Steam engines thirst steam, and the boiler house provides that steam. Our discovery of boiler houses is rather recent, and not all mine sites have them. The more recent mines such as Centennial, Kingston, and Gratiot relied on electric hoists to do all their dirty work. The power to supply these hoists were brought in to the mine from afar – usually in the form of a high voltage line. Mines built before the war were driven by steam, a commodity that those mines had to manufacture themselves. At North Kearsarge – a mine built in the 1880’s – each hoist had its own boiler house. Our first experience with these buildings was at North Kearsarge No. 1, and at first through us for a little loop. Now, however, we knew what to look for.

As at the first shaft, this shaft’s boiler house sat right next door to the hoist building. Its identifying mark was the large six-sided base that once held up a metal smokestack. The smokestack was gone, most likely razed for scrap, but the large opening in its face was filled with a generous amount of white ash. It was connected through a concrete flu to a larger concrete structure. Sitting behind this structure – and connected to it – was another building built from poor rock. Although built from different materials, the two buildings looked to be one and the same.

The concrete part of the building stood about six feet off the ground and was roughly rectangular in shape. It consisted of the concrete flu and a brick lined opening around which sat a two foot thick concrete wall on all sides. Driven completely through this wall was a small diameter pipe, connected to nothing on both ends. Here the pipe is sees protruding from the concrete wall. (the remains of the hoist can be seen behind it)

Inside the concrete walls of this structure was a brick lined opening. The bricks lined all four sides, and were falling in at various points. The opening was about five or six feet deep, and besides the pipe sticking into it from the outside, had nothing else of interest along it.

The foundation of the smokestack had six sides, one of which was connected to the flu while the opposite side had a large gothic opening complete with remains of an iron door. We assumed the door was to provide access to the smokestack to clean it on occasion. Sitting atop the structure were pairs of iron bolts, one on each corner. We think these were probably used to fasten the steel flange at the bottom of the steel smokestack to the concrete base. They appear to have been cut off at their tips.

Boilers required three things to operated. First they needed water, usually supplied by a feed pipe or reservoir. Second they needed fuel, usually coal. In the Copper Country this was originally wood, until reliable supplies of coal could be delivered. The third thing was a path for the hot gases and carbon dioxide to leave the fire boxes. This was accomplished with a flu.

At Kearsarge the smokestack was connected to the boiler house through a large concrete flu. This was basically a tunnel that ran from the smokestack into the main building. Exhaust gases from the boilers would move down this tunnel and up the smokestack. Here is a shot down the flu, from the vantage point of the poor-rock walled part of the building. This part of the concrete flu had collapsed, and here you can see the old rail that once supported the roof. Brick is used to line the flu due to its resistance to high heat. You can see the brick on the right side.

One of the features of our last boiler house was the pair of trenches running the length of the building. These trenches make a comeback here, although not quite as deep as their predecessors. One trench had a series of cross members built from rails (top photo), the other was clear (bottom photo). We’re not sure what these are for, although we think they might have held the fire boxes for the boilers. (the boilers would sit atop these trenches) We have found these trenches in all boiler houses we have found, including the one at the North American. At the first North American boiler house the trench was lined by a series of metal brackets, which might have supported the boilers. If this is the trenches true purpose, it would mean that the boiler houses at North Kearsarge had two boilers in each – one per trench.

Although we had seen a few of these features before, there were a couple that were new to us. The first was this bracket, sticking out of the side of the boiler house’s wall. We only found one (although there could have been more at one time) that went through the wall and out the other side. This one sat right above one of the trenches.

And then there is there. Atop part of the outer walls of the boiler house was these concrete caps. Some had fallen down but it looked as if most of the walls here were capped by them. They could be bottoms of door opening or windows, but they seemed pretty large for that. We would end up seeing them again and again, but on much shorter walls.

For now, we were satisfied that this ruin was indeed the boiler house. But making our job easier was the things we found behind out boiler house – for tomorrow.

next: the trestle