Patent Number: 
Section: claims

1. A drillhole plug system, comprising:a frame or housing that comprises a corrosion-resistant material and is sized to fit within a milled portion of a directional drillhole that comprises a hazardous waste repository; anda material that is positioned in at least a portion of the frame or housing and exhibits a creep property such that the material is configured to fill one or more voids between the frame or housing and a subterranean formation adjacent the milled portion of the directional drillhole, the material comprising a natural material that comprises a rock material. 2. The drillhole plug system of claim 1, wherein the rock material comprises at least one of shale, clay, or salt. 3. The drillhole plug system of claim 1, wherein the rock material is the same or substantially the same as the subterranean formation. 4. The drillhole plug system of claim 1, wherein an outer diameter of the frame or housing is greater than a diameter of the directional drillhole. 5. The drillhole plug system of claim 4, wherein the frame or housing comprises a first frame or housing, and the material comprises a first material, the system further comprising:a second frame or housing that comprises the corrosion-resistant material and is sized to fit within another milled portion of the directional drillhole that comprises the hazardous waste repository; anda second material that is positioned in at least a portion of the second frame or housing and exhibits the creep property such that the second material is configured to fill one or more voids between the second frame or housing and another subterranean formation adjacent the another milled portion of the directional drillhole. 6. The drillhole plug system of claim 5, wherein the subterranean formation comprises a first rock formation, and the another subterranean formation comprises a second rock formation different than the first rock formation, and the first material substantially matches the first rock formation and the second material substantially matches the second rock formation, andthe first frame or housing comprises a first drillhole dimension, and the second frame or housing comprises a second drillhole dimension different that the first drillhole dimension. 7. The drillhole plug system of claim 1, wherein the frame or housing comprises a first frame or housing, and the material comprises a first material, the system further comprising:a second frame or housing that comprises the corrosion-resistant material and is sized to fit within another milled portion of the directional drillhole that comprises the hazardous waste repository; anda second material that is positioned in at least a portion of the second frame or housing and exhibits the creep property such that the second material is configured to fill one or more voids between the second frame or housing and another subterranean formation adjacent the another milled portion of the directional drillhole. 8. The drillhole plug system of claim 7, wherein the first and second materials are the same or similar rock material. 9. The drillhole plug system of claim 7, wherein the subterranean formation comprises a first rock formation, and the another subterranean formation comprises a second rock formation different than the first rock formation, and the first material substantially matches the first rock formation and the second material substantially matches the second rock formation. 10. The drillhole plug system of claim 7, wherein the first frame or housing comprises a first drillhole dimension, and the second frame or housing comprises a second drillhole dimension different that the first drillhole dimension. 11. A method for sealing a drillhole, comprising:milling a portion of a directional drillhole that comprises a hazardous waste repository;inserting a drillhole plug into the milled portion, the drillhole plug comprising a frame or housing that comprises a corrosion-resistant material and a material that fills at least a portion of the frame or housing and exhibits a creep property; andsealing the directional drillhole with the material of the drillhole plug that fills, based on the creep property, one or more voids between the frame or housing and a subterranean formation adjacent the milled portion of the directional drillhole. 12. The method of claim 11, wherein the milled portion is located at a vertical portion of the directional drillhole. 13. The method of claim 11, wherein the milled portion does not include casing and other portions of the directional drillhole comprise casing. 14. The method of claim 11, wherein the material comprises a natural material. 15. The method of claim 14, wherein the natural material comprises a rock material. 16. The method of claim 15, wherein the rock material comprises at least one of shale, clay, or salt. 17. The method of claim 15, wherein the rock material is the same or substantially the same as the subterranean formation. 18. The method of claim 15, wherein an outer diameter of the drillhole plug is greater than an outer diameter of the directional drillhole. 19. The method of claim 11, wherein the drillhole plug comprises a first drillhole plug, the frame or housing comprises a first frame or housing, and the material comprises a first material, the method further comprising:milling another portion of the directional drillhole that comprises the hazardous waste repository;inserting a second drillhole plug into the another milled portion, the second drillhole plug comprising a second frame or housing that comprises a corrosion-resistant material and a second material that fills at least a portion of the second frame or housing and exhibits the creep property; andsealing, based on the creep property, the directional drillhole with the second material of the second drillhole plug that fills one or more voids between the second frame or housing and another subterranean formation adjacent the another milled portion of the directional drillhole. 20. The method of claim 19, wherein the milled portion of the directional drillhole is located in a vertical portion of the directional drillhole, and the another milled portion of the directional drillhole is located in a curved or horizontal portion of the directional drillhole. 21. The method of claim 19, wherein the subterranean formation comprises a first rock formation, and the another subterranean formation comprises a second rock formation different than the first rock formation, and the first material substantially matches the first rock formation and the second material substantially matches the second rock formation. 22. The method of claim 19, wherein the subterranean formation and the another subterranean formation are the same subterranean formation.