Raiblocks is a minerless currency. All coins that exist and will ever exist were created in what is called the "genesis account". These were later freely given via faucet for a period of time until the supply was exhausted. If you'd like to learn more I recommend going to the website: https://raiblocks.net/ and reading the whitepaper. Also checking out the founder's recent AMA at the subreddit could also provide a lot of valuable info!