A sinkhole, about as deep and wide as a four-story building on a busy stretch of Interstate 80 in Wharton, was caused by the collapse of an abandoned mine shaft, forcing workers to endure major repairs and delays of more than an hour, according to reports. officials.
The large depression in the shoulder of the roadway, which is 40 feet deep and 40 feet wide, has closed the eastbound lanes, forcing motorists to drive to Exit 34 or take alternate routes, requiring a reopening of the roadway is still unknown.
A specific time when the two-lane highway will reopen is “too early to estimate” due to extensive repairs, according to a Friday update from the New Jersey Department of Transportation. With freezing rain expected to blanket the area Friday evening into Saturday morning, weather could also play a role, officials said.
NJDOT crews worked “around the clock” to complete the repairs, officials said, with the area stabilized and excavation work beginning Thursday evening.
Steve Schapiro, a spokesperson for the NJDOT, told NorthJersey.com that once excavated, they will fill the area with mesh and rock aggregate, concrete and other fill before repaving the roadway.
It was not clear whether the area where the sinkhole occurred had been previously monitored or if there was cause for concern. Schapiro did not respond to that request.
Around 12:30 p.m., delays ranging from 55 minutes to more than an hour were reported at the Wharton exit and at Exit 28, an alternate exit for motorists to eastbound Route 46, according to alerts from 511nj.org.
The sinkhole was first reported by officials around 7:45 a.m. Thursday, with photos from motorists posted on social media showing a highway packed with traffic as New Jersey State Police worked to divert vehicles from the highway .
Morris County has hundreds of abandoned mines
Morris County is filled with more than 100 abandoned underground mines, most located in the northwestern half of the county, with ore consisting mainly of magnetite, mica and graphite, according to a 2020 Morris County geographic report.
New Jersey is prone to the effects of sinkholes and subsidence, or the sinking of the land, especially in the northern region of the state, partly due to its abandoned mines, the report said.
The Garden State was traditionally an iron-producing state, with the first mines drilled in the early 1700s. Although mines in the state have closed – the last closed in 1986 – continued development in the northern part of the state has been “problematic” due to previous extensive mining, which caused subsidence, the report said.
The report states that one problem is that many of the mines’ surface openings have been “improperly filled”, with roads and structures built on top of the sites.
The several mines in Rockaway, Wharton and the aptly named Mine Hill area include the Mount Pleasant Mine, which shows a location between the rear of the Avalon apartment complex on North Main Street and Route 80 eastbound, where the sinkhole appeared .
The Mount Pleasant Mine is one of the oldest in the state, first opening in 1786, according to the nearly 600-page geographic study “Iron Mines and Mining in New Jersey,” compiled in 1910 by William Bayley, and often cited by the New Jersey. Ministry of Environmental Protection. The mine was operated steadily until 1896, when it closed. At the time of its closure it had a length of 3,500 feet and a depth of 1,400 feet as measured on the slope.
Through June 1880, the mine produced an estimated 336,000 tons of ore, Bayley wrote.
Email: lcomstock@njherald.com; Twitter: @LoriComstockNJH or on Facebook.
This article originally appeared on NorthJersey.com: Route 80 sinkhole in Morris County caused by abandoned mine shaft
