Mine

Mines out cookie dough and chocolate chips.
Overview
The Mine is the fourth building available in Cookie Clicker Classic, and it represents the game’s early shift from simple manual production into industrial cookie extraction. It costs 2,000 cookies to begin with, and each additional Mine increases the price by 15%. In Classic, each Mine produces 50 cookies every 5 seconds.
Purchasing the first Mine also improves 
In update 2.0, the unlock order was changed so that Mines came before Factories. The stated reason was that players should have raw materials first, before cookies can be mass-produced. That change reflects the Mine’s role as a foundational building in the early game economy.
- Cost progression starts at 2,000 cookies and rises by 15% per purchase.
- Base output in Cookie Clicker Classic is 50 cookies per 5 seconds.
- The first Mine grants +2 cookies per 5 seconds to Grandma output.
- Buying it also changes some Grandmas into miner-themed variants.
Because the Mine sits so early in the building chain, it is often valued for its first-purchase bonus as much as for its direct production. The Grandma boost means the first Mine has an immediate secondary payoff, and that effect remains relevant whenever Grandma production is still a significant part of overall CpS. In Classic-era balance, this helped make the Mine feel like a transitional building: it was not only a source of cookies, but also a sign that the player was moving beyond the basic manual phase of the game.
The building’s visual presentation reinforces that theme. Its appearance is tied to a cookie mine image in the store and a matching in-field depiction in Classic, while some background-related imagery and a Miner Grandma graphic are also associated with it.
For players interested in historical behavior, the Mine is a notable example of how Cookie Clicker’s progression was reorganized between versions. Its position before the 
Official description
Mines out cookie dough and chocolate chips.