In OTL, there were hundreds of thousands of miners by the early 1900s. And lord knows if anyone is willing to get crazy for labour unrest, it's miners. Take a look at the Battle of Blair Mountain, and West Virginia unionizing efforts.
There's a few problems with this idea:
- There weren't "hundreds of thousands" of people, let alone miners, in Alaska until the 1950s and 1960s. Alaska's OTL population in 1900 was just over 63,000, and in TTL, it's likely to be even less, given restrictions on immigration into Russian territory and the fact that few Americans are going to want to trek into Russian territory on the off chance there might be gold there.
- Those population figures get even worse if you consider the fact that of those 63,000, 25,000 were Alaska Native and thus not likely to join in any "revolution" you might have. Alaska's population actually fell between 1910 and 1920 as the easy-to-get ore bodies were mined out, but I'm not sure how much that would happen in an ATL where you have different discovery times and all.
- The type of mining in Alaska in the early 1900s was wholly different from that of the coal mines you're talking about. During that point in Alaska history, it's mostly placer mining, which means miners are spread out over the surface on vast quantities of land. There aren't hundreds of miners on a single mine, except in rare instances.
- By the 1910s, those rare instances have all but dried up. OTL, the deep Treadwell mine was Alaska's biggest in the 1910s, and it was flooded out of existence in 1917 when the ocean poured in. The Kennecott mines are just reaching peak production in 1916-1917, but they're inland and could easily be butterflied away in TTL.