Tungsten Mining NL (ASX:TGN) is preparing for a initial public offering on AIM with a GBP 100 million valuation, the Sunday Times reported. Tungsten West is hoping to raise up to GBP 20 million in equity and a further GBP 40 million in debt, according to the Times, adding it is backed by former JP Morgan Chase & Co banker Ian Hannam and Moneysupermarket.com Group PLC co-founder Simon Nixon.