63° Install vs. 90° Install
Standard AMD doors are set 63° off the ribs, over 95% of all door’s AMD manufactures are set to 63°.
The advantage of the door set to 63° is the travel of the door wings are reduced by 27°. This lessens the cylinder stroke by 27° and the door can close 27° faster than a 90° door operating at the same rate of speed.
Some clients have unique situations where they need to use a 90° door frame (where the frame is set 90° off the ribs). Examples would be a portal door or a door that needs to be installed at a crosscut. Another example would be when a mine is installing an AMD door into an existing bulkhead that was originally set-up perpendicular (90°) to the ribs.
Sliding Pedestrian Door
Sliding Pedestrian Doors have become a popular option, over 50% of all doors AMD manufactures include a sliding pedestrian door. The standard size pedestrian door is 30” x 48” yet can be custom designed to wider and taller doors as needed. Pedestrian doors can be set to a 2° or 3° pitch so they are self-closing or at no pitch, requiring the pedestrian to close by hand after use.
Stub Sill Option
The stub sill is an option that has become more popular over the last 5 years. Each “standard” AMD door frame uses channel members around the entire perimeter of the door. The sill is then set into a concrete foundation so the top of the sill is at the same grade as the roadway. To install a “full sill”, the entire width of the door must be excavated to accommodate the foundation.
When using the “stub sill” option, there is no longer a need to excavate the entire width of the door. This is an advantage when a new door is being installed into an existing haulageway where traffic cannot be impeded. The “stub sill” still requires foundations at each end of the doors frame (directly under the vertical frame members). In this case, the center of the roadway does not need excavated. Using stub sills limits the disturbance of traffic flow in these areas where traffic cannot be stopped.
Battery Back-up Door Package/ Battery Operate Door Package
AMD has designed a 100% battery operated door system to accommodate mines that require a door to operate during a power outage. There are multiple packages available to offer solutions to various situations.
Sliding regulators are used in mine doors to allow metered air flow through a door. The sliding regulator is made from the same thickness steel sheet as the door skin. Regulators slide by riding in tracks at both the top and the bottom of the regulator. Once sliding regulator is in desired position, the regulator can be locked in place with a pad lock in 3” increments.
Self-Supporting Door - Outriggers
AMD has designed “self-supporting” mine doors for customers that do not want to utilize a traditional bulkhead design. AMD can design doors with outriggers for multiple needs. Each door is custom designed, and an FEA analysis completed to ensure safety. Please call if you need a Self-Supporting Mine Door!
Welded studs affixed to the door frame improves the integrity between the frame and the bulkhead. Our standard studs (Nelson) are 6” in length and 1/2” in diameter. Studs are welded in a staggered pattern, around the entire perimeter of the frame. The underside of the channel frame is left unpainted for greater adhesion. AMD offers a variety of stud sizes and patterns as per the customer’s request.