UPDATE 4-Greenpeace blocks 2nd Canada oil sands operation

* Greenpeace blocks conveyors in Suncor mine

* Move aimed at highlighting impact on climate change

* Company expects only minor production impact

* Some protesters arrested away from Suncor site (Adds details on arrests)

By Scott Haggett and Jeffrey Jones

CALGARY, Alberta, Sept 30 (Reuters) - Environmental activists said on Wednesday they canoed into Suncor Energy Inc's (SU.TO: Quote, Profile, Research) Alberta oil sands operation, blocking equipment in a second protest action in as many weeks aimed at disrupting crude production.

Greenpeace said 23 of its activists entered Canada's second-largest oil sands operation, stopping conveyor belts that carry bitumen from the mine to an upgrading plant that processes the tar-like crude into light oil.

The move, part of a long-running campaign against production from what the group refers to as "tar sands", is the second this month. Two weeks ago, protesters chained themselves to equipment at Royal Dutch Shell's (RDSa.L: Quote, Profile, Research) oil sands mine as they sought to highlight what they view as excessive greenhouse gas emissions from the region's oil production operations.

"We came here to send a message and we want to make sure that message is heard," said Jessica Wilson, a spokeswoman for the group, who was among the protesters at the Suncor site. "This is all a push towards (climate talks in) Copenhagen to encourage world leaders to come to a strong climate deal that includes shutting down the tar sands."