1. Make a danger room with food available via airlock. The danger room is to train the dwarves in whatever weapon you give them.
2. When a useless migrant comes, immediately burrow him into the danger room.
3. Equip weapon, in this case a pick. (you still wrote profit anyway)
4. Danger room train the dwarf to legendary in fighting skills.
5. Once legendary, make a cage trap outside of the danger room airlock.
6. Assign an assload of war/hunting dogs to the miner in question.
7. Murder all of them via spike impalement, drawbridge, or other slaughter of choice.
8. Hope for berserk miner. He will be very unhappy, so three flavors of insanity are possible, as there is a luck factor involved.
9. Once berserk, he should starting breaking his way out of the danger room. This is good.
10. If you've designed the training pit properly, he should be forced to run into the cage trap on his way to cause mayhem and destruction.
11. Now that you have a caged lunatic of murderous intent and capability, transport the cage outside, where goblins will approach it.
12. Hook up the cage to a lever, so that when the Vile Force of Darkness arrives, you can seal your defenses and release the caged demon.
13. UNLEASH THE BEAST.
14. Once carnage is complete, open defenses to lure the survivor(s) into cage or weapon traps.
DWARF BONUS:
Clad the berserker in high quality armor and make the weapon at least exceptional.
MEGADWARF BONUS:
Make his equipment steel, with the weapon itself coated in forgotten beast extract if possible.
ULTRADWARF BONUS:
Candy everything. Except the danger room itself.