Archaeological Mitigations

Historical Resources Impact Mitigation (HRIM), or more simply, mitigation, typically refers to the excavation of archaeological sites in the Province. Such mitigation studies may also involve the detailed mapping of sites such as tipi rings or historic buildings, collections of surface artifacts, or detailed historical studies.

If Alberta Culture and Community Spirit requires mitigation excavations as the result of previous Historical Resources Impact Assessment (HRIA) work, they are generally undertaken under a separate permit. Field studies must be completed before the development can proceed. These excavations entail what most people think about when it comes to archaeology: a crew of varying size is mobilized to excavate a site in a timely and efficient manner using hand tools such as shovels and trowels; sediments are most typically screened to collect artifacts, often consisting of stone tools (such as arrowheads and the waste flakes resulting from their production), faunal remains (bones of hunted and processed animals), stones heated to boil water, sherds of pottery, or historic artifacts. Mitigation allows the collection of information that would otherwise be lost if the site was destroyed without study.

Sometimes, depending on the nature and significance of a site, ACCS requires mitigation be undertaken in two excavation stages. The results of the first stage determine the requirements for the second and final stage, and will be communicated to ACCS through either a letter report or an interim report prepared by the consulting archaeologist. This report goes through the review process and a further letter is issued by ACCS setting out the final requirements for the second stage of mitigation.

The results from these excavations require some time to describe and analyse, a process involving detailed technical studies of artifacts, spatial distributions of the excavated materials and oftentimes specialized types of analyses including radiocarbon dating, blood residue analysis or obsidian sourcing studies. Excavations can take one month to complete and another 8 months for the resulting report. The report is often completed sometime after the development project has proceeded. In this case, an interim letter report by the consulting archaeologist will often be prepared and forwarded to ACCS at the close of the field studies advising ACCS that their requirements have been completed and requesting final clearance for the project.

Final Mitigative Excavation Reports will describe the full results of ACCS’s requirements. They will include a complete description, analysis, and interpretation of archaeological materials recovered based on standards established by the ASA. At the conclusion of the reporting process all collected materials are catalogued and submitted to the Royal Alberta Museum, which acts as a repository and permanent curatorial facility. The intent of mitigative reports is to provide professional-level descriptions and interpretations of sites in order to compensate for the loss of these as a result of proposed developments. Mitigative reports range from 20 to over 1000 pages and are a primary source of knowledge for the archaeology of the Province.


An excavated tipi ring near Calgary.
An excavated tipi ring near Calgary
An ancient hearth feature, or fire pit, excavated in Alberta.
An ancient hearth feature, or fire pit, excavated in Alberta.
Laboratory analyses are completed for all artifacts.
Laboratory analyses are completed for all artifacts.


Did you know that...

Through the excavation of Historic period archaeological sites we can gain knowledge about the recent past that people did not often record in writing?