Miner

The Miner is an illager type mob that spawns underground, presumably looking for some sweet diamonds.

Spawning
Miners replace Spiders and Witches at y=60 and below. They will also spawn in Mineshafts and Strongholds instead of Zombies, and be replaced by Cave Spiders in the Mineshaft and by Prisoner Ghosts in the Stronghold. In all Badlands biome variants Miners spawn ignoring regular height requirements completely replacing the Witches and Spiders in those biomes. You can learn more about the spawning system in "More Mobs" here. You can learn how Spiders and Witches spawn on the official Minecraft Wiki.

Miners have a chance to spawn with a randomly enchanted Iron Pickaxe with a 37.5% chance. The Pickaxe would be enchanted from 8 to 39 levels.

You can also summon a Miner using this command: /function imm:summon/imm/miner. You can obtain a Miner Spawn Frame with this command: /function imm:spawn_frame/imm/miner. Make sure to replace the 'imm' portion with whatever version you're playing on if your version is older than Snapshot 3C (example: Snapshot 2A = imm2a).

General
Miners behave exactly like Vindicators in most situations. Click here to learn more.

Pickaxe switching
If the Miner is within reach of a Diamond Pickaxe (must be lying on the ground) he will pick it up and drop his previous main hand held item on the floor. In that case the tool/weapon he dropped will be fully fixed, unlike upon death. The chances of him dropping the main hand held item upon death are very low, but using this behavior there's a chance to get an incredibly powerful enchanted Iron Pickaxe in exchange for any Diamond Pickaxe, even if it's in the absolute worst condition.

Raids
Since Witches are replaced by Miners if they meet some specific criteria, if those Witches were part of a raid the Miners they brought will join the raid replacing the Witch. As a raid participant the Miner will start behaving accordingly.

Drops
Miners drop the following items:
 * 1-3 Gold/Iron Ore (Ingots if died while on fire)
 * Main hand held item (Iron Pickaxe by default)
 * 4 Torches
 * 5 experience

Data values
Most of data values unique to the Miner are related to technical aspects of the pack, but there are a few notable ones. Still, they share most of their stats with vindicators (which you can check out here). Here's the list:
 * HandItems: [{id:"minecraft:iron_pickaxe",Count:1b},{id:"minecraft:torch",Count:4b}]
 * HandDropChances: [0.085f,0.75f]
 * Tags: iMM, iMMOverworld, iMM_Sound, iMM_Miner
 * Silent: 1b
 * CustomName: §2Miner
 * CustomNameVisible: 0
 * DeathLootTable: imm:entities/imm/miner

Advancements
The Miner can be required (as the Vindicator) for the following advancements (all of which are form vanilla Minecraft): The Miner is also required to be killed for the following "More Mobs" advancements:
 * Adventure
 * Monster Hunter
 * Monsters Hunted
 * Monster Fighter
 * Mob Fighter

Known issues
There are no known issues with this mob in the latest release.