A DISCOURSE ON THE DEVELOPMENT OF AUTOMATIC UNDERGROUND TRACTORS AT MATLA COLLIERY

Transcription

1 25 June 2015 A DISCOURSE ON THE DEVELOPMENT OF AUTOMATIC UNDERGROUND TRACTORS AT MATLA COLLIERY Presented to SACEA Technical Symposium by: Hennie Lombard Manager Engineering Matla Colliery

2 CONTENTS 1 SECTION DESCRIPTION 1 Objective Of Presentation 2 Introduction: Mine Layout & Mining Methods 3 Background 4 Development History 5 PDS Development 6 Current Design 7 The Way Forward 8 Questions

3 1. OBJECTIVE OF THE PRESENTATION 2 To share Matla s learnings on their journey towards developing a userfriendly, legally-compliant, underground tractor. To this end, to share information on the development of a machine that would be: 100% compliant with proposed PDS/CAS legislation; Capable of full automatic operation in the underground environment. and to share the challenges encountered along the journey, and the solutions developed to address them.

4 2. INTRODUCTION: MATLA MINE LAYOUT AND MINING METHODS Kriel 10,950 Ha Leandra

5 2. INTRODUCTION: MATLA MINE LAYOUT AND MINING METHODS

6 3. BACKGROUND 5 In mid-2010, Matla Colliery embarked on a program to replace their fleet of underground tractors. Issues experienced with old fleet: OPERATIONAL issues typically experienced with ageing machines, such as: frequent breakdowns, leading to low availability; spares not available; increasing maintenance costs. LEGAL COMPLIANCE issues such as: machines not PDS-ready for impending new legislation; no ROPS/FOPS protection; high noise levels (open cab body) braking systems not compliant (not fail-safe ); on-board crane not legally compliant.

7 3. BACKGROUND 6 OPERATIONAL/SAFETY issues due to poor/outdated design, such as: stone dusting issues with manual tractors; machine runaways caused by coasting in neutral on declines; Old technology other safety-related incidents, for example: Burst scrubber pipe, resulting in burn wound; Clutch disintegrating, causing injury to operator.

8 3. BACKGROUND 7 In December 2010, capital for the replacement of 38 tractors was approved. In February 2011, specifications were compiled, and a RFQ (Request for Quotation) was issued on the open-market to 4 established suppliers. In March 2011, after adjudication, initial contract placed for 4 trial machines with 2 suppliers ( A and B ), in line with Exxaro s strategy to have 2 tractor suppliers for the Exxaro group. In Dec 2012, contract with Supplier B cancelled due to supplier unable to meet delivery to contract specifications, despite repeated extensions to contract. In February 2013, balance of machines subsequently awarded to Supplier A, with a Memorandum of Understanding to develop their machine to Exxaro specifications.

9 4. DEVELOPMENT HISTORY 8 Initial Machine Features: Tubing frame; Single door enclosed ROPS/FOPS cab; 3 seats Dimensions: frame length 5.2m width 2.3m height 2.0m ground clearance 300mm PTO: hydraulic (32-38KW); Hydraulic starters; Failsafe brakes: below chassis; Dashboard: odd gauges; Transmission & gear selector: standard 3-speed transmission with pneumatic gear selector; 6-core radiator with standard fan; Hytronic electrical system.

10 4. DEVELOPMENT HISTORY 9 Machine Frame Modifications: Machine length reduced to 4,25m: Allows entry into cage with fantail; Improved turning radius and manoeuvrability. Ground clearance increased to 400mm. Moved from tubing to profile cutting and fabrication for the chassis: makes fabrication easier and more accurate. Fail-Safe brakes moved from bottom of machine to rear: Reduce fouling, binding and ease of access for maintenance and visible inspection possible; Increased frame width from 2,3m to 2,5m and opened up cabin width by 200mm.

11 4. DEVELOPMENT HISTORY 10 Machine Cabin Modifications Right hand door added to design. Hinges and latches redesigned. Door rubbers moved from chassis to door. Improved ventilation: Front middle window swings open Rear side windows slide open Manually operated cabin fan incorporated

12 4. DEVELOPMENT HISTORY 11 Transmission and Starter Modifications: Gearbox changed from 3 to 4 forward speeds to include a crawler gear for stone dusting. Transmission overheating: automatic protection circuit incorporated to safeguard transmission from starting in high gear: overrides gear selector (4-3) Hydraulic-starter changed to air-starter to be in line with air starters used on LHD fleet.

13 4. DEVELOPMENT HISTORY 12 PTO Modifications: HYDRAULIC PTO (32-38Kw) originally fitted. Insufficient power to stone dust seams above 4m. Changed to MECHANICAL PTO (48-60Kw) incorporating: Independent PTO clutch. Drive shaft with reduction box (reduces strain on transmission). Mechanical PTO failures due to excessive torque: Reduction ratio increased (from 3:1 to 3,5:1) Slip clutch installed to protect against overload. Magnetic coupling installed. Unsuccessful was damaged. Reduction ratio increased again. Final change to PTO: Fluid coupling for soft engagement and overload protection. Overrun clutch installed to reduce PTO brake wear. Safety devices ensure PTO is engaged only when transmission in neutral and engine at idle RPM.

14 4. DEVELOPMENT HISTORY: MECHANICAL PTO LAYOUT 13 Reduction gearbox Shearing Pin Wet engagement clutch Over-Run clutch

15 4. DEVELOPMENT HISTORY: STONEDUST VIDEO 14

16 4. DEVELOPMENT HISTORY 15 Cooling System Modifications: ORIGINAL COOOLING SYSTEM/S CONFIGURATION: Engine cooling: water-cooled, standard 6-core radiator & fan arrangement. Hydraulic/transmission oil cooling: combined cooler. Engine and transmission failures due to overheating on long distance, high load, high speed conditions. Modifications made: Separate transmission cooler installed, using engine s water cooling circuit; original combined cooler modified to separate hydraulic oil and transmission oil coolers; Additional vents put into bonnet; Radiator core was increased from 6 to 8 rows. Overheating still occurred. Modifications made: Water circuit changed to force more water through transmission cooler; Fan replaced by specially designed fan to increase airflow and suction capability, and cowling modified.

17 4. DEVELOPMENT HISTORY 16 Cooling System Modifications (Continued): Overheating still occurred. Supplier discovered that fan drive pulley diameter from OEM were incorrect. Correct size pulley was fitted. Radiator core changed back to 6 rows. End of overheating problem.

18 4. DEVELOPMENT HISTORY 17 General Modifications: Front bonnet changed to increase visibility. Pneumatic circuit modified to include lock-up valve to store air pressure. Diesel tank capacity increased to 110 litres to give 8-9 hours operating time (under average conditions). Original 1 X external hydraulic circuit increased to 3. Scrubber tank shape and capacity modified to increase water pressure supply to scrubber at steep angles, to reduce trips. Dashboard improved to provide the following information: Engine oil pressure Engine oil temperature Transmission oil pressure Transmission oil temperature Pneumatic system pressure Pneumatic brake system pressure Hydraulic system oil pressure

19 4. DEVELOPMENT HISTORY 18 Crane Development And Modifications: Original (1 st ) crane equipped with telescopic boom: 750 5m; Outriggers with vertical and horizontal cylinders Difficulties encountered when lifting large objects. Crane modified to knuckle configuration: 1.4 ton 5m; Outriggers upgraded to spider-leg design; Chassis upgraded to reduce twist during crane use; Engine fan and cowling updated to accommodate some flex. All other modifications transferred as per the standard PTO tractor upgrades.

20 5. PDS DEVELOPMENT: REGULATIONS 19 Extract from Reg (Gazetted 27 Feb 2015) Collisions between trackless mobile machines and pedestrians Regulation The employer must take reasonably practicable measures to ensure that pedestrian are prevented from being injured as a result of collisions between trackless mobile machines and pedestrian. At any mine where there is a significant risk of such collisions, such measures must include at least the following: All electrically or battery powered trackless mobile machines All underground diesel powered trackless mobile machines must be provided with means: (a) to automatically detect the presence of any pedestrian within its vicinity. Upon detecting the presence of a pedestrian, the operator of the diesel powered trackless mobile machine and the pedestrian shall be warned of each other's presence by means of an effective warning; and (b) in the event where no action is taken to prevent potential collision, further means shall be provided to retard the diesel powered trackless mobile machine to a safe speed where after the brakes of the diesel powered trackless mobile machine are automatically applied. The prevent potential collision system on the diesel powered trackless mobile machine must fail to safe without human intervention.

21 5. PDS DEVELOPMENT: BACKGROUND : Exxaro looks for technology to prevent collisions between vehicles and pedestrians underground. 6-month trial Collision Avoidance System (CAS) project run underground at Arnot 8- shaft. Results showed potential to prevent collisions between TMM s and persons. Decision taken to roll-out CAS (Proximity Detection System/PDS) to other Exxaro underground operations. 2013: Exxaro PDS task team did extensive investigations to find and adopt leading practice PDS technology for the Exxaro group. Result: technology from a global leader in mine safety solutions was identified, and a contract awarded by Matla Coal to implement PDS on their mine. PDS Specialist appointed for implementation.

22 5. PDS DEVELOPMENT: MATLA 5-YEAR INCIDENT ANALYSIS 21 5-YEARS ( ) INCIDENT ANALYSIS CONDUCTED TO IDENTIFY HIGH-RISK MACHINES

23 5. PDS DEVELOPMENT: MINING INDUSTRY 5-YEAR INCIDENT ANALYSIS 22 5-YEARS ( ) INCIDENT ANALYSIS CONDUCTED TO IDENTIFY HIGH-RISK MACHINES

24 5. PDS DEVELOPMENT: MINING INDUSTRY 5-YEAR INCIDENT ANALYSIS 23 INCIDENT ANALYSIS CONDUCTED TO IDENTIFY HIGH-RISK MACHINES

25 5. PDS DEVELOPMENT: PRIORITIZATION OF TMM S 24 Electrical and Battery TMM s (Production Sections) Shuttle Car Continuous Miner Battery Scoop Roofbolter Tractors MPV LHD Underground Diesel TMM s (Backbye) Chock Hauler

26 5. PDS DEVELOPMENT: MAGNETIC FIELD RANGE 25 10kph STOPPING ZONE 20kph WARNING ZONE

27 5. PDS DEVELOPMENT: PDS VIDEO 26

28 5. PDS DEVELOPMENT: CURRENT STATUS 27 PDS (CAS) Development: Compliance to Regulation (a) and (b): Strata system incorporated. Not yet standard on the tractor. Awaiting final certification. Trailer PDS connection-box available.

29 6. CURRENT DESIGN 28 Current Equipment Features: FRAME: Sheet-metal fabricated frame. Short wheelbase. 400mm ground clearance. Replaceable bumper tips. Retractable / removable front tow hitch. Ventilated ROPS/FOPS cabin. Manual fan and 3 windows which can be opened. 2 Doors + 3-seats (high-seam); 2 Doors + 2-seats (low-seam). GENERAL: Improved bonnet visibility. Improved bonnet ventilation. Improved dashboard instrumentation and layout. PDS compatible. MAE electrical system with 6 remote adjustable LED lights.

30 6. CURRENT DESIGN 29 Current Equipment Features: FAILSAFE BRAKES: Rear-mounted Spring-applied, air-released Easily accessible Easily maintained Easily inspected Fully SANS 1589 compliant Passed brake performance test at Gerotek at high level Excellent reaction time PTO: Mechanical PTO engage with wet clutch Drive trough Torque Convertor Over-run protected and shearing pin kw power (required for high seam stone dusting above 4m)

31 6. CURRENT DESIGN 30 Current Equipment Features: TRANSMISSION: Gear ratio s good for towing heavy loads Semi-Auto 4-speed power-shift action Improved cooling ENGINE COOLING: 6 core radiator Improved fan Ventilated bonnet Corrected fan speed and fan pitch Improved cowling

32 7. THE WAY FORWARD Future Development Objectives: Tier 3 engines. More powerful engines. Dry scrubber systems. Chassis that can split and extend telescopically to make accessing the drive train even easier. Full PDS compliance (regulation ). Fully automatic gearbox. Cameras to improve visibility Fully hydraulic, no pneumatics, if required...

33 8. QUESTIONS 32