The unit shall maintain all unpublished information in its files which must be open to the public, except in cases where the investigator still has work in progress on a project leading to a publication or where an industrial firm, interested in possibly locating in the State, asks temporary confidential status for oral and written geologic related information supplied by them or obtained on their properties. In the latter instance the information may be held in confidence by the unit for not more than one year from the date the information was obtained.