You tune the portal to Cooperstown Mine, and file through. As before, lightning chases around the edges and you're suddenly under the powerful gravity of the planet. You stomp you boots, maybe, fighting the increased weight on your feet. When you have your wits about you, you return to the surface.
At the top of the adit, you find the foreman sleeping with a spear in his hand, while two miners sit on the ground. The sunshines in through a roof hatch, and they're dicing in the small square of light.