Patents by Inventor Hilmar A. von Schonfeldt

Hilmar A. von Schonfeldt has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 4265570
    Abstract: A method for controlling a mine roof by drilling one or more boreholes into the roof formation to a location adjacent the top of a mineral seam and hydraulically fracturing the roof formation to enlarge the natural caving zone or to induce orderly caving of a mine roof.
    Type: Grant
    Filed: June 1, 1979
    Date of Patent: May 5, 1981
    Assignee: Conoco, Inc.
    Inventors: Dai S. Choi, Hilmar A. von Schonfeldt