Engineered slopes require stabilization to ensure their long-term viability and reduce localized slope failure from erosion and rockfall. The drillers place tensioned steel bar into the rock face increasing the normal force friction and shear resistance along discontinuities and potential failure surfaces. They are applied in a pattern or in a specific block area.
So it requires good access to the rock slope. Visible bolt ends and hex nuts may need to be covered with shotcrete to improve aesthetics (by the way my first dissertation was designing a robotic shotcreting rig) . The hand scaling is the most common and inexpensive form of scaling.
Your options are workers will rappel from the top of the slope , work out of a crane or man lift basket scaling a slope at one time. But have a look at the video its a better method as its safer and can become highly productive for the contractor.