The Magma Pump, like other Resource Gatherers, have a lot of HP, meaning that monsters will need a lot of time to destroy it. Unless you need to store resources, it's recommended that you place Magma Pumps along with the other Resource Gatherers around your yard to make an NECoRG (Never Ending Chain of Resource Gatheres) to stall monsters.
This building is the blood of your victories. The Inferno Monsters are known to be powerful, and hard to kill. Make sure you have these buildings highly protected. It is recommended to protect these buildings .