Your Gold Mine Has Collapsed is a side challenge in Commander's Challenge.
Allied Commander Lydia Winters is collecting soil samples in a region of Chile that is unusually low on ore for her latest experiments. Concerned about the possibility of her finding a way to remove ore, FutureTech sent their Commander to take over the area.
This is the hardest challenge for you to go under the par time as you have to complete it under 4:00 but you have an advantage that you start with 100k credit as your disposal.
EotRS: RS has very high chace to finish this mission as you have very low built time and RS has very high damage infantry. So, ASAP build 4 (or more) dojo and deploy them near enemy base becaution that Lydia have already have a base and she will attack you with high tech toys, but fear not, no bases can stand against 50+ Tankbuster rush. And you have to build a generator to power your base. While training up your army, unpack your MCV and rush it to Lydia's base, it will draw her fire and keep your troop safe, don't worry if it get destroyed. Now after 2:00 has past, you have rush your enemy with every thing you have, this take almost 2:00 left of you but if you quick, you will find a nice gold star.
Soviet: their infrantry is quick to build and have a very powerful secondary arsenal. Don't think, just build a reactor and 4 barrack. Build Conscript, for the first barrack and switch 10 of them to use monotov and the rest use assault rifle. Build Flak trooper for the other 3 barrack and make all ot them use mine. Rush your MCV "IN FRONT OF" your troop so it can crush all the tank and draw enemy fire. Finish of their base and enjoy your victory.
Allied: playing allied means you don't want to past par time but if you want a challenge: Peacekeeper's rush.
The title of this mission is a reference to the Warcraft game series. Where the phrase "Our goldmine has collapsed" is spoken by the advisor once the player's goldmine has been depleted.