Welcome to AN Bob - if the quarries you've got pictures of are already in the site database, then go to the page for it through mines, quarries and sites. Click on either archive album (for old/historic photos) or user album (for recent photos), then click on the link at the top of the page to go to the upload page, put in the file location and some details then upload.
If the quarry you've got photos for definitely isn't in the database (it's worth checking by grid reference as well as name) then you can add it through the tools section of the mines quarries and sites dropdown - once it's been created, add as above!
Follow the horses, Johnny my laddie, follow the horses canny lad-oh!