Usha Martin will be investing Rs 1,200 crore over the next four years, P Bhattacharya, joint managing director of Usha Martin, said.The company is one the largest steel wire makers in the world. The investment would go towards the company's capital expenditure to enhance steel capacity expansion to one million tonne as well as value added product capacity enhancements. The one million tonne would be achieved in two phases, Bhattacharya said at on the sidelines of the company's AGM.The company today obtained shareholders' approval for raising up to $75 million by way of public issue, private placement, preferential allotment basis, along with an option to the lead manager to acquire up to an additional 20% equity shares or GDRs or FCCBs or ADRs.The raising of money was just an enabling resolution which would give the management more flexibility in choosing the right financing option, Rajeev Jhawar, MD of Usha Martin, said.Usha Martin aims to be the largest wire rope company over the next couple of years. The company had tied up backward linkages. Bhattacharya said, the iron ore mine was operational and coal mining would commence by the end of this year.