Underground » Roadway Development
This Brief summarises the development of the Fan Trolley and Material Trolley. The project was sponsored by Springvale Colliery, in association with Illawarra Conveyor Services, Wollongong
Springvale Colliery had a requirement to provide auxiliary ventilation across the longwall face in order to mine past a fall in the tailgate zone. As a belt conveyor structure was already installed, it was proposed to mount a fan on the conveyor structure and move the fan outbye with the face retreat, keeping the auxiliary fan the required distance along the gateroad.
The aim of this project was to develop a set of equipment capable of supporting "Pantechnicon" type equipment and a set of equipment capable of transporting materials along the belt structure. These materials would support the longwall retreat system or roadway development.
The project essentially consisted of five stages.
Investigate the Load Carrying Potential of the Belt Conveyor Structure
The objective was to confirm by calculation and physical testing the practical loading that could be applied to the existing structure. Two bays of the 1200mm belt conveyor structure in use at Springvale Colliery were assembled and tested with 1200kg suspended along the troughing idlers to simulate coal and belt mass. An additional 3800kg was added to the idler centres of the stringers across the two bays. Measured deflection of the stringers fell within Australian Standards acceptances.
Design and Manufacture of a Fan Trolley
The design of the fan trolley needed to be such that components could be used and adapted to other applications. For this project, Springvale required an 18m3 Howden ventilation fan to be transported along the maingate, on the conveyor structure. The trolley was designed to use eight wheels mounted on four bogie arms. The bogie arms were centre pivoted and attached to two axles. The axles were then attached to a chassis that was purpose built for the fan. The trolley also employed a three point suspension system.
Mounting the Fan on the Belt Structure
The components of the fan trolley were manufactured, assembled and then attached to the chassis. A separate trolley had to be designed and built for the fan's starter box to also be mounted on the belt structure. The starter and fan trolleys were linked by two stiff arm linkages, long enough to provide room for the ventilation duct to be attached to the fan.
The fan trolley was taken underground and assembled on the structure outbye of the longwall maingate. The fan was stabilised using legs set between the floor and the roof. As the longwall was retreated to a planned position, the fan was operated to provide exhaust ventilation through special ducting across the longwall face. As the longwall was retreated to a planned position, the fan was moved 100m outbye along the belt structure using a winch system. Once the move was complete, the fan was again established and used to ventilate the longwall face.
Development of an Air Hydraulic Drive System to Allow the Trolley System to be Self Propelled
After the successful operation of the trolley system, it was decided to examine incorporating a drive system to make the fan trolley (and any other trolley developed in the future) self propelling.
The designed drive system incorporated an air/hydraulic power unit that would provide hydraulic power to a set of motors attached to the wheels of the trolley. The system also included a failsafe braking system.
Thirty metres of 1500mm belt structure was setup for the testing of the fan trolley drive system. The design called for the fan to be able to negotiate a 1:10 incline as well as a maximum structure elevation misalignment of 100mm across the structure and up to 420mm over two bays longitudinally. The results of the tests are listed overleaf.
| Maximum Tramming speed | Level -20m/min 1:10 Incline - 10m/min 1:10 Decline - 22m/min |
| Stopping distance (from 22m/min) | 100mm in 7sec (deceleration = 0.524m/s2) |
| Driving on wet stringers - Negotiating a 1:10 incline with stringers wet with water, coal dust, mud. | Trolley climbed incline satisfactorily. Trolley trammed down gradient and stopped satisfactorily |
| Creep Test - Trolley left parked on a incline for 1 hour. | The trolley did not move over the course of this 1 hour. |
| Braking Force of the system (max). | 12kN |
| Braking Force required (max). | 2.352kN |
| Driving Force of the system (max) | 11kN |
| Driving Force required (max) | 4.7kN |
Entrapment/Captivation
In order to guard against dramatic changes of alignment along the structure, and any situation where articulation was exceeded beyond permissible ranges, a system was needed to captivate the trolleys on the structure.
The captivation system does not lock the trolley to the structure, rather it stops the trolley wheels being able to leave the stringer. This was achieved by bolting purpose designed brackets to the bogie arms that would come into contact with the outer side of the stringer thus limiting the movement of the trolley on the structure. If a wheel did come off the stringer, the bracket would act as a catcher.
With the system proven to its current stage, it was then decided to design and build a trolley capable of carrying a wide range of materials and equipment.
The final design used the same axles, bogie arms, wheel hubs, wheels and drive bosses as the fan trolley. By using this equipment the same brake/motor drive units could be used thus making the parts interchangeable. This also meant that the mine would not have to carry a wide range of spare parts for the trolley. The final flat deck design was made 1800mm wide x 3500mm long and had a minimum deck height of 1350mm from the floor.
Outcomes
The main outcome of this project has been the utilisation of the previously wasted space above the conveyor belt. The project has proved that the trolley system combined with the structure can be used to move substantial equipment and supplies along a gateroad or development panel belt.
In trials at Springvale Colliery, the following benefits were seen:
- Improved overall belt installation standards
- Less people required to move materials (the fan) and reduced likelihood of damage to materials (the fan)
- Minimisation of disruption to maintenance activities and service moves
- Moving of fan is independent of the boot end location
Other foreseeable benefits include providing a known location for tools, equipment materials and spare parts. With these items mounted on the structure they would be less vulnerable to damage.
There is significantly potential for this equipment to improve mining systems. Use of this system may improve productivity by decreasing the amount of time spent moving services and equipment, thus increasing time spent cutting coal.
The final report includes considerable detail on the trials undertaken and the resultant trolley design.