To meet the requirement for huge production of iron ores and removal of waste rock in much higher quantity from deep opencast mines, a compatible fleet of equipment has been developed and now is being used. Roller cone drill rig of bit dia 320 mm has been developed and deployed for drilling at flexible angles of 45 – 75o for smooth blasting. On the basis of satisfactory results from rigs, higher capacity rig of bit dia 400 mm has been developed. Their productivity exceeds that of the existing rigs by a factor of 1.5 due to automatic control of drilling. Another module of roller cone drilling rig has been developed and preliminary trial results showed increased drilling rate by factor of 2.5 – 3 and reduction in power consumption by factor of 1.5 – 2.0.
The most vital activity in opencast mines is the extraction and loading operations which need, for iron ore mining, shovels. Different types of shovels manufactured in the CIS are in use including hydraulic shovels. These are the world class products so far s operating cost and service life are concerned. In the CIS, loading equipment, namely ‘Uralmash’, Izhorsky Zarod” and “Krasmash” are specialised excavators for ferrous metal opencast mines. Bucket capacity of these shovels is 12 to 16 cu m and boom/arms can be extended for heavy and tough working condition.
As the transportation expenses at some mines is 60 percent of total mining cost, one of the thrust area of equipment development goes to this field. From the experience gained over the years, it is concluded that effective transport system is the judicious combination of railway transport, trucks haulage and conveying. In the CIS opencast mines, certain characterisations have been attained and these are large – scale production, favourable ecological condition and relatively low transportation cost. The main trends in the opencast mines are :
1. Improvement of facilities already available as well as development of new ones, such as locomotives and self – cleaning cars which will provide high technical levels and efficiency of mining operations;
2. Technical requirements of transport systems for deep opencast mines.
3. Using railway transport at deep levels of existing open-pits (up to 350 – 450 m depth) by introduction of heavy gradients and in pit tunnels. Locomotives of 450 tonnes are required to be manufactured in that group of countries as their application in deep opencast mines will result in increasing the rolling stock productivity by 20-23 percent, improving a conveying capacity of transport inclines by 20-25 percent and decreasing power consumption by 5-7 percent. Further, in the CIS carriage, wagon factories are going to manufacture the reinforced self-closing cars with capacity in the range of 105 – 200 tonnes.
In Russia and Ukraine, where diesel locomotives were traditionally in use, now electric locomotives of higher traction force are replacing them. This substitution results in increase of the railway transport efficiency, expanded field of application, reduced fuel consumption, and improvement of ecological conditions at opencast mines. Construction of in-pit tunnels and inclines has augmented the application of electric locomotives further. Locomotives are being used in inclines having grade up to 50 – 60o. A tunnel in a particular mine, allowed the railway transport up to 280 m depth to have reached to the pit bottom. Further, off highway trucks of 75- 110 tonne capacity are being commonly used in deep pits, but 120 – 180 tonne capacity trucks are also now deployed. In the CIS, now multi – drive conveyors are also developed and are in use.
The main advantage of this system is that rock mass can be transported from deep levels to surface without rehandling. Further, high inclination conveyors upto 45o are developed, which can handle/transport up to 2,000cu.m/hr. In the CIS, high capacity crushers (over 2000 cu.m/hr) are being manufactured at present.