If Batman had a subway, it would be in Rockaway

We've visited our share of old mine sites over the past few years. We've also stumbled on some lesser-known aspects of New Jersey's rich railroad history. We've even focused on railroads that overcame major obstacles to create a shorter path from mine to market.

But bats in a mine? Okay, that makes sense. I'm cool with bats and the great work they do in keeping the insect population down. If they're happy hanging out in an old mine, more power to 'em.

Bats in what could be considered New Jersey's first subway? Now we're talking!

Calling the Hibernia hibernaculum a subway might be stretching it a little, but not by much. I first caught wind of the Hibernia Underground Railroad when I was researching another story on Morris County's mining industry. Just on the name alone, one could be distracted into wondering it might have something to do with the abolitionist movement of the 18th and 19th centuries, but this was, literally a railroad that operated underground.

The history of mining in Morris County, of course, dates back to colonial times, with the area's iron-rich hills prompting New Jersey's status as the arsenal of the Revolution. Starting in 1722, a series of independent mines operating off the same rich iron source became known collectively as the Hibernia mines. It appears that there was enough ore for everyone to profit, and that the owners of the mines pretty much worked in harmony.

As technology improved, mining practices evolved, making it a no-brainer for companies to take advantage of steam-driven transportation to shuttle ore from the mine to the smelter and perhaps beyond. Some of the mine owners banded together in 1864 to incorporate the Hibernia Mine Railroad to transport ore from the source to the Morris Canal. We'd found evidence of this railroad in Somerset County, of all places, where its former trestle bridge was relocated first to Hillsborough and now to Raritan, where it's a footbridge in a county park.

Other mine owners at Hibernia took the idea further in 1873, digging an adit (or horizontal tunnel) through the mountainous terrain to connect all of the mines with a railroad. The new Hibernia Underground Railroad shuttled ore from about 300 feet below the peak the mountain itself, with tracks that stretched about a mile from mine to the mouth of the adit. From there, the Mine Railroad took over, making the transfer to the canal or, in later years, farther to other railroads.

By the early 1900s, some of the mines were exhausted, while iron magnate Joseph Wharton consolidated the rest under his own holdings, connecting his own railroad and effectively putting the Hibernia Mine Railroad out of business. The Underground Railroad continued to operate until about 1907, when it lost its connection to the canal. In reality, its years were numbered anyway, as the last ore was mined from Hibernia in 1916.

Disused or abandoned mines tend to be magnets for adventure seekers of all kinds, and Hibernia was no exception. Probably from the moment the mine went belly-up, locals started poking around the adit and mine shafts, eager to search the bowels of the earth or maybe just to get away from naggy parents.

Thing was, though: people weren't the only ones to satisfy their fascination with these holes in the ground. Perhaps due to human disturbance in the caves they'd normally seek out, bats found Hibernia mine, particularly the horizontal path of the railroad, to be irresistible. It's not known exactly when they started staking the tunnel out, but the first report of bat habitation was filed in 1939, with several thousand little brown bats and a smattering of eastern long-eared bats observed. In subsequent decades, researchers observed as many as 20,000 bats, leading many to declare the underground railroad tunnel and the mine as one of the largest bat hibernacula (or hibernation spot) in the nation. A bat enthusiast named John Hall studied the mine and tunnel extensively in the '60s and '70s, banding several and maintaining population counts.

Trouble was, vandals and mischief makers continued to invade the mine, despite landowners' efforts to block the entrance with haphazard barriers. For many years, advocates suggested installing a grate-style gate which would allow bats to travel freely while deterring humans, but to little effect. The land above the mine was slated for development, with large homes and a golf course planned, and the mine was seen as a huge liability. In 1989 the landowner installed an impenetrable foot-thick concrete wall at the mouth of the adit.

The Hibernia Underground Railroad: all aboard for bats,
not so much for humans. Courtesy NJ DEP.

Their usual entry point blocked, the Hibernia bats were essentially buried alive, with just a few very small openings to the outside world. Local human friends of the bats reached out to Bat Conservation International and the New Jersey Division of Fish Game and Wildlife for help, ultimately negotiating with the property owner to create a mine opening sufficient for the bats' easy transit. Through a long and winding process that persisted through successive owners and a few years, advocates finally succeeded in getting the much needed gate installed.

Even after this monumental success, the future for the Hibernia bats is uncertain. The 2010 mine census indicated that, fewer than 2000 bats hibernated there, due to the white-nose syndrome fungus that has decimated the population in several states around the country. Two years later, the wintering bat population was down to 537. Subsequent counts show somewhat of a leveling-off of the decline statewide, so perhaps there's hope that the worst of it is over. Scientists are still working to better understand the fungus, its causes and impact on bat reproduction, with hope that positive human intervention can help.

Here's hoping that the bats' prospects turn around soon. How cool would it be to watch hundreds - thousands - of bats emerging from this old mine train tunnel in the spring?