Good morning Dorothy,
I'm Doug, and I'm very sorry to hear of your situation. My goal is to provide you with excellent service today. I have been a CA licensed attorney for more than 3 decades.
The PG&E right of way belongs solely to the utility company and cannot be transfected to, or used, by anyone else---simply because they may want to use it.
Not only are these miners trespassing on your privately owned property, but they are also destroying your property (cutting the fence) in the process---both of these are misdemeanor crimes.
Unfortunately, because your property is located in a national forest, it may be the police employed by the park service who would be the only one's capable of enforcing the criminal laws and prosecuting the miners---in federal court for the violations.
However, if you can identify who is doing this, you can sue the individuals yourself for trespass and destruction of your property and seek not only damages for the harm done but also punitive damages for the intentional destruction of your property.
You may reply back to me using the Reply link and I will be happy to continue to assist you until I am able to address your concerns, to your satisfaction.
I hope that I have been able to fully answer your question. As I am not an employee of JustAnswer, please be so kind as to rate my service to you. That is the only way I am compensated for assisting you. Thank you in advance.
I wish you and yours the best in 2016,