need to get a manhole cover up,, its got what appears to be 4 * 10mm theads were i think bolts would have been ,, but now are missing,,its in a very large wrehouse in a hall way thats used for foot traffic size 600*600 aprox ,,,,, what i need to know is how to lift it is it just a case of screwing in screwed lifting eyes and it can be lifted by two people? or is it more a case of hiring some type of lifting trolly?? it would appear to be lighter weight looking at it ,, as the factery is about 10 years old and the area is vinal covered any one lift these reglary and any problems to be awere of???