High pulp density fast setting and high early strength backfill method and material
CA 2235526 C · Owner: Li, Shuqin · Inventors: Li, Shuqin; Sun, Henghu; Xu, Weirui
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
This invention discloses a high pulp density fast setting and high early strength, backfill method for underground mining in which novel binding materials, with high early strength properties, are used as the binding reagent where mine tailings, natural, sands, ground sands and industrial waste materials are used as aggregate. The binding material, aggregate and water are mixed together uniformly to produce a high pulp density backfill slurry with 65 - 85% pulp densities. The backfill slurry produced is transported to underground mining stopes through a pipeline by gravity or pumping. Once the backfill slurry fills the stope it quickly solidifies within several hours into a solid backfill …
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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 April 22, 1998 and granted October 5, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 22, 2018.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 22, 2020.
- 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.