WRT stopping power of the .45 Long Colt cartridge, there are some variables that must be taken into account. The .45 Colt was introduced in 1872 and in 1873 was adopted as the official U.S. Army handgun round together with the Colt Single Action Army revolver. This was a black powder cartridge designed for use in weapons with much milder steel than is available today. The ballistics from a hand gun were roughly 850 to 900 feet per second with a 230 to 250 grain lead bullet, comparable to the .45 ACP (Automatic Colt Pistol) round originally designed for the venerable Colt 1911 pistol. A good man stopper but, especially with the soft lead bullets used at the time, limited in penetration on larger animals.
Even when smokeless powders became standard around the turn of the last century, factory loads continued to be loaded so as not to exceed the pressures generated by black powder loads, as they are to this day. There are two particular reasons for this. First, the cartridge cases for the round were much weaker than those designed for more modern handgun rounds, using what is known as a "balloon head" design. In this type of case, the case head is relatively thin with the primer pocket extending beyond the head into the case interior leading to the case head separating from the case body if too heavy a powder load is used, with dangerous results. Even though modern .45 cases are made with a thick case head equivalent to other modern cases, there are still many older Colt revolvers and reproductions in use that aren't designed for "magnum" pressure loads. Even currently manufactured versions still have thin cylinder walls that preclude the use of overly robust loads. It is quite possible to safely fire .45 Long Colt rounds loaded to .44 Magnum like ballistics, but only in revolvers such as the Ruger Blackhawk or Freedom Arms which are much more heavily built.
The chambering of rifles for the .45 Long Colt cartridge is a fairly modern development driven by such things as Cowboy Action Shooting competition. While it was common for early lever rifles such as the 1873 Winchester to be chambered in pistol calibers so that a person could use the same round in long gun and sidearm, those were rounds such as the .44-40. Other than some kind of custom conversion (unlikely to be owned or carried by the miners) there would not have been a rifle chambered for the .45 LC at the time of the Ape Canyon incident.