Deep inside a forest, sweating men haul earth out of rough excavation holes and carry it in bags on their backs to a stream.Then they sift for the small, red stones that could make their fortune - miners say they have sold single rubies for thousands of dollars, many times the local monthly wage which is typically under $200.In northern Mozambique, informal - and illegal - ruby mining is a tough business that has attracted thousands of itinerant workers despite strenuous crackdowns by police and private guards.The ruby deposits, which were discovered only nine years ago, are relatively accessible in shallow ground, triggering the sudden birth of a frantic wildcat mining industry.Mozambique now accounts for 80% of global ruby production - but the illegal mining is a far cry from the giant mining companies and the chic auction houses in Singapore where millions of dollars of gems are sold."I'm here because of poverty," Faque Almeida, 46, who has spent much of the last eight years in the forests of Montepuez in search of the blood-red gemstones, told AFP.He said he left his home province of Nampula, 400km south, unaware that it was illegal to look for rubies in Montepuez district after the government sold the rights to a large mining company."I was unemployed. When I left my home, I thought that breaking into the owner's door is a crime, but I did not know that digging the land is also a crime," said Almeida."Last year I was arrested, I stayed in jail for 14 days. I was released when my family paid 14 000 meticais ( $240) to the police," he said, holding a pickaxe in one hand.Montepuez Ruby Mining (MRM), a subsidiary of London-based Gemfields, won the mining rights to 36 000 hectares of ruby-rich land in Mozambique in 2011. 'I've lost many friends' The arrival of the British mining firm saw the authorities and an army of private security officers swoop down on the area and the hundreds of illicit miners known as "garimpeiros"."Sometimes holes collapse and fall on top of us. I've lost many friends and a brother here. But the biggest problem is the police and security guards," said Fernando Zulu."They come, arrest us, torture us and even bury our colleagues in the holes."Our demand is that the government authorise us to dig, extract the rubies and sell them to the government."To evade the authorities, miners like Zulu have retreated deeper into the forest, hours on foot from the nearest road.* Sign up to News24's top Africa news in your inbox: SUBSCRIBE TO THE HELLO AFRICA NEWSLETTERFOLLOW News24 Africa on Twitter and Facebook. Miners sleep in makeshift huts for weeks in search of a sizeable stone which, if found, is immediately taken to the nearest village.There it is sold to foreigners including Senegalese, Malians or Nigerians at the start of the illegal chain of trading."I buy the stones and resell. I don't think I'm an illegal migrant, I'm on my continent," said Senegalese gem reseller Amadou Wantaka.The stones then end up in the hands of bigger dealers from Thailand, South Asia or Vietnam.Violence against the miners, which has allegedly cost numerous lives, has been closely documented by observer groups but police and Gemfields categorically deny any involvement.Gemfields CEO Sean Gilbertson told AFP that "the relationship between our security men and the illegal miners is not necessarily friendly, but we do everything to respect the human rights of illegal miners".He said there had been a few "very worrying" cases of police or guards being bribed to allow illegal mining but the number was limited and guards now wore body cameras to ensure good conduct.And he stressed that legal mining generated million of dollars of tax revenue for Mozambique - in contrast to illegal mining.Augusto Guta, police spokesperson in Cabo Delgado region, insisted all police operations were safe and legal.Cassiano Johane left his hometown Lindi in Tanzania 650km away in 2011 to head to Montepuez in search of rubies."I have found stones several times and after selling them I send the money to my family," he said.But Johane's life in Montepuez has been as harsh as that of all illegal miners."I was detained once in 2011, taken to Pemba prison for five months. I was badly beaten by the police," he recalled. 'Stones that God gave us' After being released, Johane was deported to Tanzania. Just months later he crossed the border again.As well as forcing illicit miners away from the ruby-rich area, the police are accused of profiting from the game of cat and mouse they play with the stone-diggers."We talk to the police and they free us in return for payment," said Leonardo Vaneque, 23, who has been mining illicitly for eight years.Guta, the police spokesperson, denied the allegations.Mining Minister Max Tonela acknowledged that illicit mining and smuggling is damaging the country's development, and vowed "to reverse the current pernicious situation."But illegal miner Luis Elias, 42, said he had to continue scouring for rubies whatever the cost."We have no choice," he said. "We will continue to 'steal' the stones that God gave us."