diff --git a/f06/src/f06file/extraction.rs b/f06/src/f06file/extraction.rs
index b7cf431..a34e701 100644
--- a/f06/src/f06file/extraction.rs
+++ b/f06/src/f06file/extraction.rs
@@ -312,16 +312,16 @@ impl Extraction {
       .filter(|b| self.block_types.filter_fn(&b.block_type));
     for block in compatible_blocks {
       let mut clone = block.clone();
-      let rows = b.row_indexes.keys()
+      let rows = clone.row_indexes.keys()
         .filter(|ri| self.rows.filter_fn(ri))
         .filter(|ri| self.grid_points.lax_filter(&ri.grid_point_id()))
         .filter(|ri| self.elements.lax_filter(&ri.element_id()));
-      let cols = b.col_indexes.keys()
+      let cols = clone.col_indexes.keys()
         .filter(|ci| self.cols.filter_fn(ci))
         .filter(|ci| self.grid_points.lax_filter(&ci.grid_point_id()))
         .filter(|ci| self.elements.lax_filter(&ci.element_id()))
         .filter(
-          |ci| self.raw_cols.filter_fn(b.col_indexes.get(ci).unwrap())
+          |ci| self.raw_cols.filter_fn(clone.col_indexes.get(ci).unwrap())
         );
       subs.push(clone);
     }