The Titanic Secret by Clive Cussler & Jack Du Brul

 But upon receiving secret testimony from private detective Isaac Bell, he’s taken back to the year 1911 and a tragedy at Colorado’s Little Angel Mine.
There, Isaac Bell is tasked with explaining the deaths of nine miners. But all is not as it seems and soon Bell finds himself on his way to Europe hunting for clues concerning a rare element of incalculable value.