Shares in Polo Resources climbed after the mining investor reported upbeat drilling results from a Tunisian phosphate project in which it has a 33.2% stake.Polo's stock lifted 0.8p or 12.9% to 7p at 14:59 in London after it said drilling to date by Celamin Holdings at the Chaketma scheme had hit thick mineralised zones containing grades of phosphorous pentoxide of more than 20%."Independent metallurgical studies have verified the potential to produce marketable concentrate acceptable to international offtakers," the group said in its results for the 12 months to 30 June.Polo also said the Tschudi open pit copper project owned by Weatherly International, in which it holds a 7.06% stake, was set to enter production in the second quarter of next year.However, the group said its Nimini Holdings business had been forced to temporarily stop activities at its Komahun gold scheme in Sierra Leone due to the ebola outbreak.Executive chairman Michael Tang said: "The year under review has been one that has seen Polo significantly strengthen its balance sheet and cash reserves from our oil and gas investments."As we head into the next reporting period, with an expanded portfolio which includes exposure to near term cash generating investments, Polo remains strong in the face of challenging price and market volatility."Polo posted a post-tax loss of $19.1m, significantly attributable to prudent provision against the Sierra Leone gold project of $28.2m and goodwill write-off of $2.8m, following the ebola crisis and weak gold-price outlook.