Mining with Paste Fill

Transcription

1 Mining with Paste Fill Mehmet Yumlu, Principal Mining Engineer AMC Consultants Pty Ltd AusIMM Cobar Mining Seminar AMC Con nsultants Pty Ltd

2 Outline Introduction ti What is Paste Fill? Why Using Paste Fill? Paste Fill System Design Paste Fill Making Process Distribution and placement Mining with Paste Fill - Case Studies nsultants Pty Ltd AMC Con 2

3 What is paste fill? AMC Con nsultants Pty Ltd Paste fill is dense non draining slurry made from single or a combination of several suitable solid materials produced to toothpaste consistency For surface disposal no cement required For underground backfill cement always required Terminology Paste (P) Paste fill (PF) Paste backfill (PB) Cemented paste backfill (CPB) Composite fill (CF) Paste aggregate fill (rocky paste fill) (PAF) 3

4 Why Paste fill? AMC Con nsultants Pty Ltd engineered product consistent t high h quality suitable for most mining methods - versatile lower cost for a given exposure duty - economic reduces surface footprint - environment friendly allows extraction of ore pillars - increasing resource extraction allows effective local and regional ground support - safety fast filling rates enables shorter stope cycle times - productivity non segregating g g - reduced dilution 4

5 What are Paste Fill Duties in UG Mining? When integrated t into the mining i cycle paste backfill serves as a working platform, as a wall to work alongside as an engineered artificial back As a local and regional ground support paste fill provides confinement to ore pillars and the host rock, and prevents unravelling, thereby limiting convergence and subsidence into the mine voids. nsultants Pty Ltd AMC Con 5

6 Some Myths. Paste is NOT The solution to all future mine fill problems A method which will enable a mine to place all tailings underground A fill type by which all the water is absorbed through cement hydration nsultants Pty Ltd AMC Con 6

7 Paste Fill Design Paste fill is engineered to meet the following criteria Flow properties (rheology) delivery of paste from surface to underground via boreholes and pp pipes at the highest practical pulp density Strength properties paste to remain stable when exposed to static or dynamic loading conditions experienced by the mining operation» This includes short term during the local mining operation and» Long term stability against regional seismicity nsultants Pty Ltd AMC Con 7

8 Strength Design A l ti l Analytical Empirical Numerical 8 AMC Consultants Pty Ltd

9 Rheology Design Rheology is the study of the flow properties of fluids Water is a Newtonian fluid If you tip water out of a glass it will start to flow immediately Pastefill is a non-newtonian fluid If you want to get toothpaste out of the tube, you must squeeze it first Yield stress is the measure of how much work is required for the paste to start flowing nsultants Pty Ltd AMC Con 9

10 Typical Paste Fill Characteristics AMC Con nsultants Pty Ltd Particle size distributiontion Minimum 15% passing 20 micron No top size Rheological properties Yield stress for surface disposal less than 100 Pa Yield stress for backfill 100 to 700 Pa Strength properties Stiffness, E=150 to 450 MPa Can be engineered to desired strength ( 100 kpa to 5 MPa) Typical strength values (UCS) 300 to 1,000 kpa for vertical exposures >1,000 kpa for undercut exposures 10

11 What are methods of making paste fill? 11 AMC Consultants Pty Ltd

12 What are the delivery options? Gravity delivery to borehole Surface conveyor to borehole Pump delivery thru Borehole Decline Agi truck delivery to borehole Internal boreholes Level pipelines nsultants Pty Ltd AMC Con 12

13 Paste fill barricades Engendered shotcrete barricades required to retain paste fill Planar Arched Mullock waste pile Combination of waste and shotcrete Cemented rockfill nsultants Pty Ltd AMC Con 13

14 Paste Fill Operations Increasing Popularity nsultants Pty Ltd AMC Con About 100 operations worldwide Many ongoing projects Canada = 35 / 2 Australia = 24 / 5 South America = 12 /4 Europe = 11 /8 Asia = 7 / 9 Africa = 5 /1 14

15 Case Study 1 Underground Cu and Zn operation Production 1.0 MTPA Mining methods Longitudinal & transverse sublevel stoping Drift and fill nsultants Pty Ltd AMC Con 15

16 Case Study 1 Online paste fill plant, 45 m 3 /hour Using full tailings, SG of 4.5 PSD (50-60% passing 20 microns with P80 of 63 microns) Solid density 82%w/w (49.5%v/v) Slump: 7 10inch Paste bulk and dry density: 2.6 and 2.0 tonnes/m 3 Stope size 20m H x 7m W x 30m L (panels) Target design strength: 1.0 MPa AMC Con nsultants Pty Ltd GP cement; 7% (150 kg/m3) for primaries and 5% (110kg/m3) for secondaries Pump delivery, 125 mm diameter thru decline and boreholes Shotcrete barricades 16

17 Case Study 1 17 AMC Consultants Pty Ltd

18 Case Study 1 18 AMC Consultants Pty Ltd

19 Case Study 2 Underground d gold mine Production 450 TPA Mining method Underhand cut and fill Backfill types Paste fill Rockfill nsultants Pty Ltd AMC Con 19

20 Case Study 2 Dry paste fill system, stem 120 m 3 /hour Using volcanic tuff PSD (30% -20 micron, P micron), SG of 2.55 Solids density 50%w/w (28%v/v) Wet and ddry bulk lkdensity t/m3 and d t/m3 GP cement; 15 to 20%w/w (100 to 150 kg/m3) Target design UCS >1,500 kpa Stope size 5m W x 5m H x 30m L (cells) AMC Con nsultants Pty Ltd Shotcrete barricade Gravity delivery thru borehole, 150mm dia distribution system 20

21 Case Study 2 21 AMC Consultants Pty Ltd

22 Case Study 2 Previous cut Lift 1 Next cut Lift 2 22 AMC Consultants Pty Ltd

23 Case Study 3 Underground d Zn and Pb mine Production 1.6 MTPA Tabular flat dipping massive sulphide orebody (dip <20 ) Mining methods Drift and Fill Bench stoping Backfill Rockfill AMC Con nsultants Pty Ltd Paste fill 23

24 Case Study 3 Online paste plant using DCT, 100 m 3 /hour Full mill tailings (35% passing 20 micron, P micron), SG of 3.6 Solids density 75%w/w (48%v/v) Wet and dry bulk density 2.15 t/m3 and 1.6 t/m3 Yield stress 50 to 100 Pa (10 to 10.5 inch slump) Pump delivery through decline, 200 mm diameter, 3.5 km long Shotcrete barricades Stope size 10m W x 6m H x 150m L AMC Con nsultants Pty Ltd Target design UCS 500 cement (100 kg/m3) Slag 60% : cement 40% 24

25 Case Study 3 25 AMC Consultants Pty Ltd

26 Thank you for listening A ti? Any questions? 26 AMC Consultants Pty Ltd