Blockchain use is the only similarity between DCoin and typical cryptocurrencies. As for the mining, more precisely, how exactly new coins are created, I’ve written in this article: - http://dcoin.me/en/story.html, you can also read more here - http://en.dcoinwiki.com/Promised_amount. You can learn more about how blockchain is constructed here: http://en.dcoinwiki.com/Block_Generating_Miner