Shares in exploration group Pan Andean plummeted on the London stock market following the revelation that the company's joint venture in Bolivia with the Australian group BHP is to be broken up.

In thin trading on the Alternative Investment Market it fell 16 1/2p to 32p although trading in the shares were very thin, involving less than, 100,000 shares. At 32p, Pan Andean is now trading at an all time low and any recovery in the share price will depend on the group's ability to attract a replacement joint venture partner when the agreement with BHR.

Pan Andean had been seeking changes in its joint venture agreement with BHP but failed to reach agreement. As a result, ownership of the Chapare block in Bolivia will revert 100 per cent to Pan Andean and the Irish group will also take possession of drilling and geophysical data that has been accumulated at a cost of $30 million (£19.8 million).

Pan Andean intends to hold discussions with prospective joint venture partners once the BHP agreement ends at the beginning of July.