This column has never had the highest regard for most of the exploration companies on the Irish market.

There are exceptions of course and some have actually got to the stage where they are generating revenues. But for every Tullow or Ivernia there is another outfit trying to scratch a living from oil or minerals prospects in some part of Siberia, the Andes or Africa.

These are the sort of companies that anybody goes near at their peril. It's all very well investing in companies like Arcon or Ivernia, where the fruits of their labours - like Galmoy or Lisheen - are self-evident, or the likes of Tullow, which has an established record of making profitable oil and gas investments.

But when your money is going down a well in the Bolivian altiplano or down a hole in the steppes of Russia, one needs to be a bit more careful.

Navan Mining now looks as if it's joining the ranks of the higher quality exploration companies with last week's announcement of a potentially high-quality gold discovery in Bulgaria.

Add in the investment by Fleming Mercantile for a 3 per cent stake and Navan's share price has taken on a much rosier hue.