First of all, for the question of how did the dungeons get there or how we found them let's say that they have been hidden since ancient times by a race of magical wizards. They cast spells making the entrances impossible to find by normal humans, but the last great wizard died (along with the last knowledge of how to use magic) a few days ago for unknown reasons and so the spell was lifted. Videos of people discovering the entrances to these magical dungeons spread across the internet like a plague, and with some lucky enough to find the mystical loot at the end of the dungeon, causing a global interest in exploring these areas.

Let's say for simplicities sake that the artefacts recovered do not have any magical ability or use other than being worth a large sum of money. Plenty of people and companies want to get a part of this new industry; the industry of dungeon exploration, and are willing to do whatever it takes to be as efficient as possible.

To my actual question. What would be the best way for our society to explore dungeons with our level of technology? When I say our level of technology I think technology that could surface in the next 10 years would also be acceptable as this new discovery would cause a surge in technological advancements as people try to make the most money.

I will now list some dimensions and numbers relating to the dungeons but these are only of the top of my head so please feel free to change them in your response if you have any better ideas:

• The dungeons would be a fairly typical cave-like design with tight space hallways and open rooms. Another point I should say is that there maybe be monsters lurking in the dungeons but that is for you to decide. If you want to tackle this question role play style, with a crew of dungeon explorers who are famous for their use of insert technology here to slay their way to the jackpot, be my guest and include monsters. But If you want to just go by a logical stand point and only care about efficiency of actually getting the loot out, please ignore the monsters. But if you do decide on monsters, feel free to use whatever ones you want as long as they would fit into an underground dungeon that hasn't crumbled in possibly thousands of years.
• The dungeons would be a couple 100m deep at most and cover an area of approximately 2 square kilometres. If humans couldn't find it then why have an intricate dungeon layout you ask? Lets say these wizards were a suspicious bunch and wanted to protect their stuff from people and other magical wizards alike so they built elaborate dungeons that required different kinds of magic to open rooms ensuring other wizards would not be able to access the loot. But what they didn't account for is our current technology as they stopped updating their defences centuries ago, and now with our electric machinery, the door are easy to drill, cut or even shoot through.
• The layout of these dungeons can difference from each other so you can't necessarily drill straight down and find some every time. Unless this is a viable technique in some regard?
• There would be about one per square km, so enough that investing in exploration technology will not be a waste of time. The industry would boom for years.
• Also loot rooms would be scattered around the dungeons by the wizards, so a robber might stumble across one and then leave not taking all the treasure, so the whole dungeon would have to be explored to be sure all the goods have been found.
• The entrances would be meters wide, so possibly seen by satellites but would still be hard to locate or be sure it is even an entrance.

Now some ideas I had. Feel free to ruin or improve on them.

• Large mining companies could set up mining machinery and simply drill through the whole dungeon but I'm not sure how they could ensure the artefacts are not damaged.
• Slave labour camps might be established in poorer countries to mine them out by hand.
• Specialised military teams might tackle the dungeons on foot with guns, torches and ram down the doors.
• Treasure hunting groups might form with legendary yet mysterious teams of bandits looting dungeon to dungeon without a trace.

A mix of both industry and individual exploration answers would be great. As in business vs individual people exploring the dungeons themselves. I imagine that conflict in this world might arise from the large companies farming these dungeons with no care for the environment or even for their workers. And so small villages situated next to a dungeon might want to keep it for themselves or even protect these dungeons from the large companies or even worship them. I'm very curious to see what other people's ideas about a world with dungeons are so please share!

The artefacts don't have a set worth let's just say that any means necessary would still turn up a profit as I don't want to exclude any ideas. If any further information is required just let me know and I'll add it. Likewise if anything is unclear I can change that too.