In the trial, which included wet conditions, the goal was to mine 500 m3 per hour. Among other parameters, cutting performance, turning time and fuel consumption were tracked and compared.
The surface miner features adjustable longitudinal and cross slopes for water drainage. It offers a cutting depths of up to 350 mm and a uniaxial compressive strength of up to 35 MPa. For the trial, it first used a 3.8-m-wide cutting drum, designed specifically for soft-rock mining, and then switched to a 2.2-m-wide drum.
The machine achieved a peak cutting performance of 1,400 m3 per hour. Output also remained high on slopes with a gradient of up to 16%, Wirtgen reported.
When deployed as part of a fleet for a shift, it cut at two depths, 20 cm and 30 cm. It produced significantly smaller and more uniform grain sizes than did the dozer solution, the company reported.
The 220 SMi 3.8 ultimately bested the dozer, and delivered “maximum performance and cost-effectiveness,” the company reported.