The Commission to Inquire into and Report upon Industrial Relations in Canada, often referred to as the 'Mathers Commission' was struck in March 1919 by the Borden Government. It's chair was Thomas Graham Mathers was Chief Justice of Manitoba.
The Commission's mandate was to inquire and report back on the following:
(1) To consider and make suggestions for securing a permanent improvement in the relations between employers and employees.
(2) To recommend means for ensuring that industrial conditions affecting relations between employers and employees shall be reviewed from time to time by those concerned, with a view to improving conditions in the future. (source)
Between April and June 1919 the Commission visited 28 municipalities and heard from 486 witnesses. The Winnipeg dates were May 10 - 13, 1919. The labour side wanted little part in a government inquest and there was not a great deal of representation. The side of industry, however, took advantage of the hearings to air their grievances. (see Conflict in Winnipeg p 107)
Of course the Commission was still in process when the Winnipeg General Strike took place. Its final report was ready and tabled in the House on July 1, 1919.
Their findings included the fact that the 'chief causes of discontentment were: unemployment, the rising cost of living, long working hours, lack of collective bargaining rights, the housing shortage, restrictions on freedom of speech and the press, and unequal educational opportunities'. (source)
The Commission Report (also printed as a supplement to the Labour Gazette, July 1919) is not yet available online.
Photo source and more detailed bio of Mathers:
The Court of Queen's Bench of Manitoba, 1870-1950: a biographical history