Size Reduction and Milling

Bond's Work Index $W_i$ is defined as the gross energy (in $\text{kWh/tonne}$) required to reduce a material from:

Options:

• (A) Theoretically infinite feed size to $80\%$ passing through a $100\text{ \mu m}$ sieve
• (B) $1\text{ cm}$ to $1\text{ mm}$
• (C) $10\text{ mm}$ to zero
• (D) $1\text{ m}$ to $1\text{ cm}$