10/21/2026
Two men have entered pleas in a significant vandalism and illegal mining case involving the construction of an illegal dirt road along Keystone Creek near Loganville in Sierra County, the Sierra County District Attorney’s Office announced.
District Attorney Sandra Groven stated that her office charged Gregory Arnoldi Jr. and his father, Gregory Arnoldi Sr., with felony vandalism of public land managed by the United States Forest Service and adjacent private property, felony criminal conspiracy, and with misdemeanor charges alleging water pollution, alteration of a stream without first notifying the California Department of Fish and Wildlife, mining without a Reclamation Plan and without a Sierra County Conditional Use Permit, and grading without a permit. Arnoldi Jr. resides in Nevada City and his father resides in Browns Valley.
Both defendants pleaded no contest to felony vandalism of public and private properties as well as to misdemeanor water pollution and stream alteration charges. They were each sentenced to serve 30 days in county jail, to pay a $8,135.00 fine, and to implement a restoration plan for the vandalized public and private properties with all permitting, design, and construction costs borne by them. Both men were placed on felony probation for 3 years, and are forbidden from any form of mining during that period. Should the defendants fail to implement the restoration work by the August 1, 2027 deadline, they will each be sentenced to a further 8 months in county jail and over $30,000 each in additional criminal fines. They are also liable for any restitution to the affected property owners, which will presumably be addressed by their restoration work.
“This was a serious illegal mining case submitted to our office by the California Department of Fish and Wildlife,” Groven said. “While Sierra County is proud of its mining history and heritage that continues to this day, we take the laws that govern mining seriously. In this case, the defendants’ illegal mining scheme vandalized private and public property and caused significant damage to those properties and to the natural resources that make Sierra County a desirable place to live and visit, including damage to mining artifacts. This is not 1849. Accordingly, they were sentenced to jail time for those decisions and will have to restore what they damaged at their expense.”
The case was prosecuted by Deputy District Attorney Matt Carr, who assists in the prosecution of environmental and natural resource crimes in Sierra County and other rural northern California counties through the Circuit Prosecutor Project, a grant program administered by CalEPA and the Placer County District Attorney’s Office. The investigation was conducted by California Department of Fish and Wildlife Warden Dane Frazier, with the assistance from that agency’s Habitat Conservation branch in Rancho Cordova. The District Attorney’s Office commends CDFW for a thorough investigation into this matter.
Anyone with information regarding illegal activities in Sierra County is encouraged to contact the Sierra County Sheriff’s Office at (530) 289-3700. Reports regarding water pollution or poaching should also be made to the California Department of Fish and Wildlife through CalTIP at 1-888-334-CALTIP. Reports to CalTIP may be made anonymously.
