JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD

Pre-Requisites

NIL

Course Objectives:

• To study and understand various aspects of rock mechanics and its application to mining.
• Introducing the various instrumentation and measurement methods.
• To study the theories of failure and approaches used for open pit and underground designs.
• To understand various aspects of supports and their design for various situations.
• To know the various statutory aspects like CMR, MMR and the relevant DGMS circulars related to this course. Course outcome: The students will have knowledge on rock mechanics instrumentation, approach to pit slope stability, theories of subsidence and failure of rocks. They will also know about design of underground openings and methods of stowing.

UNIT - I

Physical and Mechanical Properties of Rocks: Definition of some important terms used in rock mechanics, application of rock mechanics in mining, Physical properties of rocks-density, porosity, moisture content, permeability, water absorption various indices of rocks like hardness, Protodynakov index, slake durability index, impact strength index, etc, Preparation of test specimens, laboratory determination of mechanical properties of rocks-compressive strength, tensile strength, flexural strength, shear and triaxial strength, modulus of elasticity, Poisson’s ratio. Dynamic wave velocities, dynamic elastic constants, their determination in the laboratory, application in mining, time dependent properties of rocks, creep, mechanism of creep of rocks-different stages, rheological models.

UNIT - II

Supports and Supporting: Various methods of roof examination, objectives and limitations of supports, ground forces and in situ stresses, pressure arch theory, evolution of supports, conventional supports- timber and steel supports, arches, yielding supports; rock and cable bolting, shotcreting, roof stitching, support of shaft bottoms, galleries, junctions and places of roof falls, freshly exposed roof supports, longwall powered supports. Design of systematic support rules for B & P and longwall (face and roadways) - development, depillaring, etc.

UNIT - III

Rock Mechanics Instrumentation, Pit Slope Stability: Convergence indicators, load cells, strain gauges, flat jacks, LVDT, dial gauges, pressure cells and recorder, anchorage testing equipment, laboratory and in situ measurements, hydraulic fracturing rock mechanics, strata instrumentation for B & P and longwall workings, Approach to slope stability, slope parameters, different types of slope failures, factors affecting slope stability, introduction to methods of failure, analysis, determination of factor of safety,. Introduction to different rock slope stabilisation techniques,

UNIT - IV

Subsidence and Stowing: Theories of subsidence, factors affecting subsidence, subsidence surveys, subsidence prediction techniques, subsidence control – surface and underground measures, pseudo- mining damage. Selection and preparation of stowing materials, principal methods of stowing, collection, fields of application and limitations, surface, underground and face arrangements, design of stowing plants.

R18 B.TECH MINING ENGG. III YEAR

UNIT - V

Theories of Failure, Pillar Design, Design of Underground Workings and Rock Burst: Different theories of failure of rocks, modes of failure - Griffith, Coulumb-Navier, Mohr, Hoek-Brown, empirical criteria, etc. and their field of applications, Strength of pillars, barrier and shaft pillar design – roof load estimation, factor of safety, various formulae, rock burst and bumps - phenomena, causes, prediction, monitoring and control, gas outbursts, stress distribution in underground workings including bord and pillar and longwall workings.

TEXT BOOKS:

• 1. Obert, L. and Duvall, W.I., Rock Mechanics and Design of Structure in Rock John Wiley and Sons Inc., New York, 1967.
• 2. Vutukuri, V.S. and Lama, R.D., Handbook on Mechanical Properties of Rocks, Vol.I, II, III and IV, Transtech Publication Berlin, 1974/78.
• 3. Peng S.S., and Chiang, H.S., Longwall Mining, John Willey and Sons, New York, 1992.

REFERENCES:

• 1. Brady, B.H.G. and Brown, S.T., Rock Mechanics, Wiley Interscience, 1985.
• 2. Hoek, E and Brown, E.T., Underground Excavations in Rocks, Institute of Mining Metallurgy, London, 1980.
• 3. Jumkis, A.R. Rock Mechanics, Transtech Publications, Berlin, 1983.
• 4. Internet: www.miningindia.com R18 B.TECH MINING ENGG. III YEAR MN604PC: GROUND CONTROL & INSTRUMENTATION LAB AND COMPUTER APPLICATIONS