Innovative Blast Free Mining Methods for Aggregate Quarries " Ramesh Bhatawdekar, Edy Tonnizam Mohamad, Firdaus Azlan Department of Geoteknik and Tran

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1 Innovative Blast Free Mining Methods for Aggregate Quarries " Ramesh Bhatawdekar, Edy Tonnizam Mohamad, Firdaus Azlan Department of Geoteknik and Transportation, Faculty of Civil Engineering, University Teknology Malaysia, G.K.Pradhan Department of Mining Engineering AKS University, Satna, India

2 Introduction Concrete Per capita consumption 1 T Consumption of natural aggregates concrete Aggregates are commonly mined with blasting worldwide Blasting increases various hazards Study of geological factors necessary for optimizing blast design as well as for breaking rock with new technology Physio mechanical properties affect selection of technology New Innovative Technologies under development for breaking rock with minimum hazards

3 Environmental Hazards due to Blasting Type of hazard Possible Impact Common Causes Fly-rock Property damage, Geological conditions, Serious injury, Loss of life Over charge of explosives, Stemming length, back break Ground Vibration Annoyance to public, Exceeding max charge/ delay Cracks in property Air Blast Annoyance to public, Use of detonating fuse Glass pane breakage Fumes, dust Local hazard TECHNOLOGICAL DEVELOPMENT IN INITIATION SYSTEM Ordinary detonators Electric delay detonators- Sequential Blasting Machine- Cord relays -Non electric detonators- Electronic detonators

4 YEAR 450 BC s Technological Milestones in Mechanical Cutting TECHNOLOGICAL EVENT Surface scratching by Paleolithic miners for stone implements Development of bucket wheel excavator Concept of continuous and mass mining systems Surface miners emerge as a clean mining system Hofmann, reported use of continuous surface miners as a technology for opencast. Gujrat Ambuja Cement developed Wirgen 1900 Surface Miner for trial basis Introduction of high wall system Surface miner introduced in Indian Coal Mines

5 Types of Natural Aggregates India Basalt Calcgranulite Charcnockite Chert Granite Greywacke Limestone Magnetite Muscovite Quartzite/ Quartz wacke / Greywacke Quartz/Quartz Mica Schist Sandstone Trap Rock Malaysia Agglomeratic tuff Chert Glassy Acidic to Intermediate Volcanic Granite Geyseites Hornfels Impact rocks Intermediate Volcanics Metaquartzite Mylonized rocks Quartzite Rhyolite Sandstone Siliceous Shale

6 Selection of Rock Excavation Process, Machines

7 Evaluation of Rock Breaking Methods for Rock Breaking Systems Determining rock strength compressive and tensile strength Determining energy related indices- crushing energy factor Measurement of rock breaking parameters cutting resistance, depth

8 Rock Properties

9 Prediction of specific energy required for cutting (Barendsen, 1970) Barendsen, (1970)

10 Determination of excavation possibilities (Atkinson, 1971)

11 Pettifer Fookes chart Discontinuity Spacing Index Vs Point Load Index

12 Overall Assessment of Excavability of Rock Mass

13 Excavalibilty of Jointed Rock Mass using Geological Strength Index (GSI)..

14 Summary Excavability of Jointed Rock Mass using GSI The Geological Strength Index (GSI) used to assess the ease of excavation of rock masses :Figure A ( Is 50 \3 Mpa ) and Figure B (Is 50 C 3 Mpa) Blasting required GSI values are greater than 65 when Is 50 C 3 MPa and 60 when Is 50 \ 3 MPa, hence blasting is usually required in massive, blocky and very blocky rock masses or when joints are tight. Successful ripping is generally achieved for rock masses with GSI values between 20 and 45 In the transitional zone between the ripping and blasting areas of the GSI charts, excavation with hydraulic breakers is necessary. The proposed classification is applicable only for rock masses where discontinuities control the excavation, thus is should not be used for the assessment of excavation in heterogeneous rock masses

15 Surface Miner.

16 Selection of Surface Miners Geotechnical parameters Uniaxial Compressive Strength (UCS) Tensile Strength Moisture Content Abrasivity Brittleness Stickiness Percentage of silica Rock properties Schmidt hammer for Rebound Test Scan line survey to determine the discontinuity by carrying out this test at the cutting edge/face created by the surface miner, Laboratory investigations Point Load Strength Index (PLSI in MPa) using BEMEK tester.

17 Parameters Influencing Cuttability of Surface Miner

18 UCS of Rock Vs Surface Miner

joint set number of Q system, relative ground structure number, joint

19 Rippability based on Excavability Index The excavatability index depends upon mass strength number, rock quality designation (RQD), joint set number of Q system, relative ground structure number, joint roughness number of Q system, and joint alteration number of Q system (Kisten, 1982).

Hydraulic Rock Breaker Various Manufacturers are

secondary blasting Output 180 to 200 TPH Operating

20 Hydraulic Rock Breaker Various Manufacturers are available for supplying Hydraulic Rock Breakers mounting on Back Hoe Excavators. Suitable application for breaking boulders to avoid secondary blasting Output 180 to 200 TPH Operating pressure 300 PSI Still need development to utilize Hydraulic Rock Breaker as Primary Breaking

21 Controlled Foam Injection Technology The method uses high-pressure foam to initiate, pressurize and propagate controlled fracturing in rock. The foam is injected to the bottom of a relatively shallow pre-drilled hole in the rock to be broken by means of a barrel incorporating a hole bottom sealing met. The pressures required to fracture and excavate rock are significantly less than required in methods based upon the use of small explosive. Air blast and fly rock are reduced and thus allowing application in urban and environment sensitive area. Controlled Foam Injection (CFI) method uses as high as 83 MPa (12,000 psi) pressure when breaking a hard granite. Breakage efficiencies of 0.06 m 3 tof0.24 m 3 per break observed during trials.

22 Rock Breaking using Chemical Methods Expansive Mortar which can fracture rock or concrete with expansive force of 15,000 psi (1034 kg/cm 2 ). Productivity of mechanical breakers is also increased by fracturing rock. Product can be used for pre-splitting rock in sensitive conditions. Expansive Mortar can be used in dry and watery conditions hole diameter upto 76 mm. Application : For boulders, depth of hole is 65 to 70% height of boulder. 10 times hole diameter is distance between holes and holes are drilled in square or diamond pattern. Presplitting Mortar is added to holes and after 6 hours, boulder or surface is cracked.

$Accelerates removal time once fracturing occurs Works underwater in difficult conditions Minimizes risk in high exposure situations No license for storage of rock splitting$

23 Rock Splitting Mortar Advantages Eliminates noise, fly rock and vibration potential caused by blasting or heavy mechanical means Increases productivity of hydraulic rock breaker Accelerates removal time once fracturing occurs Works underwater in difficult conditions Minimizes risk in high exposure situations No license for storage of rock splitting mortar

24 Plasma Technology for rock breaking A group of scientists at the Korea Instiute of Geology, Mining and Materials (Min et al.,1997) established the plasma blasting method for rock fragmentation.

25 Plasma Technology Process

26 Conclusion Blasting has fly-rock, ground vibration, air-blast and fumes as hazards. In environmentally sensitive areas, various technologies are being tried for more than 2 decades Aggregates.produced from granites, basalts, quartzite, chert, limestone, etc Study of compressive strength, tensile strength, geological strength Index for excavation are necessary to decide type of excavation method Surface Miners, Hydraulic Rock Breaker, Rippers are suitable for certain rock types with geological features (very blocky to disintegrated), for blast free mining Hydraulic Rock Breaker is used mainly for boulder breaking. Further development required for primary breaking. Rock splitting Mortar with Hydraulic Rock Breaker can give advantage of rapid breaking of rock. Rock Splitting Mortar,Foam Injection technology and Plasma Technology are immerging technologies which need to be established for aggregate quarry application

27 Points for discussion Status of Blast Free Mining at China Whether proven technologies like Surface Miner or Hydraulic Rock Breaker are in use at China? Any other blast free technologies being used in China. Future scope of blast free technologies in China.

28 ..

29 References [1]. Atkinson, T.: Selection of Open Pit Excavating and Loading Equipment. Transaction Institute of Mining and Metallurgy Section A, A101 A129 (1971) [2] Barendsen, P.: Tunneling with Machines Working on the Undercutting Principle. In: Goodman, J.A. (ed.) The Technology and Potential of Tunneling, Proceedings of South African Tunneling Conference, pp (July 1970) [3 ] Janus Res, K. Wladzietczyk, Ajoy K Ghose Book- Environment Friendly Techniques of Rock Breaking [4] Min, J. S., Chung, Y. W., Lee, H. J., & Lee, D. N. (1997). A study on the environmental and safety problems and their remediation around mining areas. Korea Institute of Geology, Mining and Materials (Vol. 32). Research Report KR-97 (C). [5] Pettifer GS, Fookes PG (1994) A revision of the graphical method for assessing the excavability of rock. Q J Eng Geol 27: [6] Pradhan, G. K., Prakash, O., & Thote, N. R. (2014). Blast Free Mining in Indian Surface Coal Mines Current Trend. In Mine Planning and Equipment Selection(pp ). Springer International Publishing [7] Swamy R. N. (1992) Book- Alkali Silica Reaction, [8] Tsiambaos, G., & Saroglou, H. (2010). Excavatability assessment of rock masses using the Geological Strength Index (GSI). Bulletin of engineering geology and the environment, 69(1), [8] Venkatesh, H. S., Bhatawdekar, R. M., Adhikari, G. R., & Theresraj, A. I. (1999). Assessment and Mitigation of Ground Vibrations and Fly rock at a Limestone Quarry. In Proceedings of the Annual Conference on Explosives and Blasting Technique (Vol. 2, pp ). International Society of Explosives Engineers. [9] Young, C. (1999). Controlled-foam injection for hard rock excavation. In Rock Mechanics for Industry, Proceedings of 37th US Rock Mechanics Symposium, Vail, Colorado (Vol. 1, pp ). [10] YOUNG, C., & GRAHAM, C. (1999). CONTROLLED FOAM INJECTION PROGRESS TOWARDS AUTOMATED HARD ROCK EXCAVATION. In Proceedings of the 5th International Symposium on. Mine Mechanization and Automation, Sudbury, Ontario (p. 39). [11] [12] [13]

ENGINEERING GEOLOGY AND ROCK MECHANICS

ENGINEERING GEOLOGY AND ROCK MECHANICS SKAA 2712 ENGINEERING PROPERTIES OF ROCK MASSES PROF. MADYA DR. EDY TONNIZAM BIN MOHAMAD DEPT. OF GEOTECHNICS AND TRANSPORTATION FACULTY OF CIVIL ENGINEERING UTM