I love this mod and have been using it on my private 1.7.10 server. Only thing is, we notice that the minions disappear after a certain amount of time. You can see that work is still being done, but the minions themselves are invisible. I wouldn't mind too much, but this makes it difficult to get the resources from them. And they also don't always put the resources in a chest after I specify one. Right now the only way I can ensure I get all the resources back from them is to walk far away from where they were mining and call them to me, and then unsummon them so they drop their inventories. While this is doable, I think it would be great if the minions were more reliable when dealing with chests. Other than that, great mod!
Sidenote, I read here that some people also have the invisible minion problem, and seemed to imply that Optifine was the issue, but no one seemed to confirm this. I will try disabling Optifine to see if that fixes the issue. However, I would very much prefer to use Optifine, and would like to know if one of the settings could be toggled to get rid of this issue.