 During Greenfield 's premiership , Alberta 's major non @-@ agricultural industry was coal mining , and the industry was not prospering . Production was more than 50 % greater than demand , and fewer than half of the province 's mines were profitable . The industry as a whole was earning a profit of less than one cent per ton of coal . Miners ' wages had more than doubled ( in nominal terms ) between 1909 and 1920 but had barely held their own against the wartime inflation . In the 1920s mine owners began to roll them back . Besides the low wages , miners were unsatisfied with working conditions in an industry that saw more than 3 @,@ 300 workplace accidents per year . The results had been labour militancy and violence . A general strike in the industry in 1920 had seen strikers assault strikebreakers , throw them off their bicycles , and throw rocks through the windows of buses . Police were used to aid the strikebreakers and had been sometimes attacked as well . One constable was partially paralyzed from the beating he received . Provincial police commissioner W.C. Bryan was warned against inspecting one strike site in a note reading " You spoilt the strike , and if you go ... you will be killed . " He went anyway , and was greeted by an ambush in which three bullets were fired into his car , missing him . 
