Patch Hill Quarries, Amherst NH

The Patch Hill Conservation Land is jointly maintained by Amherst & Milford Conservation Commissions. The trails on Patch Hill follow some dirt access roads which once served several granite quarries on the hill. A detailed description of the trail system can be found in the Amherst Walk Book (2010) produce by the Amherst Conservation Commission.

There were four major quarry operations on the hill. Based upon the surviving equipment found at the quarries, the techniques being used split the rock - the quarries can be dated to the 1880’s to 1930’s period. They utilized compressed air drills to drill deep holes for blasting as well as short holes spaced 6 inches apart for splitting with the plug and feather method. The stone was moved and lifted out of the quarries using derricks.

Quarry #1 - This is a pit quarry located a short distance in along the trail on the right. The main feature of interest is a the remains of large a quarry shed. The walls were built out of scrap stone from the quarry itself. The shed would have housed equipment and served as a workshop for the stone cutters shaping the stone to the requirements of the customer. Inside the shed is a T shaped concrete block which once supported an air compressor. The air compressor was sold for scrap metal during WWII. Inside on the opposite side of the shed across from the compressor base is a stone with a square hole cut into it. The purpose of this remains unknown. Between the shed and quarry pit is a granite block with six threaded bolts in it. It may have been the base to a derrick or some type of crane.

Concrete base for an air compressor. The compressor was removed and sold for scrap in WWII.
The wall of the quarry shed is visible in the background.

Stone with a square hole cut into it. Purpose is unknown.

Granite block with six threaded bolts for attaching a derrick or crane.

Quarry #2 - Further up the hill on the left is a pair of quarry pits from another operation (no photos).

View of Quarry #3

Quarry #3 - This is moderate size shallow pit which was being opened up. The quarrymen only cut two to three layers deep into the bedrock before it was abandoned. The surviving stone blocks around this quarry are small in size. The thin layering of the bedrock made it impossible to obtain any large blocks. It limitation most likely caused the abandonment of the operation. This quarry escaped the ravages of the scrap metal dealers. The mast of a derrick is still standing at the site. It has several guywires which attached to nearby trees. The boom of the derrick is missing. This quarry also has an air compressor still in place.

The compressor is an Ingersoll-Sargeant air compressor with vertical lift air discharge valves and a water jacket. The manufacturer changed its name several times making it easy to narrow the date range of manufacture. The Ingersol-Sargeant name was used between 1888 and 1905. The first appearances of this model in the trade literature appeared in the Handbook on Engineering (1902). This unit used a “water jacket” to keep it cool. The water jacket was both on top and on bottom of the cylinder as well as on the ends.  A few feet behind the compressor is a long wide channel in bedrock which may have once supplied water for cooling the unit. Four valves on top of the compressor are missing. They were probably scavenged to repair another compressor. The air inlet is on the bottom of the compressor cylinder. The air outlet is on the top of the cylinder.

Ingersoll-Sargeant air compressor (circa 1902-1905).

View of the piston rod and fly wheels.

Manufacturer identification information

A cross-section view of the unit from “Handbook on Engineering” (1902) with added color coding and labels

Top of the quarry derrick.

Base of the quarry derrick. Iron hardware on the left was where the boom arm of the derrick was attached to it.

One of the quarry derrick guy wires wrapped around a tree.

Quarried Boulder - A short distance past quarry #3 is a quarried boulder in the woods on the left. It was quarried using a step method. The boulder was systematically split into vertical layers and then each layer was subdivided into bars. these bars were removed in a step like fashion. This step method was developed in the 1830’s and used into the mid to late 1800’s. This quarried boulder probably predates the commercial pit quarry operations.

Quarry #4 - This quarry is located on the Milford site of Patch Hill. It is the largest of the four granite quarries. The quality of granite was superior on this part of the hill to that being worked by the other operations. Large blocks of stone could be easily obtained. The quarry was cut into a moderate slope on the hill which drained off all the water without having to resort to pumping.

Some large granite blocks split but never removed from the ledge.

A pair of blast holes.

Amherst Conservation Commission Trail Map with added notation of road names and location of quarries.
(Larger version of trail map)