Meta_query on custom post

I am trying to use a custom query to retrieve set of events (custom post type) that are happening either today or in the future.

I have a custom field that I’m using (stored as ‘yyyymmddhhmm’ for sorting but the meta_query doesn’t seem to be working. Would anyone be able to tell me where I am going wrong?

$query_args = array(
	'post_type' => 'events',
	'meta_key' => 'start_sort_timestamp',
	'meta_query' => array(
		array(
			'meta_key' => 'start_sort_timestamp',
			'meta_value' => 201203051100,
			'compare' => '>=',
			'type' => 'NUMERIC'
		)
	),
	'orderby' => 'meta_value',
	'order' => 'ASC'
);

$query = new WP_Query( $query_args );