Some key aspects of logistics and application equipment for wet shotcrete Australian Shotcrete Society Coal Workshop 5 th September 2018 - Moranbah John Gelson - AuSS
Introduction The presentation will focus solely on the wet shotcrete process and key aspects of the transport & robotic application required. The generic aspects should apply to all mines. However we need to always be mindful of the total shotcrete process. This holistic approach must be applied for a successful shotcrete operation.
The Holistic approach for the shotcrete process Future environment and load conditions logistics Site control - Monitoring and action Modern, relevant Specifications Inc. Fibres Ground and H 2 O conditions acting on structure Durable sprayed concrete structure Capable and trained applicators QA/QC Testing Regime Correct mix design and chemical choice Hand or robotic application. Special modifications for coal mines Wet-mix or dry-mix method?
Some Mining Parameters to consider - The mine development plan The shotcrete ground support plan Total number of headings, cycle operations Batch plant size, type wet or dry Drift or Shaft. (Grade, length & depth) Roadway dimensions and minimum radii Concrete truck / kibble size and numbers Tramming distances in the mine Suitable shotcrete sprayer numbers Equipment support technical, service, refurbishment, spares Costs overall taken over time, to include not just capital but running costs over life of machine and roadway OH&S issues Mine regulations applicable Innovation and future developments
Vertical Transportation : Boreholes / Slicklines Shaft Mines Tunnel Project Kettle pressure reducer
Drifts / Declines / Horizontal transport: Transmixers / Agitators - Hard Rock
Agitators and Transmixers Hard Rock Capacity matched to heading size/multiple headings (5m3, 7m3) Drum design For limited height For batching or remixing shotcrete (Agitator type) Brakes mine design vehicle Local mining guides / codes Axles matched to full payload Articulation for tight turns Discharge to sprayer Heavy Duty
Application: the Business End of the Process Shotcrete : Mix Design Design/Chemicals/Manufacture Surface Transport Vertical Logistics: Borehole, Slickline or Decline Underground reception Transportation: Agitators, Transmixers, Eimco +Hopper Sprayer + Operator Equipment selection Pump filling rate Low pulsation Integrated accelerator dosing Lighting Maneuverability, reach Operator training Consistency / Reliability In-situ Sprayed Shotcrete
Sprayers many makes and types but application dictates
Sprayers many makes and types but application dictates
Sprayers Mining / Tunnelling key features Robustness heavy duty carrier Working height & manoeuvrability Diesel or Electric or Battery? Spraying capacity On board compressor? Modern minimal pulsation pump Tramming capability Ease of operation and spare parts Non-corrosive accelerator tank Pump hopper matched to transmixer / kibble Integrated accelerator dosing system Boom stability Pressure cleaner / oiler High pressure scaling Lighting!
Some operational spraying considerations Safety assessment of ground Correct sprayer positioning Nozzle distance and orientation Substrate preparation Correct air pressure Correct lighting Secure operator vantage point (from supported ground) Cable or radio remote, (cable in coal) Maneuverability Experience and operator capability Ease of operation Simple cleaning Controlled use of accelerator Take your time 12-15m3 /hr max.
Wet Shotcrete in Coal Brief History Stratacrete first started applying wet shotctrete u/g in coal in 1998. Some of the mines that used wet shotcrete from 1998 to 2009 are Southern Colliery Newlands Moranbah North Kenmore Beltana Goonyella 13
14 Wet Shotcrete coal rigs - Stratacrete
Coal Applications - Mains and Gate roads C&C Civil & Mining Rig 15
Coal Mine Requirements Explosive Risk Zones for Diesel Engines ERZ0 is the area of a mine in which there is an unacceptably high probability that there will be a presence of methane in a concentration greater than 2% and it is considered that there is an unacceptable level of risk for an internal combustion engine to operate in an area with this classification. ERZ1 is an area of a mine in which on almost all occasions the methane level will vary between 2% and 0.5% but there is the possibility on some occasions the concentration will exceed 2% creating an unacceptable level of risk of an explosion on the occasions such an event occurs; refer section 288 of CMSHR2001 for full definition of ERZ1 zone. Diesel engines used in these zones needs to be explosion protected. NERZ is an area of the mine where it is considered there is negligible risk of an explosive mixture of explosive gas being present. This standard addresses the testing and assessment of engines to ensure that they are explosion protected and can operate safety in areas of the mine classified as ERZ1. Additionally - AS/NZS 3584:2; 2003/8 - Diesel engine systems for underground coal mines; Explosion protected AS 2380.6 1988 Electrical equipment for explosive atmospheres Increased safety AS 2380.7 1988 Electrical equipment for explosive atmospheres Intrinsic safety AS/NZ 4242-1994 Mining equipment- Electrical wiring systems at extra low voltage 16
Optimized shotcrete application - the importance of high slump and low pulsation modern pumps Standard pump Shotcrete flow Accelerator flow Optimised pump Low pulsation concrete pumping Continuous flow accelerator pumping Good workability of shotcrete / concrete High slump shotcrete To give best piston fill 17
High Pulsation - results in layering causing weaknesses Layering, neat accelerator
Accelerator Dosing System
Accurate monitoring of accelerator & shotcrete
Accelerator dosage Thermal Imaging Thermal imaging can be used to examine the flow of shotcrete and accelerator during spraying. From the thermal videos, particularly with the pumps that provide more interruption in concrete flow, the darker blue/purple from the nozzle is pure accelerator. This hits the concrete surface and makes it go bright yellow immediately causing a surge in the heat of hydration due to accelerator overdosing of the concrete surface. This would cause a hardened substrate surface for the overlying shotcrete. Net result is poor bonding and layering of the shotcrete. Low pulsation pump "Standard" sprayed concrete pump
Recap : Requirements for high quality modern homogenous sprayed concrete 1. Suitable concrete mix design with suitable concrete additives 2. Suitable alkali-free accelerator at correct dose rate 3. Low pulsation and stable flow of concrete from pump to the nozzle 4. Constant flow of accelerator integrated with shotcrete pump output 5. Proper mixing of accelerator into concrete flow at the nozzle 6. Suitable volume of air from compressor or from external air supply 7. Experienced operator 8. Good QA/QC 22
Remote Shotcrete sprayer monitoring Accelerator dosing & usage Concrete temperature Ambient temperature Accelerator temperature Shotcrete pump speed Shotcrete pump hydraulic pressure Shotcrete (m3) used last shift Accelerator (L) used last shift
The Future of Mining Equipment? Battery Electric Caterpillar Sandvik General Electric
The Future of Mining Equipment? Electric Battery
Battery U/G Mining Equipment - Benefits All the main suppliers of u/g mining equipment are either testing battery equipment or developing them. These include Atlas Copco, Sandvik, Normet, Maclean, Epiroc, General Electric, Caterpillar, ETF and many more. The hard rock mines lead the way but coal and tunnelling markets will follow. Benefits are enormous 80% less heat generated compared to diesel engines 80% less energy used compared to a diesel engine No hydrogen gas production like old lead acid batteries. Hence charging stations simplified. Zero emissions, hence no diesel particulates, NOX, CO, etc (OH&S) Ventilation costs massively reduced Maintenance costs greatly reduced Noise reduced greatly and assists in better communications Automation much simpler, and tele remote operation from anywhere via suitable internet. Opportunity to eliminate downtime due to blasting. 26
Thickness control Consistent remote control Increased automation New fibre types Tier 4 Diesel Engines Electric/Battery power Alternative raw materials Greater geotechnical understanding of how shotcrete works so well Shotcrete for the Future
The underground space becomes connected Visualization & Data analysis Data Mule Data logging Sprayed concrete UG Wireless Access point Data logging Laser scanning
Fleet monitoring showing key KPIs and alarms Spraymec MF050D 100 30m3 9000m3 Engine 615h Powerpack 540h 75h 85h Spraymec MF050D 105 35m3 9110m3 Engine 820h Powerpack 540h 150h Utimec LF100D 202 205t 3020t Engine 2920h 20h
Example data from a real customer in Finland: Accelerator usage vs. concrete pump output Concrete pump ouput (black) Accelerator setting (blue)
Data will be available on multiple devices, anywhere Telemetry Reports Email SMS Alarms Process
Thanks for your attention