Zambia's mining minister Richard Musukwa announced an investigation on Thursday after 10 people died during the collapse of a mine dump in the country's copper-producing region. The subsistence miners were killed on Wednesday when the dump known locally as Black Mountain collapsed in Zambia's second-largest city and mining hub Kitwe. Musukwa told parliament "the investigations are still underway and we have suspended operations at the Black Mountain to allow for a forensic investigation". Musukwa blamed the incident, which also left seven people injured, on "people who should not have been in the mine", describing them as "illegal miners or scavengers".Local media reported that ministers were forced to step in last month after small-scale miners at the site began using explosives to extract copper from the mine dump, damaging nearby properties and possibly dislodging the mound.Zambia has some of the world's largest copper reserves and the metal accounts for as much as 80% of the country's export earnings. Growing demand for copper has seen prices spike above $3.14 for a pound, according to the InfoMine service.This has contributed to a surge in illegal mining activity in Zambia which is beset by high levels of unemployment.Communications and power cables have become a valuable target, both for major gangs and small-time thieves both in Zambia and worldwide.* Sign up to News24's top Africa news in your inbox: SUBSCRIBE TO THE HELLO AFRICA NEWSLETTERFOLLOW News24 Africa on Twitter and Facebook.