The Seneca Mine began its life during the Copper Country’s adolescence – around 1860. Before then most mines across the peninsula were duds, lit off by excited investors only to fizzle away into nothing. Interest began to fade and new mines were slow in coming. But thanks to the unprecedented success of the Cliff, investors suddenly discovered a new found interest in the region. A new wave of mines began to spring up, a great deal of which set their sites along the rugged bluffs of the Cliff Range – the same formations along which the Cliff had found its own fortunes. One of the largest of these new mines was the Seneca, an endeavor whose namesake was one of the Five Nations – a coalition of native tribes that once dominated the region occupied today by the state of New York.
The Seneca acquired nearly 3000 acres of land stretching over three miles along the Cliff Range. The owned most of the land that sits between the present day town of Ahmeek on the southern end and the Ojibway Mine to the north. Early work concentrated along the Greenstone, which was encased within the rugged bluffs that form the Cliff Range. Like most mines of the day, all hopes were attached to the discovery of a copper-rich fissure vein such as the one found at the Cliff. Towards that end the company focused its efforts along the Cliff Range’s southern most extension – a knobby outcropping or rock sitting alongside what is known today as Seneca Lake.
Subsequent explorations resulted in the discovery of the Seneca Vein – a small and narrow copper fissure that the company hoped would yield results. A small surface plant was hastily erected and a shallow shaft and adit were driven into the newly discovered vein. While work progressed adjacent land was cleared and the humble beginnings of a townsite took shape. The small town was made up of just a few log dwellings, smith shop, stable and agent’s house. A few more buildings were built down at the lake itself and a road cleared towards the mine site. The total workforce at the time was just six men.
Unfortunately the Seneca vein turned out to be a dud, and the company searched elsewhere for their elusive prey. In the following years the company would turn their attention to finding outcroppings of bedded lodes across their property, including the Allouez and Calumet lodes. In 1880 the company set off over 900 acres along its southern property to form the Ahmeek Mine, while work along its northern frontier was halted. It wasn’t until the mine received a new influx of cash – in the form of majority investor C&H – that explorations were continued. This time the company turned to finding the copper rich Kearsarge lode from which its neighbors (the Gratiot and the Mohawk mines) were mining with some success. By 1908 that lode was discovered on the mine’s eastern-most lands and a shaft was quickly sunk to exploit it. Finally it looked as if the Seneca had found its paying lode.
But things would once again turn sour for the company as its Kearsarge shaft began to run out of room to mine the lode profitably. The lode outcropped along only a short section of the company’s land, and the neighboring Gratiot Mine had chocked off most of the lodes upper levels from development by Seneca. There were only two options available to the mine if it were to stay in business. First it could buy out the neighboring Gratiot Mine – freeing up their lodes upper levels and providing much needed breathing room. Or it could attempt to mine the lode at depth, sinking a shaft straight down until it hit the lode and moving on from there (in much the same was as the Tamarack attacked the Calumet conglomerate). Unfortunately both options involved a great investment of capital – an investment that C&H was apparently unwilling to make. The mine was shut down in 1911.
But internal squabbles would result in another turn of events. Unhappy with C&H’s majority stake in the company in lieu of its decisions regarding the mine, a concerned group of investors worked to wrestle control away from the mining giant and regain full control of the company. By 1916 that goal was finally realized and C&H’s stake in the company was bought out by the Seneca Copper Corporation. The mine was re-opened and the newly minted company worked to relieve those space mentioned earlier; by sinking itself a new shaft in 1918. This new vertical shaft – known as the Seneca No.1 – dropped over 1400 feet down to the buried Kearsarge Lode and proceeded to mine it at depth.
Buoyed with a newfound optimism (and some extra cash), the Seneca Copper Corporation turned to buying up its rival to the east – the Gratiot Mine – in 1919. The two shafts of the Gratiot were added to the Seneca’s surface plant and became shafts No.2 and No.3. The company would continue to work these shafts for another half a decade, producing some 3 million pounds of copper before all was said and done.