Design and installation of a rock block monitoring system for the sculpture at Mount Rushmore

An instrumentation system has been installed on Mount Rushmore to monitor any movement of critical rock blocks in the sculpture. These rock blocks were identified through a series of studies dedicated to mapping and structural analyses of the sculpture. While these critical areas of the sculpture are considered the least stable, the sculpture has stood unaltered for nearly 60 years and no major instabilities are evident: Therefore, the monitoring system is primarily precautionary and will operate and collect data for many years to aid in determining any long-term stability issues. The design of the monitoring system incorporated all typical instrumentation concerns while also addressing the unique issues associated with working on this national memorial.