CCI Archaeological Conservation Workshop

Cliff Cook and the underbelly of a plaster of
paris block lift in chloroplast form

Cliff Cook, from the Canadian Conservation Institute is in St. John's delivering a two day workshop on archaeological conservation field techniques.  The first day was excellent.  We spent the morning in the classroom and the afternoon in the lab practicing block lifts.  Block lifts are used to carefully remove artifacts from a site along with their surrounding soil matrix so that they can be carefully excavated uncovered in controlled conditions in the lab.  It's rare that artifacts will need to be treated this way, so by practicing in the lab we can gain experience with a lot of different techniques that might work in different situations in the field.  We used all sorts of materials to secure the blocks, including plaster of paris, gauze, wax, resin, foam, and dry ice.  We learned a range of techniques for protecting the artifacts and transporting the blocks.  Its an excellent course - a lot like learning first aid for your fragile artifacts.  Big thanks to MUN's Department of Archaeology Conservator, Donna Teasdale, for organizing this event. 

Using dry ice to freeze an artifact and the surrounding soil into a solid block that can then be transported off the site in a solid block.

Dry ice and soil

Using a freeze spray to quickly freeze a small textile fragment

Cellophane is used to keep the artifact from sticking to the block material.  Damp paper towels are used to lock in moisture, and tin foil is used to create a barrier to pour plaster or resin against.

Jason and Miki are planning a block lift using a resin gauze designed for making casts around broken bones.

Assorted blocks.  Different types of blocks will last different lengths of time.  The frozen blocks might thaw out in a few minutes or hours, while the plaster, foam, or resin blocks are stable for months or years.

Photo Credits: Tim Rast