Longwall mining roof control system
CA 2134518 A1 · Owner: Jennmar Corporation · Inventors: Calandra, Frank Jr.; Stankus, John C.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
In a longwall mining operation a panel to be extracted is, formed in a seam of mine material by longitudinally extending headgate and tailgate entries with the panel beginning in a set up room and ending at a termination line in a recovery room. The recovery room is developed in two stages. In the first stage the recovery room extends, the transverse width of the panel and extends from the termination line a preselected distance to a first sidewall. A roof control system is installed to support the rock strata over the initial width of the recovery room. A primary support system includes mechanical roof bolt assemblies installed in accordance with a preselected bolt pattern. The roof bolt …
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed October 27, 1994. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended October 27, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 27, 2016.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.