The current coin called (VEN) is an ERC20 coin. However, they will launch their own blockchain soon. I have read that it would be a fork of Ethereum.
Once that happens, they will have a special way for mining. for more info, please read this:
Thank you, @steemengines. https://medium.com/@vechainofficial/vechain-apotheosis-part-ii-thor-power-forged-974111a93278