Shaft sinking is an indispensable yet highly intricate aspect of underground mining, serving critical functions in ventilation, workforce movement, and material transport. In our upcoming analysis, we explore the costs and considerations associated with shaft excavation and construction, offering detailed cost models designed for scoping and pre-feasibility studies. These models are built using data from Costmine Intelligence’s Equipment Cost Calculator and Mining Cost Service, and they reflect industry trends and best practices.
Labor emerges as the most significant cost factor, accounting for an average of 65% of total expenses. Construction materials and equipment operation contribute 20.7% and 7.3%, respectively. Table 3 in the full analysis breaks down these distributions, providing insights into where cost-saving measures can have the most impact. Shaft depth is another key driver of cost. Figure 1 highlights how shallower shafts tend to have higher unit costs due to fixed expenses, such as sub-collar and headframe construction. Meanwhile, deeper shafts face incremental increases in costs associated with hoisting, pumping, and equipment leasing.
Our models incorporate several key assumptions to ensure practical and realistic estimates. A base case shaft depth of 2,500 feet was chosen, with rock quality designation (RQD) values of 60% and uniaxial compressive strength (UCS) values ranging from 10,000 to 36,000 psi. These parameters influence critical aspects like drilling, blasting, and rock support requirements. The models also reflect the growing adoption of permanent headframe and hoist setups, which reduce costs and improve operational efficiency over traditional temporary systems.
In addition to total and unit costs, the upcoming analysis delves into cost distributions by activity and cycle time. For example, shaft excavation constitutes nearly 64% of total project expenses, significantly outweighing other activities like headframe construction or shaft furnishings.
Our analysis also highlights the interplay between geotechnical conditions and cost variability. Factors like UCS and RQD can affect drilling penetration rates, support requirements, and even the number of holes drilled per round. These findings underscore the importance of thorough site investigation and data collection during project planning to mitigate risks and manage costs effectively.
This preview offers just a glimpse of what’s to come in the full article. The upcoming analysis will include detailed cost-per-foot and cost-per-meter estimates, further activity-based breakdowns, and recommendations for navigating the challenges of shaft sinking. Stay tuned for the release, where we’ll provide actionable insights to support your underground mining projects.
