A Mine’s Remains
Copper mining across the Keweenaw shared a uniform approach toward surface infrastructure. Specifically, every mine across the copper country had within it surface plant three main buildings: the shaft house, the rock house, and the hoist building. For contemporary explorers such as us here at copper country explorer, these three buildings become the main ruins we expect to find on any mine excursion. We are rarely disappointed.
Above you will find a diagram (courtesy HAER, Library of Congress) showing an elevation view of the surface plant of the Quincy #2. This also can represent any mine along the copper range, since they all were built in a similar fashion. These three buildings are almost always in line with each other. This fact, along with the type of construction material, size, and shape of the foundation, make for easy identification of these three important buildings in any mine ruin. That’s why we call them the big three.
The Shaft House
Shafts along the Keweenaw was rarely left open to the elements, but instead were often enclosed in a building known as a shaft house. The buildings sole purpose to protect the mine entrance, also known as the shaft collar, from damage and deterioration. Early shaft houses were constructed out of wood, while later buildings consisted of corrugated steel sheathing over a steel frame and supported on a concrete foundation.
Ruins of early shafthouse, because of their wood construction, hardly exist still today. You can find where these buildings once stood by looking for the shaft openings themselves, usually marked by a barb-wired fence surrounding a depression in the ground. More modern structures – like the Gratiot shaft house – can be identified by a long and skinny concrete foundation in line with the rockhouse. The foundation usually contains an earth depression near its center point, marking the capped shaft.
The Rock House
Rock leaving the mine would be brought up an incline to the top of a second building, in which it would undergo processing before moving on. In these buildings, known as rock houses, gravity would be used to drop the rock through machinery designed to remove the excess rock from the copper (poor rock) before sending it to waiting ore cars at it’s base. Early rock houses often were served numerous shafts at once, and were in turn built in a central area. Later, these rock houses would paired with specific shafts, and were built closer and closer to the shaft houses until the two because almost one building. (Which it did in some cases)
Early rock houses can be identified by large and flat concrete or rock foundations, upon which stand various pedestals on which crushing machinery once operated. For more modern structures, such as at the Gratiot Mine, the tell tale sign will be a large concrete structure straddling an old rail line. This structure may have a “cap” consisting of a concrete slab punctured with holes (to drop the copper rock through) or have nothing on top.
Hoist Buildings
These buildings housed the large steam engines used to raise or lower material in and out of the mine. The engines were used to turn large drums or wheels upon which long lengths of steel cable were wound. This cable would exit the building through a wooden “sleeve” on one wall, over a series of cable carries, and up over a large wheel in the shaft house or shaft-rockhouse combination. From there the cable would move down the shaft along a underground rail line (called the skip road) along which material would be moved in and out of the mine.
These rather large buildings are very easily identifiable, even in early mines. Ruins of these buildings always consist of a outer wall surrounding a rather large inner foundation. This inner foundation is thick, and peppered with a number of steel rods sticking out of its surface. Its most noticeable feature is a large hallow in the ground and foundation in which a large drum or wheel would spin freely. ( See “Anatomy of a Hoist” for a detailed look. )