A mine is designing a comminution plant where an Autogenous mill will be the first grinding unit. The particle size of the feed is at a Dgo of $300$ mm$.$ The desired product size should have a Dgo of $50$ mm$.$ The Bond Work Index of the ore is $18$ kWh$/$t$.$ In the original design, the mill has a diameter of $4$ meters and a length of $6$ meters Due to the electricity restrictions, the maximum power that a mill can use during operation is $1$ MW$.$ Use given answers:

$1.$ If the mine must further reduce its power consumption due to electricity restrictions, what are the $3$ variables that a mine can change if the type of material remains the same?

$2.$ Determine the maximum rate of this mill if its turning power is $110$ kW

If the Bond Work Index of the ore decreased, how will this affect the product's particle size if power input and the rate did not change?

$3.$ If the "intermediate particle size" or "critical size fraction" starts accumulating inside the mill, what are $2$ ways to address it$?$

$4.$ Due to space limitation$,$ the mill can only be $4,3$ meters in length. Calculate the mill diameter if the mill must produce the same rate using the same power as the original mill the ore properties remain the same

Choose from the following answers:

a$.4\mathrm{.}57$ m

b$.59\mathrm{.}07$ t$/$h

c$.$ Rate, feed particle size, product target particle size

d$.$ The product's particle will be finer

e$.$ The product's particle will be coarser

f$.$ Rate, feed particle size, rotation speed

g$.$ Add steel balls or use pebble ports