Which is it? It's the Satellite of DOOM!
In the 1985 audio and book adventure Satellite of Doom Megatron and Soundwave kidnap thousands of humans and force them to bury tons of coal in the desert. Sealing the humans in the cave they set off high temperature explosives that turn the carbon in the coal and humans into a gigantic diamond lens that they plan to launch into space. Bumblebee discovers the Decepticon launching site and Optimus Prime sends Skyfire to take it out, but he fails. Megatron launches the lens into space and uses it to focus the sun's rays and melt the shale in the Rocky Mountains into oil. Optimus again sends Skyfire to stop the lens and Prowl instructs Ratchet to build extra fuel tanks for the Autobot jet's trip to space. Despite his best efforts the diamond is unharmed and Skyfire burns up on reentry of Earth's atmosphere. As the boiling oil threatens to kill millions on the West Coast, the Autobots build a mile long mirror to reflect the lens rays back on it, shattering it. The Autobots launch an assault on Megatron's base, but the Decepticon leader and Soundwave escape in their drilling mole machine.