Hindustan Zinc Ltd. is preparing for a major capex programme as the Vedanta Ltd.-owned company aims to double its zinc output in the next three to four years.“I have already started an RFQ (request for quotation) inviting tenders... global tender for mining, mining designers and mining operators to work with me to see how 1 million tonne production can become 2 million,” Arun Misra, chief executive officer of India’s largest zinc pro...