CUPERTINO — The city of Cupertino is putting the heat on Lehigh Permanente Quarry to restore part of an illegal back road it expanded last year without permission.

The city wants Lehigh to pay a $100 fine and redo its work on a portion of the 30-foot-wide road running through Cupertino that it widened to haul crushed rock to a neighboring quarry.

If Lehigh doesn’t restore the road and pay retroactive fees, including a $100 fine, the company could face fines of up to $1,000 a day, according to Acting Public Works Director Roger Lee.

“Just like any other property owner in Cupertino, there are rules and codes that must be followed,” Lee said in an email.

Although the county is responsible for regulating the quarry and its mining activities, the city in a May 28 letter told Lehigh it should have asked for city permits before widening the portion of the road within city limits and removing trees to make way for it.

“It’s puzzling to have received this notice since we have been actively engaged with the City to address their concerns, and especially having just filed our application for our reclamation plan,” Erika Guerra, Lehigh’s environmental director, said in an email. “Nevertheless, we will address the allegations and continue our efforts to proactively engage with the regulatory agencies.”

The dispute has arisen while the quarry also is requesting a massive expansion of its mining operation, which would include a new, 60-acre pit. Although mining there began in 1903, residential neighborhoods in recent decades have crept ever closer to the site, resulting in conflict between homeowners and the longstanding quarry.

“We are focused on our recent application to Santa Clara County that would allow us to meet market demand, providing cement and construction aggregate materials used in concrete and asphalt to build homes, buildings, roads, and important public infrastructure throughout the region,” Guerra said, referring to proposed expansion.

Before its expansion, the back road was a 12-foot-wide access road used by PG&E. Lehigh began widening the road without permits last summer so it could transport crushed rock material to neighboring Stevens Creek Quarry. The county discovered the widened road in late June, and after conducting inspections, required Lehigh to stop using it.

Soon after the county closed the back road, the two quarries began transporting the material on city streets, angering Cupertino residents who live along the route.

Leigh trucked the material on Cupertino streets for months before the county put an end to the activity in February.

In an April 29 letter to Lehigh about the company’s use of the road, the county suggested the quarry either restore the road to its original size or provide proof that PG&E needs to use the road at its current size.

Lehigh provides 80 percent of the cement used in Santa Clara County and more than half used in the entire Bay Area, according to the company. Its proposal for a second mining pit would generate an estimated 60 million tons of material.

Contact Thy Vo at 408-200-1055 or tvo@bayareanewsgroup.com.