I don't know how it works with mining specifically, but in general: grin payments require a three-way process. This can be done automatically through an IP address or keybase, or you can do it manually like this:
1. The sender runs grin wallet send -m file -d FILE.txt GRIN_AMOUNT, which creates the file FILE.txt.
2. The sender gives FILE.txt to the recipient.
3. The recipient runs grin wallet receive -i FILE.txt, which creates another file FILE.txt.response.
4. The recipient gives FILE.txt.response to the sender.
5. The sender runs grin wallet finalize -i FILE.txt.response, and the transaction is done.
The IP/keybase methods do these same steps, just automatically.
I'm not going to be mining, but I would like to buy some grin ASAP on the first day. If anyone here is lucky enough to quickly mine some, I'll pay $13/grin (in BTC), but only for the first few grin I buy. PM me.
Cheers, looks like peeps are definitely ready to mine, hopefully the main pool can take the load !