This is a serious problem for me and many players.
If possible, the respawn rate of the fields need to be changed. It is too difficult as it stands now to completely deplete the field to get it to respawn, I have tried! Example: Mine a few pieces from a couple of green tiles, rescan, mine a few pieces from a smaller green tile, rescan. Maybe if I knew how much I needed to extract from the empty green field before it respawned would help.
I like what the devs have done to the mining experience but... I would think the mining experience should be "fun" for players but there is nothing to gain to make players hop around a mining field mining out little green tiles that bare no fruit for a player just to get the next field to spawn. I hope this is not the type of "miners code" they wish to relay.
Happy mining!