Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
CA901794A
Inventor
B. Robinson John
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Joint Coal Board
Original Assignee
Joint Coal Board
Publication date
Application grantedgrantedCritical
Publication of CA901794ApublicationCriticalpatent/CA901794A/en