The impact of the wheat economy on Calgary's development was fully apparent by World War 1. As former grazing land was converted to wheat production after the turn of the century, the enlarged rural population enhanced the city's role as a service centre and at the same time, ensured that the industrial base would expand beyond the beef processing industry and become more diversified. The milling trade serves as one of the more obvious examples. The location of the Robin Hood Flour Mill beside the CPR main line stands as further evidence of the railway's absolutely critical place in the development of the city, and indeed, the larger prairie region.
The character of the milling process accounts for the structural similarity of the mills in various prairie centres. The large, multi-storied portion of the milling plant is for grain storage. Mill elevator storage capacity typically provides a two to six-month grain supply. After the grain is cleaned, different wheats are blended to obtain desired qualities. After blending, the wheat kernels go through a series of breakings (grindings) and siftings; as a result, impurities, bran and different grades of flour are drawn off. The flour that is then bleached, enriched and ultimately bagged represents about seventy to seventy-five percent of the mills' production.
Note the grain cars being pushed from the siding. Their design evolved over several decades and their construction was standardized only after the turn of the century. For efficient emptying and cleaning grain cars have smooth-sided interiors and the support structure is on the outside, as can be observed in this photograph from the 1920s.
