small quarry for limestone for roadstone, also maybe site used for converting slag from the nearby furnaces into roadstone and coating the graded bits with tar.
The Thrapston Quarries as you say where at the back of the site and were connected by a MR built standard gauge siding . The pits here were on the edge of workable deposits but the ore was poor I am told and the venture having opened in 1873 was closed in 1881 (wound up 15/06/1883). The working was owned by Thomas Whitehouse of the Thrapston Iron Ore Co Ltd.
The site was sold to the Glendon Iron Co but was worked only for Limestone up to 1900 when it again closed and all plant and railways (gauge unknown but thought to have been Horse drawn) were dismantled. It re-opened again in 1933 for Limestone and a 1ft 11.5in line was laid. Again the quarries proved of little value and after various attempts to work had closed by 1939. The site was abandoned intact complete with Asphalt plant graders and even locos.... the loco were scrapped in the 50s but most of the rest of the stuff survived and much of it can still be seen today as you know. There are limestone faces still to be seen and it is possible Ganister faces but virtually no trace of Ironstone!!!!