Solr Admin Panel assistance required


We are using the Solr Admin panel > Core Admin to run queries on our Omeka instance. We are hoping this will provide us with a way of bulk exporting our collection metadata in XML format. We have had some success, however we are wondering if others are using this same procedure to query their Omeka instance. If so, can you provide, or point us in the direction of, some useful manuals/instructions for search terms and parameters to accurately query Dublin Core (Extended) and system data (eg. URL)?

Any advice would be greatly appreciated.