Advisory services firm Ernst & Young has reported that its index of the biggest 20 mining firms on London's Alternative Investment Market (Aim) soared by 47% during this year’s second quarter. The rise is attributed to a recovery in base metal prices.

Nevertheless, Ernst & Young stated cautiously: "Confidence in the junior mining sector on Aim appears to be making a return, but uncertainty remains the prevailing factor. The economic and market conditions continue to stress the have/have-not cash divide between junior mining companies. While some companies remain necessarily focused on short-term survival, others are shifting their strategic focus toward pursuing new opportunities for growth."

Since the beginning of the year the index has soared by 89%. However, it has still declined 57% from last March’s record high, due to a rise in metal prices from China, the world's top consumer of many industrial metals.

A copper and gold explorer and developer in Kazakhstan, Frontier Mining, reportedly made the biggest recovery with its share price leaping by almost 1000% during the second quarter.

According to the advisory firm’s report, five mining firms delisted during Q2 and no new companies joined Aim for a third consecutive quarter, thus reducing the number of mining firms to 168.