A historical mass grave of hundreds of former miners have been found in the Bolivian mining town of Potosi.
The remains were found during construction work, according to the ABC.
"We are talking about a common grave found at about 1.8 metres, and the human remains are scattered over an area of 4x4 metres," Tomas Frias University researcher Sergio Fidel said.
The construction workers have found between 400 to 500 remains, although they believe there may be more.
It is believed the site was the burial ground for slaves and indentured servants who worked in the mine, or the remains of those killed during a massive accident in the town in the 1600s.
The mine is apparently one of the most dangerous in the world, and the city itself was last month placed on the UN World Heritage list as in danger due to the region’s uncontrolled mining.
Even today, on average the South American mine experiences a major accident every day, with at least three of the approximately 12 000 miners killed every month, mainly due to tunnel collapses and/or toxic gases.
After the Spanish discovered silver in Cerro Rico (Rich Hill) on the outskirts of the city in 1544, Potosi grew into the largest and most opulent city in the Americas, with a population that exceeds 200 000 people.
When Australian Mining visited the mine our guide and translator, Maria Joaquino, explained that the miners chew large quantities of coca leaves (as observed by the huge bulge in their cheeks) due to the nature of their work, and many miners were drunk on 98 per cent proof alcohol as well
"Firstly, it helps with working at altitude, secondly because it absorbs some of the airborne toxins, and lastly, it reduces their appetite which is beneficial because miners do not eat for the entire 12 hour shift that they work."
She explained there are no toilets in the mines, and advises visitors to avoid licking their fingers because of the trace elements of asbestos and arsenic found in the mines.
Joaquino went on to say most miners earn around $10 per week, "but slightly more for the dynamiters".
While the working conditions of this mine are shocking by today's standards, during the period of the New World Spanish Empire they were described as horrendous.
At first the Spanish masters used indigenous labourers in the mine, but as they were dying by the thousands, subjected to brutal working conditions and poisonous mercury vapours used in the mining process, the Spanish governors began importing African slaves to the mines to supplement the native workers.
These so-called 'human mules' also perished due to Spain's feverish desire for silver.
A life expectancy of less than one year was reaping a terrible human cost; mercury poisoning, mining accidents, exposure, and lung disease were all contributing factors.
Once sent into the mine very few ever saw daylight again.
Overall, it is estimated over eight million African and indigenous workers died in the Potosi mines during Spain's colonial reign.
To see a gallery of images from the Potosi mine tour, click here.
Image: A. Sandoval-Ruiz [Unesco]