diff --git a/private/lib/PipelineHelper.php b/private/lib/PipelineHelper.php
index d15f05d..64a2467 100644
--- a/private/lib/PipelineHelper.php
+++ b/private/lib/PipelineHelper.php
@@ -71,7 +71,11 @@ class PipelineHelper {
 		$rval = array(
 				array(
 					'$project'=>array(
-						'date'=>array('$add'=>60*60*1000)
+						'date'=>array(
+							'$add'=>array(
+								array('$date',60*60*1000)
+							)
+						)
 					)
 				),
 				array(