Get To Xml Value Inside A Table Column

I need to find a way to query a value stored inside a table column. I have a piece of sample script that looks like this:

select convert(xml,[VALUE]).value('(/ROOT/app/@S_YEAR)[1]','numeric(4,0)') as S_Year from myTble
where [KEY] = 'StringA'

The myTble has 2 columns, Key, Value, and the Value is of data type text. The data stored in there is a large xml node or doc. The table has only three rows for StringA, StringB, and StringC.

I feel bad that I cannot post the xml here because it contains a lot of sensitive data. It will be very hard for me to replace those sensitive data without breaking the syntax integrity.I used to know XPath, but couldn't make out above Select.