Limestone is a low value, high volume, naturally occurring, bulk commodity and is a principal raw material for cement manufacturing. Limestone is geologically extracted through a mining process where almost all of it is captively mined and consumed by the Cement Industry in India. On average, each tonne of Cement requires approximately 1.1 tonnes of cement grade limestone. To meet such an enormous amount of raw material continuously, Cement Industry needs to operate in close proximity to limestone mines. Limestone occurs naturally at selective clusters in India and it is not possible always to set up a cement plant with adjacency to mines. In such cases, when limestone mines are at a considerable distance, delivery of limestone in an efficient, continuous, safe, quiet and economical manner tends to be a challenging task for the industry.
Conveyer belt networking is one of the best practices adopted prominently by the Indian Cement Industry for uninterrupted and hassle free movement of limestone from mines to Cement plants where both are at a reasonable distance apart. Over land Belt Conveyer (OLBC) systems are increasingly gaining popularity as they can traverse across difficult terrains, natural habitats, over streams and unstable ground without disturbing the local habitat. This ensures uninterrupted and continuous haulage of material in an environmentally and socially responsible manner.
OLBC offers several benefits compared to a conventional fleet of trucks to move the bulk material limestone. Some of the notable benefits are listed as follows2:
OLBC offers more safety compared to a conventional fleet of trucks in terms of preventing any possibility of road accidents due to movement across the populated area. Sometimes land route disruptions also call for significant detours of trucks, which are completely avoidable with OLBC having a fixed uninterrupted route.
OLBC systems can go anywhere across challenging terrains that are otherwise difficult for conventional vehicular mobility. OLBC can be designed to quietly move material across forest areas and over the streams without disturbing the natural habitat.
OLBC can run continuously with minimal downtime and regular maintenance. On the other side, conventional trucks may face mechanical breakdown, traffic congestion and other challenges, which hampers the overall logistics efficiency.
Material haulage trucks are typically heavy and consume a lot of diesel fuel, which adds to the environmental footprints of the industry. Depending upon the route, terrain and congestion, diesel truck emissions could vary each time. OLBC offers environmentally sound matter of moving almost any kind of material with far low emissions and without any chances of spillage.
OBLC require almost half of the manpower than required by a conventional fleet of vehicles. Remote monitoring is also possible with OLBC, which allows more flexibility and delivery efficiency.
In India, several Cement companies have adopted OLBC systems for the movement of limestone material from their captive mines to Cement production units. In each case, OLBC overcomes a different challenge and offers a fit for the purpose solution to the Cement Industry. Some of the distinguished examples from the Cement Industry are listed below:
This system is designed to carry 1500 tonnes of limestone material per hour covering a distance of 10.6 km from mines to the plant. On its way, it safely crosses a highway and a railway line and is operating successfully since 2005.3
This OLBC conveniently meets approximately 10,000 tonnes of limestone requirement through a haulage capacity of 1650 tonnes per hour. It ably negotiates difficult terrains including two hills and a valley. It is uniquely designed to transport material across a downhill stretch of 950 m and an uphill stretch of 1750 m with an effective lift of 270 m.4
This 21 km long OLBC system is probably the largest cross Country conveyer system adopted by any Company in India.5 It can transport 1000 tonnes of limestone per hour from a mining quarry to the end use Cement Plant. This conveyor system was commissioned in 2012 and safely travel through several villages, roads as well as across 120 m wide span of the Sonar river.
The Company has installed a 6 km long Over Land Belt Conveyor (OLBC) to source raw material from its captive mine to the manufacturing plant that further adds value in gaining cost and environmental efficiency.6OLBC passes through uneven terrain both Uphill and Downhill, crosses National Highways, Kacha roads, small canals, and rivers, Electrical lines namely HT & LT Lines, passes through trenches and several villages taking into consideration all safety aspects, norms, and government regulations. OLBC discharges material to the dump hopper located inside the plant. It saves more than 1557600 kg of CO2 emissions on an annual basis.
This 7.8 km long single flight OLBC system has a design capacity of moving 1200 tonnes of limestone per hour. It has two self propelled maintenance trolleys for the 3.5 MTPA capacity greenfield Cement plant.7