For the dual-wheel carrying assembly shown in the figure, \( P \) is the load on each wheel, \( a \) is the radius of the contact area of the wheel, \( s \) is the spacing between the wheels, and \( d \) is the clear distance between the wheels. Assuming that the ground is an elastic, homogeneous, and isotropic half space, the ratio of Equivalent Single Wheel Load (ESWL) at depth \( z = \frac{d}{2} \) to the ESWL at depth \( z = 2s \) is \(\underline{\hspace{1cm}}\) (round off to one decimal place).

Reciprocal levelling is performed for points P and Q by placing the same levelling instrument at A and B. The observations of staff readings are tabulated as below. 
If the Reduced Level (RL) of P is 115.246 m, then the true RL of Q, in m, is _______ (rounded off to 3 decimal places)
The information of a mining project for a life of three years is given below:
Additional data: Applicable tax rate = 30%
Discount rate = 10%
Depreciation method: Straight line with zero salvage value
Data from a borehole log with collar elevation at 590 mRL are given below. Composite grade is calculated using cores of 5 m above and below the reference bench at 580 mRL. The composite grade, in %, is: