Topfmine

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A Topfmine B.
A Topfmine B.

The Topfmines were a series of German circular minimum metal anti-tank blast mines that entered service with the German army towards the end of the Second World War, in 1944.

The mines used a case made of compressed wood-pulp, cardboard and tar along with glass plugs and components designed to be undetectable to Allied mine detectors. Often, the only metallic parts of the mines were the detonator.

To enable the mines to be found by friendly forces the mines were marked with a black, metallic, sandy substance called Tarnsand. Allied forces found that although the mines were undetectable with Allied mine detectors, German mine detectors could find the mines when they had been marked with Tarnsand [1]. The secret of Tarnsand was maintained until after the end of the war, when it was discovered that it was actually Radioactive and the German mine detector incorporated a simple Gieger counter.

Contents

[edit] Topfmine A

The Topfmine A has a rounded case with a raised flat circular pressure plate on the top surface surrounded by a circular shear groove. The case is normally made from pulped wood and cardboard mixed with tar for waterproofing however sometimes the case is made from bituminous coal waste. The SF 1 fuze is inserted into the bottom of the mine and is placed inside a large glass plug which seals the bottom of the mine. A secondary fuze well is provided on the bottom of this plug for installing anti-handling devices. The SF 1 fuze is constructed of glass and wood and and contains a detonator and booster charge.

Pressure of approximately 330 pounds (150 kg) on the pressure plate cause the plate to sheer off from the mine casing, collapsing down on the glass head of the pressure fuze. The glass head is driven downwards crushing two glass vials of chemicals, which react together causing a flash, which initiates the detonator, booster and then the main charge of TNT.

Two versions of the mine were produced - a fully waterproofed version designated To. Mi. A4531 and the normal To. Mi. 4531.

[edit] Topfmine B

The Topfmine B (T.Mi. B4531) is broadly similar to the 'A' version of the mine, the principle difference being the case is smooth with no raise pressure plate. Instead the mine has an internal shear groove to prevent the build-up of water along the sheer groove, which might cause the mine to erode.

[edit] Topfmine C

The Topfmine C (T.Mi. C4531 or Pappmine) changes the design for a more conventional cylinder, with a central glass fuze plug on the top of the mine. The mine is very thin walled and sympathetic detonation of the mine may occur if they are planted closer together than seven feet (2 m).

[edit] Specifications

These specifications are for the Topfmine A, but are typical for the other mines

Topfmine A Topfmine B Topfmine C
Diameter 330 mm 320 mm 340 mm
Height 140 mm
Weight 9.5 kg 10 kg 9 kg
Explosive content 6 kg
Operating pressure 150 kg

[edit] Notes

  1. ^ Specifically the Stuttgart 43 detector (TM 5-223)

[edit] References

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