This Mar. 20 report in Copper Investing News said the recent spike in copper prices may be due to a work stoppage at the Grasberg copper mine in Indonesia. The Grasberg mine is one of the largest in the world. Said the report:
“Copper investors were likely pleasantly surprised looking at price charts at the end of this week. After plummeting near the start of the year and sitting around $2.60 per pound for the past month, the metal’s price appear to be heading up.
“According to Bloomberg, about 50 mine workers have blocked road access to Grasberg for the fourth day in a row. Output from the mine was suspended Monday, although the miner continued to make shipments from its inventories."
The 30-day Copper chart below from www.kitco.com clearly shows the spike in copper prices.