I agree with the person who said "ambushes everywhere", BUT, I know a potent blend.
If the mining town has large stocks of silver, I'd suggest creating Silver Azide: Basically, you mix ammonia, silver, and add in a gracious amount of lye in an unholy alchemical blend. It's ACTUALLY stronger than TNT...though pretty fucking volatile. Blast Globe equivalent.
Besides that, I'd suggest rigging the mining town itself. Get everybody as kitted up with ranged weapons as possible, and teach what you can to the militiamen. Besides that, slip back and do an insurgency. Druids are spellcasters: They're good for SHIT up close, provided you don't let them wildshape.
As such, have your militia guerilla warfare the fucking hippies. Have them wait in treetops with crossbows/bows and arrows as you use your unarmored speed bonus to draw the druids closer. They will NOT be able to cast with arrows raining down on them.
If the rogue/Warforged are trying to get up in your face, have your miners draw back to the outskirts of the village, where you'd have them (previously) mine out a deep trench and a series of tarp-covered foxholes. When the signal is given for retreat, have your surviving men back in the main area fill the foxholes OUTSIDE of the trench with oil (So as to make them hard to get out of),), as well as slicking up the trench.
Then, have most of your men hold out in the trenches on the other side. Without anywhere to flank, the enemy will be forced into a direct assault (Provided you ensure the trench is RIGHT before the mine entrance).
Once inside of the mines, rocks-fall-everything-dies as necessary, using ventilation shafts as emergency escape routes (That can be mined out with whatever's left of your troops when the battle is won)