NEW DELHI: The world's largest coal miner CIL today reported a 13.9 per cent increase in consolidated net profit at Rs 3,718 crore for the quarter to December on the back of higher sales.Net profit came in at Rs 3,262.5 crore in the same quarter of the previous fiscal, Coal India (CIL) said in a filing to BSE Net sales during the reporting quarter stood at Rs 18,971.5 crore, an increase of 6.8 per cent yoy.However, total expenses increased to Rs 15,407.5 crore, compared with Rs 14,850.1 crore in the corresponding quarter of 2014-15.On a stand-alone basis, net profit (after taxes minority interest and share of profit of associates) of the state-owned firm declined to Rs 672.6 crore as against Rs 695.8 crore in the year-ago period.Total income from operations declined sharply to Rs 36.2 crore, from Rs 74.6 crore a year earlier The company further said a joint venture company -- Rashtriya Coal Gas Fertilizers Ltd -- was incorporated in November last year through an agreement among CIL, the Rashtriya Chemicals and Fertilizers Ltd, GAIL (India) Ltd and the Fertilizer Corporation of India."The JV company has an authorised share capital of Rs 50 crore, of which CIL shall hold 26 per cent," it said, adding that there had been no investment in the JV up to December 31.Its output in April-December of the current fiscal went up to 373.5 million tonnes (mt), from 342.4 mt a year ago.Coal India accounts for over 80 per cent of the domestic coal production.The stock of the company closed at Rs 305.05 on BSE, down 2.87 per cent from the previous close.