The miner is the only unit capable of mining gold for the army. Their bags can be upgraded to hold more gold and their pickaxes can be upgraded so they can mine faster. Without them you cannot have units. Miners are very weak and have no way of defending themselves. However they are capable of defense in Stick War : Order Empire
Their major weakness is that they have absolutely no way to defend themselves. They can also only mine at rock formations that are littered around the battlefield. Also, a miner that has just come out of a fort is prey for a Swordwrath, or other units.
In Stick Empires,they made major changes to the miner. His bag now always carries 150 gold,can pray to collect mana,and can attack in self defense. They still have many of the same traits from the original, but these differences make the miner much more powerful. The latest patch reduces the capacity of their bag by a half but increases their speed.
Miners now have 2 abilities to research, the first being 'Miner hustle', which can increase the miner's speed and health, which can potentially kill even a spearton given you have enough miners to outlast that one unit. The second ability is called 'Miner wall', allowing the miner to build a protective wall against the enemy army after being researched, The miner wall is made so that you have enough to even churn out a single unit to wall the enemy forces.
Even with the new attack,the Miner still does very little damage, so he's still open to attack. A miner that has been assigned to mine/ pray with continue unless you tell the miners to attack. They are also able to be killed instantly by Shadowraths that use shinobi I or II.
Fun Fact: The Miner has a Chaos Empire counterpart, known as Enslaved Miners.Edit