Hardy Mine

Hardy Mine was a small operation opened by two brothers about 15 years ago. They were exploring a small canyon, chasing a bright little stream back to its source. As they climbed higher into the canyon, they noticed a cave opening set back to the left from the stream, and decided to investigate.
The cave turned out to be the den for a pair of wildcats that aggressively defended their territory. Both of the brothers were badly injured, but the successfully defeated their attackers. Resting in the shelter of the cave until their wounds fully recovered, they noticed that it had a narrow fissure leading further back into the hillside. Exploring as far back as they could fit into the fissure, they found a cache of diamonds in a leather pouch.
Once they recovered, they returned to town to make a claim on the cave location, and decided to excavate the fissure to look for more treasure. Instead, they found a nice vein of gold. They took on extra laborers and expanded the operation into a proper mine, ultimately with a crew of 18 workers, split into two shifts of nine each. They built up a three story tower across the stream from the mine entrance that they used as their home, and a pair of buildings next to the mine for the workers and their supplies.
There was one small stone building with stables attached for horses and storage. The second building was a longhouse built from fir trees cut from the forested slopes in the area. The long house was 20'x40' with a large central fire pit, and the nubs of a cross hall in the center of the length.
The mine eventually attracted the attention of Granak Smith and his tribe of orcs, who overran the area, killing several of the important miners and terrorizing the others into submission. They took over the tower for their own use, and use it as a sentry tower to guard the mine entrance and to keep the miners from escaping. Many of the 40+ orcs live in the longhouse.
They moved the miners into the mine, keeping them well back from the entrance. They also carved out several small rooms near the entrance to the mine which they use as guard posts and store rooms for weapons and treasure. They keep at least two orcs in each room, with a patrol of another 2 or 3 that make sure the miners stay deeper in the mine away from the exit.
This map shows the entrance to the mine (from the bottom of the image), with the guard rooms and store rooms near the entrance, then the beginnings of the mines and tunnels shown in the upper left. The corridors continue beyond what is shown. This is a starting point for the mine exploration.
Running this scenario depends on how it is started. The players may be grabbed by Granak and his followers, then brought to the mine to get locked inside. Then, they would have to fight their way out (ostensibly stripped of the weapons), or work with the miners to create a new exit location.
They might also be maneuvered into investigating the situation with the purpose of infiltrating and rescuing the miners. I think having them try to sneak in, with interrupted success, is a good way to go. That way, they can deal with the guards and patrols inside the mine openly, but have their escape blocked by the bulk of the tribal forces. This would force them into the mine to rescue the prisoners, and give them a reason to consider other options for getting back out.
The mine itself can stretch to great lengths, and will get further attention in future entries. I think I mentioned 5 levels to the mine, so there are many tunnels and chambers to explore, with varied creepy crawlies taking over in the dark.