Griffith Silver operates a silver mine in a remote part of a developing nation. The mine was financed by a royalty company, so Griffith Silver must pay $1.50 for each ingot of silver to the royalty company. In addition, Griffith Silver requires $2.50 of labor and $3.25 of materials for each ingot. The local government collects a tax of $20,000 from Griffith Silver each month. Last month, Griffith Silver produced 13,000 ingots of silver. 

What was the fixed cost of producing the 13,000 ingots of silver?