| Gate Fabrication Services
If you are looking for high security and bat friendly closures we can provide design and fabrication services for many types of openings. The Adventure Mine site has enabled us to gain valuable hands-on experience in gate design and methods to resist break-in. Our tour operations demand that we build high security gates that are bat friendly but still allow for thousands of visitors to easily enter and exit the mine. Any gate can be compromised if the perpetrator is determined enough and has the proper equipment, but we can promise to make that task as difficult as possible.
We have a diverse staff with backgrounds in Mining Engineering, Surveying, and other Engineering trades and a wide range of equipment and vehicles to provide superior quality bat friendly closures.
In many cases funding is available and we can build bat friendly closures at little or no cost to the land owner.
This example features double doors for a clear opening width of 7’. This enables equipment access into the mine. Previously this opening had been vandalized numerous times. The last incident involved vandals pulling apart the old gate with a chain and vehicle doing considerable damage to the gate. The newly constructed gate was designed to resist damage by similar methods. Heavy Steel pins insert into steel plates at the top and bottom of the left hand door frame to secure the gate.
The right hand door then covers these pins when closed to prevent access to cutting the pins or attempts to release them from the outside. The bottom pin also inserts into a self-cleaning hole so that accumulations of dirt can’t prevent the pin from properly latching.
Proper Gate Design
Bat friendly gates built by the Adventure Mining Company follow guidelines set forth by Bat Conservation International and others to allow easy bat access. The difficult part is to allow human access when required while keeping unwanted vandals out. Our designs incorporate many features to resist damage.
Common Break-in methods used:
When in college I spent many, many hours exploring abandoned mines both in Michigan and other locations. The friends I had then and myself took pride in our ability to access closed and gated mines while doing no damage to the closures or allowing others in after we had left. Looking back, we did some pretty stupid things, but I learned tricks to defeat gates and now use that experience to design gates to keep people like myself out. We never were purposely destructive, but it was surprisingly easy to temporarily deform the bars on a poorly designed gate or dig under a footing to allow access, and then return the gate to its previous state with no evidence of us having ever been there…
Digging under a gate: We always design a gate to be built into a bedrock footing if possible. If concrete is required, we normally cast a very heavy gauge steel angle iron plate into the concrete footing, along with rebar or other reinforcing. This prevents digging, but also prevents sledge hammering the concrete enough to break it and allow access. The steel plate also becomes the footing for the gate to be welded to, creating a strong, integral unit.
Concrete is poured to make contact with the existing rock to prevent digging around the gate.
Bending or deforming a gate: This involves many possible tools from pry bars to vehicles and chains. We never use less than 3/8” thickness steel in any part of the gate. Heavier gauge is used where it is deemed necessary.
Crossbars are constructed as triangluar tubes for added strength. They are often filled with old fuel hoses to slow cutting with a cut-off saw.
Hydraulic jacks: This is a challenge. A person with a 10 ton portable jack can do a lot of damage. The best defense is to build the doors and other weak points tightly into a frame when locked, and build the entire gate frame tightly into the surrounding rock. Door hinges and lock shackles can’t take multiple tons of force, but if the entire door is designed to contact the frame with very little movement, the force is transferred to the frame and then to the surrounding rock and not the hinges. The door will deform and be possibly damaged, but ideally not enough to allow access or render the door inoperable. We also try to limit areas jacks will fit when building a gate.
Gate is tightly fit into the frame.
Cutting Torches: Stainless steel and other methods such as concrete filled components can be incorporated. Locking mechanisms are the weak point. Even a stainless steel padlock can be heated to the point of failure. We can discuss other options if this is a serious concern. Gates with no access doors are obviously easier to secure, but relatively torch resistant gates with doors can be constructed.
Portable gas powered cut-off saws: These are the biggest threat to gate security we currently know of. This is the tool we use to remove an old gate to be replaced quickly and easily. They are expensive tools ($1000 range), so not all that common in a typical vandals arsenal, but they are very difficult to combat and relatively light and easy to transport. A cut-off saw with a $200 rescue blade can cut concrete, rock, steel, stainless steel, and most anything else. A well designed gate will still take quite a bit of effort to cut through, and fortunately these saws are extremely noisy which is a deterrent. We will always strive to create the most secure gate possible.
 
Hinges are concealed behind the frame of the gate when possible.
Interested in a Bat-Friendly Mine Closure?
Contact us:
Matthew Portfleet
Adventure Mining Company
45540 State Hwy. M-26
Atlantic Mine, MI 49905
1.906.883.3371
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