Onshoring Rare Earths Act of 2020 or the ORE Act This bill allows permanent expensing of property used in the extraction of certain critical minerals and metals within the United States and of nonresidential real property used in extracting such minerals and metals. Expensing is the treatment of expenditures as operating costs deductible in full in the current taxable year. The bill allows a new tax deduction for 200% of the cost of purchasing or acquiring such critical minerals and metals extracted from deposits in the United States. The bill requires the Department of Defense (DOD) to establish a pilot project grant program for the development of critical minerals and metals in the United States. A grant awarded under such program may not exceed $10 million. In awarding grants, DOD must give priority to projects determined to be economically viable over the long term and must allot 30% of grants funds to the secondary recovery of critical minerals and metals.