Most commonly mitigation measures include systemic archaeological excavation, but all told mitigation measures include:

Both large- and small-scale excavation
Vegetation and soil stripping
Detailed photography
Detailed mapping of sites and features
Archival or Background research (particularly for historic period sites)
Informant interviews (particularly for historic period sites)

Excavations most often occur with a combination of shovel and trowel work. With the exception of the smallest of sites, rarely are archaeological sites excavated in their entirety as the cost would be prohibitively expensive. Most commonly an archaeologist will recommend and the HRMB will require a sample of the site be excavated commensurate with the size of the site, the proportion of the site to be impacted by development, and the significance of the site and materials to be recovered. Excavations can range from just a few square meters up to hundreds or even thousands in the cases of larger and/or more important sites. As with HRIA work, site mitigations require reports presenting detailed information on methodology, stratigraphy, artifacts recovered, additional technical analyses, interpretations and conclusions based on the materials recovered, and of course recommendations for the site in the context of the development and the future.