During the years when drafting was done manually, there were roughly 2 drafters for every engineer within the engineering departments. Today, we see this ratio to be about one-to-one. Engineers these days are also using CAD tools to create models and drawings, which they hardly did in the past.
We also see engineering design shifting to lower cost countries as digital communication and global sharing of information is getting easier. Having technical people all around the world allows multiple designers to work during different time zones to accelerate the lead times of the projects. As manufacturing of components shift to cost competitive countries (CCC), having technical people near local shops also facilitate quality control and manufacturing problems resolution.
The percentage of drafters and design engineers unfortunately has not improved over the years (there is much better representation in other departments). While mill suppliers encourage and make targeted efforts to improve hiring of drafters and engineers, very few candidates are interested in these positions. Mining is still perceived as a male dominated industry, and these positions are occasionally required to travel to mine sites.
With the use of computers, the design of grinding mills has come a long way, mostly positive. As mill sizes get limited by manufacturing capabilities, the focus of the design process has shifted from pushing the envelope to creating tools to do it cheaper and faster. Design workforce is becoming more global. With the increased complexity of the tools used, we heavily rely on subject experts.