Being a Sudbury boy, I grew up with this lore, so let's see if I can get it right but may stand corrected. The Sudbury mining camp was discovered in 1886 when the Canadian Pacific railway, on its way west, was blasting a rusty rock outcrop just northwest of the current city of Sudbury. When the cut was blasted, the stuff inside was shiney and one of the construction crew, Thomas Frood (aka Frood mine still operating today) knew what it was and staked the ground. Shortly thereafter, a government surveyor, Mr Murray (of Murray mine fame) was running a survey line north from from the Whitefish Lake trading post, no doubt with a mandate of opening up land along the railroad route, when he walked right over top of the Creighton mine. His compass went wacko and in his report he attributed this to the likely presence of a large body of 'trap'. The prospectors then converged on the site and the rest is history; the Creighton mine is still in operation today, down below 7000', with no end to the ore at depth. .......so the answer is....for Sudbury, the railroad came first!

The Mookster