Mining

Overview
Mining is the 1st of 7 methods of progression in the game. Mining can give you stone, ores, jewels and mining xp. There are several tabs at Mining:
 * Mine Pit
 * Equipment
 * Miners
 * Prospectors

Mine Pit
The Mine Pit provides two general types of ore: prospector-searchable and prospector-independent.

Minerals up to and including Bronze will spawn as clusters when you reach a level that is 20 higher than their initial unlock level. E.g. copper ore will only spawn as copper cluster from level 22 and beyond. Clusters have 10 times increased health and yield 8-12 ore and 10 times experience points.

Active Mining
While your pickaxe has energy, you can click on ore in order to mine it. This will reduce the amount of ore remaining in that stack. Upon clearing the entire stack, you will be rewarded 1 of the corresponding ore, which will be added into your inventory. Different pickaxes can be crafted and then equipped. This will change your active mining capability. Higher-tier pickaxes (such as a copper pickaxe instead of a primitive) are typically stronger.

Passive Mining
Some ore can be mined even while your browser is closed. This can be achieved by buying miners. The "passive miner damage" stat on pickaxes and other equipment increases the rate of mining.

Equipment
There are several classes of mining items.

Pickaxes are the most basic mining item and can crafted, thus easy to be obtained. They have an average active and passive mining power.

Idols have a high extra passive damage but a poor active damage, thus they are generally used when player is away from keyboard. Idols can be obtained as loot from tower progress contribution, or from certain rooms in the tower.

Mining hammers, which can be obtain from certain rooms in tower, have a high active damage and maximum charge, but a small passive damage bonus. It is designed for active mining.

In general, at least in low tier (iron or before), using pickaxes have a higher mining efficiency when playing full effort when comparing with idols.In general there are several types of equipment (you can have Active mining equipment and Passive mining equipment equipped at the same time):

Google spreadsheet available to calculate your mining damage per minute can be found here and here.

Miners
Here is the list of costs to hire miners (apart from axes they need to work with). You cannot fire miners once you've hired them.

The formula of increasing "damage per hour" is +36 every tier per each miner from Copper onward (except from eternium to purestone, which increases by +90).

Miners Levels
Miners can be upgraded. Active mining ore of a kind gives XP points to those miners. Passive mining ore and active mining ore give different amount of miners' XP. The amount of XP needed is now in a Calculator for mining exp (Thanks to: weidendorf, hyperzap).
 * Passive mined clusters give ? (some random) xp
 * Active mined clusters give 2 xp
 * Passive mined ordinary ore gives 0.1 xp
 * Manually mined ordinary ore give 1 xp.

Each level up gives +2.5% increase from base damage per hour of a particular miner.

Prospectors
Each prospector increases the likelihood of its specific ore occurring. You unlock prospectors upon reaching a specific mining level and are given one for free. After this, prospectors can be hired for gold and also fired, which can be used if that ore has become redundant. Here is the list to hire prospectors. If you fire prospectors, the gold used to hire them will not be returned.