-Dinesh Dixit, General Manager (Mines) - Prabodh Singh, General Manager (QC) -Emami Cement Limited

Transcription

1 Utilization of limestone above Threshold Value with reference to limestone mine of M/s Emami Cement Limited at villages Kukurdih-Risda, Tehsil Baloda Bazar, district Baloda Bazar- Bhatapara, state Chhattisgarh- A Case Study By -Dinesh Dixit, General Manager (Mines) - Prabodh Singh, General Manager (QC) -Emami Cement Limited

2 Threshold Value of limestone: In the interest of systematic development of mineral deposits and conservation of minerals, threshold values of limestone has been notified as under, by IBM States CaO% (Min) MgO % (Max) Chhattisgarh, Gujarat, Himachal Pradesh, Madhya Pradesh Maharashtra, Rajasthan Uttarakhand, Uttar Pradesh 34 4 Andhra Pradesh, Jharkhand Karnataka,Kerala, Odisha Tamil nadu Mine Owners Responsibility: 35 4 Source: IBM Notification, T 45031/CGBM/2007/PF dated 16 th October, Separate stacking for Non-saleable, un-saleable / un-usable minerals above threshold values in the area earmarked for the purpose. 2. Maintain/ update quality and quantity of material above threshold. 3. Overburden and waste material obtained during mining to be stacked separately.

3 Emami Cement Limestone Mine: 1. Location of limestone mine: 1. ML Area Hectare 2. Villages Kukurdih and Risda 3. Tehsil Balodabazar 4. District Balodabazar- Bhatapara 5. State Chhattisgarh 6. Latitude 7. Longitude 8. Toposheet No. 64 K/ N to ' N ' E to ' E

4 2. Process of Identification of Limestone above Threshold value: To achieve the targets of systematic development of mineral deposits and conservation of minerals, scientific approach of identification of various category of limestone and reserve/resources is essential, ECL achieved this in following manner: Detail Exploration in the mining lease area at 150 x 150 mt grid interval. Bore Holes Drilled 172,maximum depth 100 mts, total meterage mt Core Recovery 95 percent. Sampling Sampling of core obtained from drilling at 1 mt interval to know the chemical constituents of entire rock mass, vertically. No. of Samples : 4296 samples generated and analyzed for 13 radicals i.e CaO, MgO, SiO 2,Al 2 O 3,Fe 2 O 3,SO 3,Na 2 O,K 2 O,TiO 2,P 2 O 5, Cl,LOI,MnO Statistical Interpretation of data generated from exploration. Categorization of reserves and Resources into Cement Grade (CaO 42.5% min) and Low Grade Limestone (CaO to +34%). Mine Planning as per the category of reserves and resources for optimum utilizations of material below Cut-off in cement making.

5 Limestone Reserve and Resources in Mining Lease: Category UNFC Code Cement Grade limestone Low Grade Limestone (as per Threshold Value) (Million Tonnes) Average Grade (Million Tonnes) Average Grade Proved Mineral Reserve Probable Mineral Reserve CaO %, MgO 1.71 %, SiO % TOTAL CaO %, MgO 3.42 %, SiO % The mining lease has huge quantity of limestone which is between cut-off grade and threshold value i.e it can be called as Low Grade/Marginal Grade

6 Utilization of limestone which is between Cut-off grade and Threshold value: ECL has searched various possibilities of utilizing this limestone in cement making: 1. By selection of best possible combination of Fuel along with limestone in cement making: Fuel GCV and Ash CaO SiO 2 MgO Fe Al 2 O 3 Pet Coke 7800 ( Ash 2%) Indian Coal 4700 ( Ash 30%) Imported Coal 5800 ( Ash 20%) The data suggest that use of Pet Coke some quantity of limestone which is below the cement grade limestone (cut-off 42.5%) can be utilized in cement making. The use of pet coke reduces the cut-off marginally to CaO percent instead of 43 % CaO which is most desired grade of limestone.

7 2. By Blending with the high grade limestone available in the mining lease: With the help of Surpac software ECL is able to blend 882,115 tonne Limestone, which is below the cement grade limestone in the mining plan period. Advantage: Reduction of waste generated from mining operation. 3 By Blending with the high grade limestone procured from other mining leases having High grade limestone as Sweetener (commercial mines) Advantage: Reduction of waste generated from the mining operation, increase in the life of mining lease. Disadvantage: High Cost of limestone to affect the cement price. 4. By Blending High grade limestone from import Advantage: Reduction of waste generated from the mining operation, increase in the life of mining lease. Disadvantage: High Cost of limestone to affect the cement price.

8 Inference: Emami Cement Ltd has carried out systematic assessment to identify the limestone according to the Threshold values and its possible usage in cement making and based on these studies, following inference can be drawn: 1. In the present day context, only small quantity of limestone between threshold and cement grade can be utilized in cement making. 2. The High grade limestone availability is limited in the country and hence it is not possible to utilize the limestone between threshold and cement grade completely in cement making. 3. The import of high grade limestone for blending purpose is possible only for those cement plants which are near to the coast. Moreover, the availability would be governed by the international policies. 4. The high grade limestone available from the e-auctioned mine would be of very high cost and would not be feasible for blending.

9 Suggestion: 1. Enhancement of Threshold value to 38 percent CaO: The utilization of 34 % CaO is not practically possible because the ratio of other radical in this low grade limestone is very high like SiO2 (19% to 20%), Al2O3 (5% to 6 %), Fe2O3 (4 % to 6%). 2. Use of OPC should be banned except in certain cases as clinker consumption for OPC is 95% of the cement. Accordingly use of blended cement will result in conservation of Cement grade Limestone. 3. With the use of latest innovation and technological changes cement industries are in a position to further increase the fly Ash consumption up to 40%, meeting completely or exceeding the strength requirements of BIS as per IS-1489 part-1. This will result in additional 5 % saving of clinker and ultimately 5 x 1.50= 7.50 % saving of Cement grade limestone. 4. In the present scenario, the applicability of beneficiation of Low Grade Limestone to be examined by way of various mineral processing techniques as per the mineralogy of Limestone. 5. Considering the dynamics of the cement market, feasibility of beneficiation of Low Grade Limestone need to be explored.

10 Suggestion: 6. Incentivize the cement companies for up gradation of low grade /marginal grade limestone through ore beneficiation process. An elementary study done by ECL indicate that it is possible to increase the lime content of marginal grade limestone having intercalation as clay from CaO 37 % to 45 % and reducing silica from 16 % to 12 %.

11 Address: Emami Cement Limited Village: Risda Tehsil Baloda bazar District: Baloda Bazar-Bhatapara (CG) Thank You

12 BACK-UP SLIDES

13 Results on various screen of Raw material taken from mines. Limestone Analysis Report of Raw material(-40mm) before Processing Sample ID LOI SiO2 Al2O3 Fe2O3 CaO MgO LSF SM AM Raw Material Sample No Raw Material Sample No Description VVR/LS/EMAMI/Sample-1 (-40mm+20mm) VVR/LS/EMAMI/Sample-2 (-40mm+20mm) VVR/LS/EMAMI/Sample-1 (-20mm+11.1mm) VVR/LS/EMAMI/Sample-2 (-20mm+11.1mm) VVR/LS/EMAMI/Sample-1 (-11.1mm+6.3mm) VVR/LS/EMAMI/Sample-2 (-11.1mm+6.3mm) VVR/LS/EMAMI/Sample-1 (-6.3mm) VVR/LS/EMAMI/Sample-2 (-6.3mm) Lime stone Analysis Report Belt Sample (-40mm)_After Processing at Nagpur IBM Sampling Point Date Chemical Analysis SiO2 Al2O3 Fe2O3 CaO MgO LSF SM AM % % % % % % % % Sample Sample Sample Sample Sample Sample Sample Sample

14 Cement Grade Limestone Deposit and Cement Production in India Total Resources as on ,935 Million Tonnes Total reserve as on Million Tonnes Remaining Resources - 170,009 Million Tonnes Total Cement Production in Million Tonnes Million Tonnes Estimated Cement Production by Million Tonnes At the rate of 550 M.T. production of cement the proved reserve will be exhausted with in 27 years Conversion of the remaining resources in reserves will suffice for about 300 years.

15 Presently BIS has introduced standardization of clinker as IS :2015 specifying the chemical and physical requirement of clinker in table 1 & 2 clause 5 & clause 6.1 of IS-16353:2015 Lsf requirement according BIS slandered to 1.02 C3S percent by mass Min 35 C3A percent by mass 3 to 12 C3S + C2S, percent by mass Min 70 Magnesia, percent by mass, Max 6.0