what is the eldorado exploring expedition, who is the leader and what is mallows opinion of the men in the expedition?

This exploration looked for the mythical place of gold Where people could get rich quickly. Like in Africa but without the gold!

"This devoted band called itself the Eldorado Exploring Expedition, and I believe they were sworn to secrecy. Their talk, however, was the talk of sordid buccaneers: it was reckless without hardihood, greedy without audacity, and cruel without courage; there was not an atom of foresight or of serious intention in the whole batch of them, and they did not seem aware these things are wanted for the work of the world."

The Eldorado Exploring Expedition, is led by the station manager's Uncle. Mallow is suspicious of their intentions and believes they have something to do with the delay in the arrival of the rivets he needs for the boat.