By Henry M. Holden
Before becoming the Sterling Hill Mining Museum, it was a zinc mine. The Dutch arrived in the 1600s looking for iron and copper. The value of zinc as a minable commodity didn’t take off until The New Jersey Zinc Company incorporated in the late 1800s. “It took time for mining and science to catch up and discover that there are minerals here that are found nowhere else in the world,” said William Kroth, President Sterling Hill Mining Museum, Inc.
Have you ever seen rocks glowing in the dark or walls changing colors? Inside the mine is a tunnel where you’ll see a wall of dull, brown rocks that begin to glow in vivid greens, oranges, blues, and purples when the ultraviolet lights turn on.
“Come have a fun scientific adventure when you take our underground mine tour,” said Kroth.
“Along the way, you will visit our two museums, go inside the mine itself and see mining equipment, a drilling and blasting demonstration, and the world-famous fluorescent “Rainbow Tunnel” among many other enticing displays. Our tour is sure to engage people of all ages and interests.”
Nestled in the small town of Ogdensburg, New Jersey, the mine which once was one of the world’s richest zinc ore deposits and renowned zinc mine is now a world-famous rock museum.
“Our mine run dump area is perfect for avid mineral collectors,” said Kroth. It is available and is recommended for avid rock collectors 18 and older.
There are two main sections to our mine run dump, the International pile and the Local pile. The International pile contains diverse minerals from all over the world that people can dig through. The Local pile contains hundreds of tons of high-grade zinc ore that was derived from the Sterling Hill Mine itself. Much of the ore in the local pile is full of highly fluorescent minerals. There is a shed on the mine run dump which has a shortwave ultraviolet light in which collectors can check their rocks and see if they do fluoresce.
“Because the mine is a constant 56 degrees year-round, we attract visitors who come to cool down in the summer, and warm up in the winter months,” said Kroth.
Another fun activity is sluice mining. This is a perfect activity for children. Just like panning for gold, children (or mom or dad) can purchase bags of sand that are pre-loaded with gems and minerals or a bag pre-loaded with fossils, or “Motherlode” bag which is a larger mixture of both. The sand mixture is then slowly poured into a tray which is dipped into a water feature to unveil the treasures inside.
Although there are about 35 miles of tunnels, you will be guided through about 1,300 feet of generally level tunnel inside the mine. There are no train rides involved. It is a walking tour, so wear comfortable shoes. It is also wheelchair and stroller accessible.
Along the way, guides will stop at various stations and explain the equipment, history, working conditions, and geology of the mine. Visitors do not need flashlights or headlamps and will see the lamp room, the shaft station, mine galleries dating to the 1830’s, and much more. Although there are 25 levels to the mine, the tour is only for the first level of the mine, visitors do not go down to any lower levels.
“One of the most anticipated exhibits in the mine is the Rainbow Tunnel,” said Kroth. “This is an area of the mine wall where the intensely fluorescent zinc ore is exposed.”
When subjected to shortwave ultraviolet light, the walls fluoresce bright green and red. The red is calcite, and the green is willemite, which was one of the main zinc ore minerals mined here.
“The Rock Discovery Center provides children with a great introduction into geology,” said Kroth. “Guides discuss and educate the children on the three different rock types. Then, the guides focus on six different rocks and how they were formed and why they are important to us today. Each participant receives their own collecting box and after the presentation get to collect the rocks discussed, in a large outdoor area, to take home with them.” Rock Discovery is great add-on to the tour for private groups, especially school groups, scouts, and birthday parties.
Sterling Hill is the treasure chest of minerals. Dubbed the florescent capital of the world, together with the nearby Franklin Mine, 2.5 miles to the north, more than 350 different mineral species have been found here — a world record for such a small area. More than two dozen of these are found nowhere else on Earth.
Almost 90 different mineral species have been documented as fluorescent. Geology.com explains what causes fluorescence in minerals. Quoting from the website:
“All minerals can reflect light. That is what makes them visible to the human eye. Some minerals have an interesting physical property known as “fluorescence.” These minerals can temporarily absorb a small amount of light and an instant later release a small amount of light of a different wavelength. This change in wavelength causes a temporary color change of the mineral in the eye of a human observer.”
The color change of fluorescent minerals is most spectacular when they are illuminated in darkness by ultraviolet light (which is not visible to humans) and they release visible light.
The mine has tours at 10:00 am and 1:00 pm weekends only. Please call 973-209-7212 in advance to make a reservation for the tour. Reservations cannot be done online. Tours are not self-guided; you need to go out with a guide.
Private tours are available for groups of at least 15 paying people. Please call to discuss details, availability, and reservations. Reservations should be made at least 2 weeks in advance for private tours. Please call 973-209-7212 between the hours of 10:00 am and 3:00 pm. For more information on the Sterling Hill Mining Museum, visit www.sterlinghillminingmuseum.org.