The tweet below was on Sohi's twitter at 8:11 Am today.
Judging by the background when looking at a previous event at the Vale Cavern(Cancer event), it's clear today's Cleantech announcement was made at the Vale Cavern. Notice the red flamey background.
But when you look at the tweet, Sohi did a speech, Sohi did the photo op and then answered questions all by 8:11am today.
This tells me the 10:15 am meeting/announcement was for something else OR it was cancelled/postponed for some reason.
https://pbs.twimg.com/media/Dqw-pYUUcAIEnyX.jpg
Improving energy efficiency in mines is critical. Today I announced the launch of the $10 million #CrushIt challenge for innovators to develop new technologies to cut energy consumption while crushing mined rock. Time to Crush It!
8:11 AM - 30 Oct 2018
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Miners for Cancer Christmas Gala

Date: Friday, December 7, 2018
Venue: Science North Vale Cavern