Lunch is the second meal of the day. People in Canada typically eat it around noon, or midway through their workday.
Meal times are ingrained in societies and seem logical and natural. However, during the 17th and 18th centuries in Canada a longer and more regimented workday was established. As a consequence, people working further from home pushed dinnertime into the evening, creating a longer period of time between breakfast and dinner. The lunchtime meal came along to fill the gap, and lasts to this day. Canadians typically bring something light and portable to eat at the lunchtime break.
Does the second miner in that photo have a flask? My kind of lunch.