The mineable reserves have been calculated after deducting quantities from the geological reserves due to the restrictions to work above the water table to prevent deterioration of ground water quality. From the reserves, a loss is assumed on account of pit slope maintenance and leaving a 7.5 m corridor along the lease boundary. The total reserves of the deposit are 103.42 million tonnes and the mineable reserves are 74.47 million tonnes. This estimation of limestone reserves of the Babarkot lease has been based entirely on actual exploration data, a strip of 60 m from the seafront being excluded front the estimation. Also, only the ‘in situ’ reserves above the mean sea level have been taken into account. The reserves have been calculated following the standard cross-sectional method.

The block wise break up of reserves in the lease area is given in Table 3.1.

Table 3.1. Category-wise updated reserves as on 1.4.2005.

In the Babarkot North block the total reserves under Proved category is 26.56 million tonnes. Out of which the reserves of marl is 9.02 million tonnes and the reserves of limestone is 17.54 million tonnes.

In East block, after re-estimation of reserves leaving a distance of 100 m from the cliff edge, total reserves stand updated to 69.23 million tonnes as against previous total reserves 80.76 million. As of now proved reserves in East block are 45.88 million tonnes out of which the reserves of marl are 5.05 million tonnes and the reserves of limestone are 40.83 million tonnes.

About 253.60 ha area of the mine lease falls within 500 m of high tide line forming part of the CRZ. Due to the promulgation of the CRZ Notification which prohibits mining in 500 m wide Coastal Regulation Zone nearly 37% of the mineable reserves of superior grade limestone have been sterilized. NCCL filed a petition (SCA No. 4852 of 2003) in the Gujarat High Court challenging the applicability of the Coastal Regulation Zone (CRZ) notification to its mining leases which were initially granted before the promulgation of the CRZ notification. The Division Bench of Gujarat high Court passed an interim injunction order on 22.04.2003 restraining the Respondents (Union of India and others) from taking any steps pursuant to CRZ notification, as amended, to prevent the company from conducting mining activities in the entire area falling within its mining leases. The present position of reserves excluding the CRZ area is given in Table 3.2.

Table 3.2 Reserves excluding CRZ as on 01.04.2005.

Out of the above proved reserves, nearly 14.53 million tonnes of reserves become redundant in the absence of blend component of superior grade limestone from the CRZ area in East block. Therefore, the usable reserves are as under:

Table 3.3 Breakup of usable reserves in the lease area.

The quality of limestone in the area exhibits distinct lateral as well as depth variation. The quality of limestone beyond CRZ is mostly cement grade with limited of patches of superior grade (+ 47% CaO). Further, in the North block, the lower level deposit is mostly inferior limestone/marl, having presence of free silica as compared to the upper level limestone.