URL key of a category in Magento

How can I get the URL key of a category in Magento. I have added this text in URL key field -

This is the code which I am trying -

$_categories = Mage::getModel('catalog/category')->getCollection()
->addAttributeToSelect('name')
->addAttributeToSelect('is_active');

<?php foreach($_categories as $_category): ?>
<a href="<?php echo $_category->getCategoryUrl($_category); ?>">
<?php endforeach; ?>

My output is showing like this -

<a href="">
<span>Manual Tile Cutters</span>
</a>

Try this, let me know for the further help.
Mage::getModel('catalog/category')->loadByAttribute('url_key', 'the-key-goes-here');