Who would think that one of the most famous mines in the world lies right here in the Highlands of New Jersey, just an hour’s drive from midtown New York City?
The Sterling Hill zinc mine is world-class by any standard, and not just because of what was mined here: history was made here, too, lots of it. So too was much money. Moreover, much mining law was forged here, and over the span of two and one-half centuries, this mine and its twin in nearby Franklin dominated the lives of thousands of New Jersey residents. The economic, social, and scientific significance of our local zinc mines was felt not only in Sussex County, but in all of New Jersey and even far beyond.
Sterling Hill is one of the oldest mines in the United States and was first worked sometime before 1739, more than 265 years ago.
Sterling Hill produced more than 11 million tons of zinc ore. The ore was fabulously rich, averaging more than 20% zinc, and occurred in thick seams that were worked to a depth of more than 2,550 ft below the surface through tunnels totaling more than 35 miles in length.
Sterling Hill is one of the world's premiere mineral localities. Together with the nearby Franklin orebody, 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 have been found nowhere else on Earth. To view the mineral list click here.
The mine is equally famous for its fluorescent minerals. Together with nearby Franklin, almost 90 different mineral species have been documented as fluorescent (view the list here). Specimens from Franklin and Sterling Hill are widely regarded by collectors as the world's finest.
Sterling Hill constitutes a geological enigma — other than nearby Franklin, nothing else quite like it exists on Earth. The scientific literature on these deposits spans two centuries and totals more than 1,000 papers, yet scientists have yet to agree on how they formed.
For more than two centuries the Franklin-Sterling Hill district attracted the attention of the most prominent scientists and naturalists of the day. One of the earliest mineralogical papers in U.S. scientific literature (1810) was devoted to zincite, one of the local ore minerals.
Much U.S. mining law was forged in this area as a result of numerous courtroom battles during the 19th century, when mining was done by numerous small companies that often held conflicting titles to the mineral rights. Resolution of these conflicts established legal precedents that governed much of the mining industry nationwide from 1897 onwards.
The town of Ogdensburg owes its very existence to the Sterling Hill mine. For many decades the mine provided employment to local residents and in many ways dominated their lives. Until the 1980s, most of the tax revenue of the Borough of Ogdensburg was linked either directly or indirectly to the Sterling Hill mine, the only large industrial complex in the Borough.
Without the presence of the Sterling Hill mine, rail service to Ogdensburg would have been much delayed. The establishment of rail service in 1871 brought immediate and long-continuing prosperity to the Borough of Ogdensburg by transporting goods for its local merchants, delivering its mail, shuttling its residents on shopping trips and excursions, carrying its public school graduates to neighboring high schools, and providing a means of shipping the local zinc ore to the smelter in ever-increasing quantities.
The continual need for laborers in the mine brought wave after wave of immigrants to the area, including Russians, Hungarians, Poles, Scandinavians, Cornishmen, Mexicans, Irishmen, and others. Pick up an Ogdensburg phone book and look at the surnames, and you'll see the legacy of those days.
The wealth taken from the hills of Sussex County often had benefits elsewhere. At Princeton University, for example, one of the prime benefactors in the early 20th century was Edgar Palmer, second president of the New Jersey Zinc Company. His name lives on in Princeton in Palmer Square, Palmer Hall, and Palmer Stadium.
Between Sterling Hill and Franklin, so much zinc ore had to be processed that a huge smelting and refining complex was built especially for this purpose in Pennsylvania. Why there? Because of the anthracite coal mines and the Lehigh Canal. The mines furnished the fuel necessary to smelt the ore, and the canal allowed bargeloads of coal to be transported to the smelter at low cost. Thus was born the town of Palmerton. [Think about that — a modern and still-thriving town in Pennsylvania was founded because of zinc mines in New Jersey!]
The historical significance of Sterling Hill is a matter of public record. Sterling Hill was placed on the New Jersey Register of Historic Places in July 1991 (ID #2621) and on the National Register of Historic Places in September 1991 (National Register Reference # 91001365).
Sterling Hill mine was the last operating underground mine in New Jersey. It closed in 1986 after more than 138 years of almost continuous production.
Want to know more? Several fine publications on the history and mineralogy of the Franklin-Sterling Hill area are available; for details and ordering information click here. Two of the most important publications, together with much additional information and photographs, are available on a web site built and maintained by Herb Yeates, a museum associate.
The Sterling Hill orebody contains major amounts of zinc, iron, and manganese, all of which have been commercially produced from the deposit. Many other metals are present as well, but not in minable amounts. Silver and gold, for example, exist only in minute quantities and are saleable only as rare specimens to mineral collectors.
The recorded history of Sterling Hill begins in 1730, when it was owned by the heirs of Anthony Rutgers and was known as the Copper Tract. Visually obvious but sparse showings of bright blue and green copper minerals at the surface led some to assume that Sterling Hill was a copper deposit. Moreover, the abundant zincite (a zinc oxide) in the ore was early mistaken for cuprite (a copper oxide present here in only microscopic amounts), again misleading early observers about the nature of the ore. No copper was ever smelted from Sterling Hill ore.
During the early 1800s the south end of the Sterling Hill deposit was worked for iron ore. The ore there is dominantly franklinite, a zinc-iron oxide of variable composition. Toward the south end of Sterling Hill the franklinite ran unusually high in iron and correspondingly low in zinc, and thus made a good iron ore. The presence of some manganese in the ore was beneficial because it made the iron recovered by smelting much tougher and less brittle.
From 1848 to 1896 two surface pits at Sterling Hill were worked for hemimorphite, a valuable zinc ore mineral. These pits, called the Noble mine and the Passaic mine, remain visible today. The hemimorphite formed during prolonged weathering of the primary zinc ores and formed thick coatings on rock surfaces wherever sufficient open space existed for its formation.
By far the dominant ore minerals at Sterling Hill are franklinite (a zinc-iron oxide), willemite (a zinc silicate), and zincite (zinc oxide). Most of the underground mining of these ores postdates the "Great Consolidation" of 1897, when disparate mining interests at Sterling Hill and Franklin were united under the New Jersey Zinc Company. Prior to that time most mining of these ores was restricted to small open pits and shallow underground workings, but after consolidation the orebody was mined in earnest, ultimately to a depth of more than half a mile below the surface. Sterling Hill production redoubled after closure of the Franklin mine in 1954 and continued almost unabated until the mine closed in 1986. Most of the 11 million tons of zinc ore recovered from Sterling Hill postdates the 1897 consolidation of mining interests.