Kumar Mangalam Birla, Chairman, Aditya Birla group proposed an investment of around Rs 7,000 crore on new plants and expansion of existing plants in Karnataka over the next three years.The investment is in addition to about Rs 6,000 crore the group has already invested in Karnataka. Birla announced the investment plans in state capital Bangalore.Of the Rs 7,000 crore, it would invest Rs 5,750 crore in new cement facilities and about Rs 1,160 crore in expanding its metal and chemical plants in the state.