On the go and no time to finish that story right now? Your News is the place for you to save content to read later from any device. Register with us and content you save will appear here so you can access them to read later.
The tuskers use powerful pumps, designed for firefighting, to blast into the earth and reach the buried remains.
The recent rush for the "white gold" has made millionaires out of some residents of Siberia's poorest villages, where "agents" act as middle men between tuskers and their wealthy buyers.
Sculpted tusks regularly sold for more than $1 million each.
There were also lucrative markets for the remains of other animals: horns from woolly rhinos, which typically end up in Vietnam to be ground into powder and then marketed as medicine, also sold for tens of thousands of dollars each.
Tuskers risked small fines, but serious charges if caught more than three times.
Warnings of "greenie patrols" - boats with environmental-protection officers accompanied by police - sent the tuskers scurrying into the bush, before a watchman gave the all-clear over a walkie-talkie after the boat had passed.
Chapple said the illegal nature of tusking naturally made it difficult for him to gain exclusive access.
At first, he tried to blend in among the men by doing odd-jobs, before he was confident enough to start taking pictures.
Some reacted with hostility, stopping him on trails and questioning him.
"There were 60 or 70 guys out there, so what I was doing, journalistically, was quite tricky."
Tusking was polluting the region's rivers, clogging them with silt and slurry from the tunnelling, but the bigger concern was with the damage to Siberia's ancient artefacts.
Chapple had witnessed tuskers, with hands wet with fur and hair, casually discarding pieces of animal hide to get to the tusks.
"I spoke to the manager of the mammoth museum in the region's big city, and he said, 'You come to me with questions about the environment? Paleontological treasures are being destroyed'.
"The reality is that so much is being lost."
He planned to approach major news outlets with his pictures to raise more awareness around the issue.