They were in the middle of nowhere and many men wanted to get out of there but they were pretty much forced to continue the work. Even knowing the problem, some men still joined the workers to replace those killed because they needed the money.
They built large fires at night and put up thorn fences but the lions kept coming. By this point they had named them "Ghost," and "Darkness." The men were becoming sleep deprived. They eventually brought in a hunter who eventually tracked them down and killed them. They were massive beast with both measuring around ten feet in length.
Although the exact number hasn't been confirmed, many reports state that in nine months, the lions killed 75 men.