Vantage Drilling received letter of award for Tungsten Explorer Vantage Drilling announced that it has received a conditional letter of award for its newbuild drillship the Tungsten Explorer to work in West Africa. The award is for a period of up to four years commencing in mid 2014. The contract has a minimum duration of two years, while the customer has four six-month options to extend the contract. The letter of award is subject to customary conditions including negotiating the final terms of the contract which is anticipated to be completed in Q1. The estimated revenue over the initial two year firm period of the contract is approximately $468M, including mobilization.