity rainfall from ISM provide the potent mixture of conducive factors contributing towards a very high frequency of landslides in the region. The problem is further accentuated by anthropogenic activities that have increased in recent times. Here we present a case study of a vulnerable road segment between Doimukh and Haj along the National Highway (NH-229) in Papum Pare district of Arunachal Pradesh that witnesses recurring debris slides during the rainy season. We suggest that a minimum threshold value of 433 mm of rainfall can be a triggering factor for the landslides in this Himalayan terrane. Considering similar climatic and geologic factors, this threshold value may be extrapolated for other areas in the Arunachal Sub-Himalayan region. An attempt is also made to analyze the stability of slope (dry/saturated condition) through 2D numerical modeling. The results of the finite element method (FEM) are validated with the limit equilibrium method (LEM). Both critical strength reduction factor (SRF) and factor of safety (FoS) are significantly reduced due to saturation of the debris material. Pre-event simulation for dry and saturated conditions gives the critical SRF values of 1.12 and 0.72 in FEM and FoS of 1.009 and 0.786 in LEM, respectively. A conservative estimate shows at least ~ 15,352 m3 of sediments were generated from a single debris slide event. Predictably, a combined sediment volume from all the events contributes significant sediment load into the adjacent south-flowing Dikrong river. Heavy sediment flux leads to a cascading downstream impact with devastating floods, erosion, and aggradation besides frequent channel changes. This study is expected to contribute towards a better understanding of the disaster potential, cause and effect relationship in a highly landslide-prone terrane of the eastern Himalayas besides enhancing our understanding of upper catchment sediment generation and their trajectory in the Himalayan rivers. This also calls for the further analysis of space–time variability of the ISM to enable developing a landslide early warning system in Arunachal Himalaya. [ABSTRACT FROM AUTHOR]

A fully mechanised mining method using continuous miner (CM) for pillar extraction in single-pass is introduced in the year 2010 at Pinoura Mine of South Eastern Coalfields Limited, Bilaspur in India. Overall mining cycle time is reduced by single-pass pillar extraction as it does not require drivage of split galleries in pillars and support installation for such galleries. Further, inherent technical abilities of the deployed CM for faster cutting and quad-bolter for supporting, helped in faster recovery of pillars without creating any strata control issues. Rate of face advance varied between 5–15m/day with an average of 8m/day. Field observations found that CM based single-pass extraction is capable in dealing with the strata control issues during depillaring under weak and laminated (incompetent in nature) roof layers having rock mass rating value around 42. A total of eleven panels, have been depillared under the weak and laminated geology, ranging depth of cover from 59 to 149m in different panels of the mine. During field investigations in these panels, a maximum of 2.89MPa induced vertical stress is recorded and influence of caved roof over underground mining structures is observed up to 15m in the out-bye from the goaf edge. This paper deals with estimation of snook size and limiting roof movement value based on numerical simulation and field studies during the single-pass extraction below the incompetent geological formations. [ABSTRACT FROM AUTHOR]

The article discusses best practices concerning the use of rock bolting for underground coal mining. It compares the number of bolts used in coal and non-coal mines in the U.S. and India. It mentions a guideline issued by India's Directorate General of Mine Safety on rock bolting which includes classifying the roof rock of Indian coal mines based on rock mass rating. Charts are also presented that show general pattern and dimension of roof bolting system.

This article presents the challenges encountered during the stability analysis and stabilization of two Himalayan rock slopes supporting the Chenab Railway Bridge in India, which will be the highest railway bridge in the world after completion. Owing to the importance of the project, extensive geological investigations, in situ and laboratory tests were carried out using conventional and advanced methods to evaluate various intact rock, rock joints, rock mass properties and rock mass quality present at the site. Once the conclusive results were made regarding these properties, stability of slopes were evaluated against both structurally controlled and stress-controlled failures using the developed probabilistic approach due to the presence of high variability in intact rock, rock mass and rock joints properties. It was observed that while the slopes were stable against stress-controlled failures, the possibility of structurally controlled failures exists as observed in the probabilistic approach in which the conventional deterministic approach was not able to detect. Different stabilization measures, i.e. rock bolts, slope flattening, grouting, drainage and shotcreting, were designed at the site to reduce the probability of failures for the slopes, deformability of rocks present due to cavities and high aperture joints, shallow block failures along the slope surface and pore-pressure build-up. To check the efficiency of the stabilization measures, cross-hole seismic tomography is carried out at the site and further in situ measured displacements are compared with the displacements estimated using the developed probabilistic approach. The case study used in this paper is a real-time ongoing bridge project of global interest and the data and analysis presented will be of great benefit to the researchers and practitioners working on similar problems. [ABSTRACT FROM AUTHOR]

The Saptashrungi gad temple (SGT) situated on basaltic hills belongs to Deccan volcanic of Upper Cretaceous to Lower Eocene, is one among the 51 Shakti Peeths and most holy place for pilgrims. Rockfall is a major problem in the past and causing danger to the lives of the villagers settled at the toe of the SGT hill as well as the pilgrims who perform parikrama along the tracks. On the evening of 16 April 2011, an old woman died due to rockfall at SGT hill when she was performing parikrama, moreover, two persons got injured during the deliverance process of this old woman from the continuous rockfall activity. The problem of rockfall could be linked to rainfall, jointing, weathering, man-made or the compounding of all. In this research, the rockfall hazard analysis at SGT hill is assessed using both 2D and 3D rockfall programs along the two parikrama paths: Parikrama Path 1 (or the Badi Parikrama Path 'BPP'), and Parikrama Path 2 (or the Chhoti Parikrama Path 'CPP'). Also, the study area of the SGT hill has been divided into eight zones (Zone#01 to Zone#08), based on field observations, orientations of joint sets and hill slope faces and eighteen topographic profiles (AA' to RR') have been taken from these eight zones for rockfall analysis. A detailed topographic survey along with field investigation has been carried out along the temple for ascertaining the nature of rock, discontinuity orientations, and slope geometry. DEM has been generated using topographic profile in ArcGIS to facilitate the 3D rockfall analysis. Maximum rock block sizes are taken into the analysis and run-out distance, bounce height, kinetic energy and velocity of the basaltic blocks are evaluated separately. Based on the analyzed data, the rockfall hazard zone map has been prepared and site having potential rockfall risks have been identified. Finally, wire/net meshing has been proposed after removal of unstable blocks as a stabilization and protection measures. It is worth mentioning here that for the first time rockfall hazard assessment was made in such detail for a site. Suggestions made are implemented by the State Government for the protection of the temple as well as the life of pilgrims performing the parikrama from the rockfall. [ABSTRACT FROM AUTHOR]

Indian Strategic Petroleum Reserves Limited has awarded the packages of constructing underground unlined rock caverns for storage of 1.33 and 1.25 MMT of high sulphur crude oil at Visakhapatnam (Andhra Pradesh) and Padur (Karnataka) respectively to Hindustan Construction Company Limited, where-in Geoconsult is engaged for detailed design and site services. The unlined rock caverns for oil and gas storage call for site characterization in terms of geology, hydro-geology, geochemistry, geomechanics and geotechnics, which in turn facilitates assimilation, assessment and amalgamation of all relevant data to establish an overall geological and/or geotechnical framework for the projects. In general, the construction of an underground unlined rock cavern compriseds five principal activities: (i) geological and/or geotechnical site investigations; (ii) stability assessment; (iii) temporary rock supports design; (iv) excavation and related works; and (v) permanent rock supports re-design according to the observational approach. This paper outlines (a) the construction stage geological and/or geotechnical investigations to acquire geological/geotechnical data for rock mass quality appraisal as per Q-system and permanent rock support recommendations, (b) design criterion to utilize the rock itself as the principal structural material, to create as little disturbance as possible during the construction stage, and to add only the required supports, and (c) geotechnical instrumentation and monitoring to measure displacements at the surface and within the rock mass in order to fine-tune the excavation methods and rock supports, undertaken during construction stage of the project. Die Sondergesellschaft Indian Strategic Petroleum Reserves Limited beauftragte Hindustan Construction Company Limited mit dem Bau zweier nicht ausgekleideter Felskavernen zur Lagerung von 1,33 bzw. 1,25 Mill. t sauren Rohöls in Visakhapatnam (Andhra Pradesh) und Padur (Karnataka). Geoconsult ist mit der Ausführungsplanung und baubegleitenden Dienstleistungen betraut. Für die Herstellung der Kavernen zur Rohöl- und Gasspeicherung wurden die geologischen, hydrogeologischen, geochemischen, geomechanischen und geotechnischen Eigenschaften erhoben, was eine Erfassung, Zusammenführung und Verschmelzung aller relevanten Daten für den geotechnischen Rahmenplan ermöglichte. Generell umfasst die Ausführung fünf Hauptaktivitäten: (i) geologische und geotechnische Erkundungen; (ii) Stabilitätsberechnungen; (iii) Planung der temporären Stützmaßnahmen; (iv) Ausbruch und begleitende Arbeiten und (v) laufende Anpassung der permanenten Stützmaßnahmen an die Ergebnisse des geotechnischen Messprogramms. Dieser Artikel stellt (a) die geologischen Erkundungen während der Bauphase zum Zwecke der Erlangung geologischer und geotechnischer Daten zur Bestimmung der Felsqualität, des Q-Wertes und der permanenten Stützmaßnahmen, (b) die Planungsparameter für die Verwendung des Fels als primären Baumaterials unter möglichst geringer Auflockerung während des Ausbruchs und Einbau der benötigten Stützmittel, sowie (c) die geotechnische Instrumentierung und Monitoring zur Messung von Verschiebungen an der Oberfläche und im Gebirge zur Feinabstimmung der Ausbruchsmethode und der Stützmaßnahmen in der Bauphase, dar. [ABSTRACT FROM AUTHOR]