Hitesh Sukhwal, Senior Manager (Head Environment), JK Lakshmi Cement, breaks down the limestone mining process for us and expounds on the benefits of sustainable mining process and safety protocols.
How often does your organisation conduct the process of mining limestone? How is the raw material sent over for clinker production?
Cement industry is one of the main industries necessary for sustainable development. It can be considered the backbone for development. The production process of cement clinker is a continuous manufacturing process. Limestone is a primary ingredient and raw material for clinker manufacturing process, which is sourced from quarrying of limestone mine. Thus, the process of mining also plays a pivotal role for continuous production of cement clinker.
Limestone extraction is carried out by open cast mining, a fully mechanised method. Open cast mining mainly involves drilling and blasting. The planning part is an important aspect for the mine’s operation, apart from planning the shutdown, preventive maintenance schedule of machineries, peak rainy days, buffer stock etc. Mining limestone is a daily process for cement manufacturing. We adhere to the IBM and DGMS standard guidelines for mining.
The mined limestone is transported through dumpers to the crushing plant located in the Captive Limestone Mine Lease Area. Crushed limestone from the crusher is conveyed to the cement plant via covered conveyor belt/overland belt conveyor (OLBC) for further processing of clinkerisation.
What is the impact of limestone mining on the environment and the areas that surround the mining field?Â
Limestone mining is one of the important economic activities, which has the potential for contributing to the development of regional as well as the national economies. At the same time, the environmental impact of limestone mining is a major concern. Mining is undertaken as per an approved mine plan. All environmental parameters as per the norms of the Ministry of Environment, Forests and Climate Change (MoEFCC) are taken into consideration while preparing the mine plan. Since mining is localised to a few hectares area only, hence impact is negligible. The areas of concern are air, water and noise, which are monitored regularly while dust suppression is a regular process as per the guideline of DGMS as well as IBM. Impact on lease area is minimal.
What is the equipment used for mining by your organisation and where is that sourced from?
Limestone mining is carried out using the latest modern equipment controlled by our organisation. Basically, open cast mining involves drilling, blasting, loading, and transfer of material. Mining equipment viz. Drilling machine, Rock breaker, Backhoe, Loader, Tippers, Explosive Van and Water Tanker are deployed for mining.
What is the technology behind mining of limestone for the cement process?
The mining operations are being carried out by open cast fully mechanised methods. All operations of mining are being done by using high tech mining equipment such as drilling machines for deep hole drilling, blasting, excavation, loading and transport of material to ensure maximum mineral conservation and minimum environmental degradation. All the equipment are environment friendly with strict safety and adhered to emission norms that cause less environmental damage.
How can limestone mining be optimised?
The short-term and long-term planning plays an important role for quarrying of mine. The importance of each factor will depend on optimisation of mining operations viz. geology of area, quality and grade of limestone, locality, topography, distance, efficiency of equipment, maintenance schedule, production rate, quality check points, monitoring mechanism, mining methodology etc. Due emphasis is given for conservation of minerals and reducing rejects.
The mining area is selectively identified and all parameters towards reducing diesel consumption, less lead distance, fuel efficient equipment, separate dumps for rejects, dust suppression with less quantity of water (like fogging system), optimum utilisation of resources, working and calibration of cross belt analyser (cross belt analyser is an advanced process control and real-time optimisation solution) – are some considerations, which are always done while carrying out mining.
Tell us about the efforts taken by the organisation to make limestone mining a sustainable process.
Scientific estimation of reserves, planning of mining operations to increase the life of mine and conserve the ore with simultaneous reduction of rejects and exploring possibility of beneficiation of sub grade material are under consideration towards sustainable mining. Moreover, we are also focusing on production of green cement as per the market demand. Production of Cement like Portland Pozzolana Cement (PPC), Portland Slag Cement (PSC) and Composite Cement are the best possible solutions to increase the life of mine, reduce greenhouse gas emissions and boost the sustainability of cement business.
How does your organisation address the issue of noise pollution while mining and grinding limestone?
Operation of heavy earth moving machines and allied mining operations such as transport, workshop activities etc. may produce noise pollution in the mining area unless appropriate abatement measures are planned and effectively carried out. Control blasting at a fixed time helps to lessen the impact of high noise in the mining area. Noise levels are regularly monitored for equipment as well as crushers. It is ensured that the levels are well within permissible range. Adequate PPEs are provided to all workers operating in the high noise area. Compliance of all applicable norms and parameters ensured.
Following activities are being done for mitigation of noise pollution:
A. Sharp drill bits and wet drilling is being used to reduce the noise
B. The noise due to the blasting operation lasts for a very short period. Controlled blasting is being carried out with optimum charge using Air Decking Technique with wooden spacers and NonElectric detonator (NONEL) for control of noise, fly rock, vibration and dust emission.
C. No secondary blasting is being done. The boulders are broken by a hydraulic rock breaker. Ground vibration and noise level are being monitored for every blast by seismograph, which is also calibrated once in a year.
D. Ensure periodic maintenance (like oiling and greasing) of all HEMMs/other machineries.
E. Green belt development near mine lease boundary, crusher and best extent possible location to further attenuate noise level in mining area and its surroundings.
F. All employees are provided with PPEs (like earplugs/earmuffs).
G. Large equipment (like excavators, dumpers, dozer, drilling machine) and other automated equipment, which requires an operator are well equipped with soundproof cab.
H. Periodic noise level monitoring is being done for corrective and preventive actions.
I. Installed in-house designed rock breaker in Jaw Crusher to mitigate cracking noise generated during jamming of crusher.
How is the waste from the mining process managed? Tell us more about it.
In our mines, waste generation is negligible. We have adopted a mechanism of utilising the subgrade with proper blending so that high grade and low-grade limestone is utilised simultaneously, thereby helping in conservation of ore and reducing generation of waste. Separate dumps have been developed in the lease area as per approved mine plan.
What are the technological innovations the industry must incorporate to make the mining process more efficient and less harmful for the environment?
Overhead water spraying system installed on water tankers for haul roads, automated fogging system in crusher hopper and along the conveyors, water sprinkling along haul roads through designated pipeline fitted with sprinklers, belt conveyor system (covered) for transportation of material, are a few innovations that have been implemented. Control blasting with optimum charge using Air Decking Technique with wooden spacers and Non-Electric detonator (NONEL) is the best way for the mining process, which is more efficient and less harmful to the environment. Blasting is optimised through scientific study carried out by CIMFR, Varanasi to help in reducing ground vibration, noise and fly rock.
Stringent safety parameters as recommended by DGMS for all mining equipment should be followed to minimise environmental and safety hazards. Moreover, for sustainable mining, use of real time data analysis with the help of information technology would be the best way for mining operation, deployment of machineries, machine data analysis, lead time analysis, minimised work delays, conservation of natural resources and to increase life of the mine.
What is the future of mining for cement in India?
India is the second largest producer of cement in the World. Cement and Mining are a fundamental part of the Indian Economy. India has just emerged as a major player in infrastructure development and the future holds very bright prospects for the industry and the nation. During the Covid-19 pandemic, it is observed that Industries are willing to adopt emerging technology like Intelligent Automation for preventive maintenance to avoid sudden breakdown and to take timely corrective action before any trouble in the whole operation. An intelligent dashboard can give all information ready and timely for decision making. In the near future, artificial intelligence (AI) will lead all kinds of manufacturing industries. In the cement and mining industry, digital transformation will integrate with a lot of information and technological innovations to reduce time spent on machinery breakdown, preventive and timely maintenance, shift changing time, logistic network, lower cost of production, increase production efficiency and of course will cover regulatory compliance.
Automation in mining will reduce physical risks thus creating a safer environment. Involvement of IoT, satellite communication, automated water sprinkler system for haul road etc. are the best examples in mining. Through adoption of modern equipment, software for effective data analysis, latest communication technology and operational automation will change the entire scenario of the mining and cement industry in terms of lower operating cost, high yield, energy efficiency and lower GHG emissions industry. This will also boost the sustainable future of the mining and cement industry in India. In other words, we can say digitisation and sustainability will be the two buzz words for both the sectors.
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