You need to take a snowmobile trail into the intersection at the reference coordinates. You can also hike or ATV pass the geocache to Mt. Zircon summit or just get some water at the flowing pipe next to the Mt. Zircon springhouse cache. You can enter from either South Rumford or Milton in addition to the Concord Pond enterence that I have choosen as the parking area for this cache.
The cache has been placed inside of the mine. It is recommended to use the brook entrance to the mine to avoid the vertical shaft. Water drips here even during the dryest times of the year. Bats my be present but none encountered when cache was placed. Highly recommended to bring headlamp or flashlight to fully explore the horizontal mine shaft. Lots of minerals present if you want to paw around and rock hound. Intuition would say to avoid this cache during prolonged wet periods as horizontal shaft may partially flood.
** Be careful and cautious of the unmarked vertical shaft which has a 40 foot drop onto the jagged rocks below. The vertical shaft is overgrown and obscured when foliage is present.