The trail up Hamill Creek is actually the Earl Grey Trail, a 60 km track from Argenta at the north end of Kootenay Lake, up Hamill Creek to Earl Grey Pass and down Toby Creek. You eventually come out in the East Kootenays near the Panorama ski development. This is a real wilderness trail with cable car river crossings, rough trail and the usual expectations of wild animals. The suggested hiking schedule for this trip would be about 5 days.
The trail was named after a former Governor General of Canada who crossed the pass in the early 1900s. Apparently he was looking for a spectacular trip and this is what he was introduced to. It's now completely in the Purcell Wilderness Conservation Area.
Somewhat before the mid-1900s, the lower Hamill Creek valley was the location of some mining exploration. Some equipment remains there still. I understand that this was also an early example of a mining scam, with hopeful investors from NYC funding a several-year project in this area. Their original route into the river valley was right up the lower canyon which is difficult enough that the present trail completely avoids this area, descending to the river from the small settlement of Argenta.
Our trip on Sunday went as far as the second cable car crossing of Hamill Creek. Rain was intermittent most of the afternoon, but quite steady as we drove to the trailhead. Four of our hiking companions were delayed by the rain, apparently enjoying warm soup at a home near the trailhead so we didn't meet them until quite late in the afternoon, on our way back to the parking lot.