Enabling Operation Of Opencast Mine During Rainy Season

Challenge Details

In our Opencast mine Shovel-dumper combination is used for excavation of overburden and ore. During rainy season, due to nickli-ferrous-limonite [approx. 40-50 LCM (Loose Cubic Metres)] present in the overburden material, the haul roads (Length x Width: approximately 100 km x 20 m; working length in monsoon: typically 20-25 km) become too slippery, making it difficult for dumpers (35 MT/50 MT) to maintain operation under control and ply normally. Additionally, the dumper operation on unstable slope causes damage to the tyres, which results in the increased load on the maintenance work. Keeping the safety precautions in line, the movement of equipment is stopped during rain/drizzle. This leads to productivity loss during rainy season. To continue the operations during rainy seasons, haul roads are covered with morum/quartz/HUB. These material(s) are overspread manually on the haul roads.  

However, this method is not sustainable owing to

• non-availability of sufficient quantity of material for covering,
• frequent changes in the layout of haul roads, as new faces (inclined slopes adjoining the benches) are being developed and operated.

Additional factors affecting safety of the haul roads are:

• Jet of water washing down the benches, during rainy reason, washes down the slippery material (mostly consisting of nickli-ferrous-limonite) on the haul road, this sticks and keeps on accumulating on the chains, tyres and adjoining portions of Dumper. Consequently, the grip of the tyres reduces causing unsafe plying conditions
• Making drainage facilities (for rain water) is not possible in the mines and this leads to piling up of materials that are slippery in nature

Therefore, we are looking for solutions, which will facilitate the movement of mining equipment and normal operation of mines during rainy seasons

The solutions must meet the following requirements:

1) It should allow mining operations during drizzle/rain/downpour

2) All chain/tyre mounted mobile equipment shall be able to move on the haul roads

3) Shall comply to mining statutory requirements

4) Shall be economical

5) Shall not hamper mining during non-rainy days

6) The suggested solution should facilitate/sustain the movement of mining equipment such as shovel/dumper/dozer/Grader

Additional information about the surrounding nature of soil

• Limonite: RMR (Rock Mass Rating) <10>
• Surpentinite: RMR< 5>
• Dolorite: RMR very less, Circular Failure in rainy season
• Hard Hub: RMR> 15, Prone to tyre cut

Additional information about the machines/vehicles moving on the haul roads

• Excavator (BACK HOE),
• Dumper (30t), Grader (35 t), Loader (40t) and Dozer (50t)

 You may like to refer to this link for more details: https://www.australianmining.com.au/features/the-nickel-laterite-challenge/