Cyprus Natural Analogue Project (CNAP). Phase II final report

Due to the extremely slow kinetics of bentonite reaction in low alkali cement leachates, natural analogues would appear to be the only viable method of studying bentonite reaction. As a result of a review of the available literature, several sites in Cyprus were selected as particularly promising for this purpose. This report presents the results of two short field campaigns in Cyprus in November/December, 2008 and February, 2009. The main aim of these campaigns was to establish if appropriate sites existed for a natural analogue study of bentonite-low alkali cement leachate reaction. Focus is on mineralogical changes and not changes in physical properties (such as porosity and permeability) of bentonite as the industrially-processed bentonite used in a repository will be completely different in terms of its engineering and hydrogeological properties to the unprocessed natural bentonite or analogue smectite-rich materials. The first campaign was in the form of a reconnaissance study to identify sites of likely interest and the second, follow-up, campaign focussed on obtaining preliminary groundwater and solid phase (bentonites/clay-rich sediments/altered igneous rocks/soils) samples which would allow a more detailed assessment of several of the potential sites. A large amount of information was collected during these short field campaigns and subsequent laboratory analysis of the collected samples so, to keep the main report down to a digestible size, much of the supporting information has been collated in seven appendices. These include full details of all 30 sites visited during both campaigns along with sample details, information on the analytical techniques, the analytical raw data and numerous photographs of the sites. The intention is that this report will provide full supporting information for a potential Phase III and a detailed database for our colleagues at the Geological Survey Department (GSD) in Cyprus. Consequently, all the information acquired during this study has been captured so that it might provide a useful resource for any future studies. As with all such initial investigations, several surprises were unearthed, including the overwhelming degree of serpentinisation at some sites. More importantly, however, is that the main aims have been met insofar that: � the groundwater chemistries have been shown to be similar to, and therefore fully relevant to, low alkali cement leachates; � that indications of clay reaction have been identified; � perhaps most importantly, confidence in the site conceptual model has been increased. This has also led to the identification of general areas of Cyprus where bentonite (and analogous clay-rich sediments)/hyperalkaline fluid reaction could probably be studied, and of several specific sites where any future sampling and analysis is likely to be successful.