Written by Samantha Kummerer, WTVD ABC News

RALEIGH (WTVD) -- The William B. Umstead State Park attracts more than a million visitors a year. The wooded trails winding near creeks offer a haven for many in the heart of Wake County.

Former Wake County commissioner Ervin Portman is one of the many who enjoys the escape the park offers. In recent years, Portman's passion for the park has sent him on a mission to save it.

"We need to be as good as good as stewards, as people that came before us were because this park is supposed to be enjoyed for generations to come," Portman said. "If we continue to allow one encroachment after another encroachment after another encroachment, we're going to lose what we're trying to save."

The company Wake Stone has operated a rock quarry next to the Wake County state park for decades. It was a controversial issue back in the 1980s but Wake Stone was eventually granted a permit to mine on the land under certain restrictions. One of those stipulations included a 50-year sunset clause.

However, Portman said a recent change to the mining permit could mean mining could last much longer.

The issue Portman pointed to stems from a single word.

The initial permit issued back in 1981 said: "If all quarryable stone is not removed, the right of the State to acquire the quarry site shall accrue at the end of 50 years from the date quarrying commences or 10 years after quarrying operation have ceased without having been resumed, whichever is soon."

The word sooner was included in every permit renewal until 2018 when suddenly it changed to later.

A small change but one that essentially means mining doesn't have to stop after 50 years if Wake Stone isn't ready to end quarrying.

Emails published publicly online show Wake Stone requested this word change back in 2011 and again in 2018. While the change didn't stick in 2011, it did in 2018.

A published memo on DEQ's website states the change was approved to match the wording in the Mining Commission's 1980 decision. While the decision did say later, Portman said it was not a final decision and the 1981 official permit and all permits renewed after said 'sooner'.

"When I read them say that it was a typographical error. And they had just discovered it after 30 years. That didn't sit right with me," Portman said.

"Why would you accept the permit with an error in it, and not say anything?

Why would you accept it eight times, and not say anything over 30 years?"

The I-Team reached out to both DEQ and Wake Stone. Nether answered questions about the change or offered any comment.

Rufus Edmisten was North Carolina's Attorney General when the initial permitting was being considered. While he didn't directly work on the permit, he was involved with matters of the state and remembers how controversial the issue was.

He said he believes the permit would not have been approved if the 50-year sunset clause was not included.

"With faded memories with people being deceased, I don't know how that happened but I know this, that for sure, we all thought that the quarry was supposed to last for 50 years and 50 years only," Edmisten said. "We wouldn't have negotiated the contract had it not been a 50-year deal. Wake Stone knew that as far as I understand."

Currently, DEQ is considering Wake Stone's approval for a 2nd quarry on the Old Fellow Property.

The Raleigh-Durham Airport Authority Board of Directors already approved the expansion. The quarry would generate around $24 million for the RDU airport who owns the land.

Portman said he is not against mining but believes it needs to be done in a way that doesn't impact protected parks.

"It's not their land. It's our land. That's the impact. That's what we're fighting for them to investigate," Portman said.

Portman and other advocates have asked DEQ to reconsider the permit change, so far none has been announced.

"I would hope that we will sooner than later, solve this in favor of a 50-year limitation," Edmisten said.

Read the article on WTVD ABC News