Consult with a lawyer who has experience in leasing minerals other than oil and gas, such as coal leasing. It is likely this will become a very complex legal fight just like the coalbed methane decisions decades before. It will be fought over the nuances of Pennsylvania oil and gas and minerals law. The question is likely to be lithium is a mineral and is its production subject to the terms of a mining lease or an existing oil and gas lease? Even though extraction of various elements from oilfield brines is not unusual, getting a reasonable valuation for lithium in brines derived from the Oriskany sandstone may be difficult at this time. You are at high risk of signing over your rights to a highly valuable commodity for low compensation. I am not a lawyer, so my personal opinion on this may not be terribly useful.