Mines were laid with the objective of delaying the advance of the enemy, destroying his troops and equipment, impairing morale and disrupting command and communications if the defended area should fall into enemy hands.
Manual of Field Engineering VoII 1936 gives some details of anti-tank mine spacing: two rows, one yard spacing between mines and rows for a road block; two plus rows, two yards between mines and five yards between rows for more extensive gaps e.g. flank protection and belts of 10 rows with 10 yard spacing between mines and rows for an extended minefield.
However, there is little information given in Defence Schemes for Suffolk except for minefield grid references. The war diary for the 10th Cameronians does give the number of mines and rows for each minefield (e.g. one anti-tank minefield at Dunwich had 245 mines in four rows and a mixed anti-personnel and anti-tank minefield at Coneyhill (Minsmere) had 14 anti-tank and 43 anti-personnel in three rows).
Military Training Pamphlet No 40, 1940, gives three methods/spacings for anti-tank mines at 8 and 5 yard spacings:
Above: Left and middle - examples of 8 yard spacing. Right - example of 5 yard spacing
During 1940, 55th Division laid 10,975 Mushroom mines, 1,570 A/Tnk Mine Mk II mines, 5,032 A/Tnk Mk III mines and 1,293 R.E mines.
Anti-tank mines - Military Training Pamphlet No.40, 1940
The R.E No.1 anti-tank mine was issued unfilled with explosive. Hence it could be filled locally by any R.E unit, utilising readily available commercial explosives such as gelignite, ammonal, blasting gelatine or dynamite. It was also designed to be buried one inch below the surface. This meant the firing pressure was very much less than other anti-tank mines. A pressure as low as 40 lbs would fire it (and it would be fired by someone stepping on it). Spacing was to be a minimum of 6 ft to prevent sympathetic detonation.
R.E. No.1 Anti-tank Mine - Field Engineering Pamphlet No.8, 1940
"Mushroom" mine referred to Naval Beach Mine "B", Type "C". These were supplied from Naval Depots filled with 20 lbs Amatol. They were primed with 4 3/4 ozs of Plastic Gelignite wrapped in paper. The recommended laying was in two or three staggered rows so as to provide a frontage with small gaps and the spacing between mines to be at least 20 feet.
For safety purposes minefields were surrounded by a fence with notices every 200 yards (except on the seaward side). All notices were to be removed on ‘action stations’. Control mines would also be laid for occasional test purposes. To conceal the extent of minefields from the air, which were often obvious when freshly laid, dummy lines would be excavated outside the lateral perimeter fence.
For disarming purposes, ‘recovery wires’ were buried which would lead to each mine. The start of recovery wires could be found at marked picket posts. From each picket post would run a main wire with wires then running off at 90˚ leading to the mines.
A soldier form the Essex Regt gives an account of laying mines in the Minsmere Sluice area during August 1942:
"I was attached to the Essex Regiment. We were involved in laying mines from the Minsmere Sluice to where the power station is now. We would dig a round hole and put in it a sort of buscuit tin with a hole in it. Into that you would put the detonator, then gently replace the lid, and very gently cover the mine with sand. We meticulously marked every spot we put a mine on a map, so that they could be lifted later.
Both sides of the belt of mines were protected by wire to prevent people straying into the area accidentally. Sometimes a sheep would get through the wire and would be blown up.
When we were on duty, we would march from Sizewell Hall, where we were billeted, to the Sluice. At the Sluice were the ruins of four cottages, one of which had been a tea house. We used to go into one of them to brew up between laying mines"
Accidental detonations in minefields would seem to have been not an uncommon experience. On Sept 8th 1940, one mushroom exploded killing a workman at Dunwich; on Sept 10 1940, 600 mines exploded at Gunton, with the initial detonation thought to have been caused by a dog, the rest exploding sympathetically. Accidents involving troops occasionally happened as well, for example Cpl Palmer was killed on 25.11.941 while leading a night patrol and becomming lost - he had only been in the locality for three days.
From late 1940 onwards the recommended spacing was in groups of 8 to 10 with 40 yards spacing. This pattern was repeated in depth. If depth was not possible groups were to be laid in clusters with four rows instead of three. This pattern was adopted in order to try and prevent whole minefields exploding sympathetically - i.e. one mine explosion triggering the rest.
After the War, special teams were employed to lift mines, often composed of Italian and German POWs and Polish soldiers who could not go home after the War.
Today, remains of minefields are surely non-existent, so the series of holes at Minsmere Dunes in four rows may be unique as surviving evidence of a WW2 Home Defence minefield. I am unsure if it is a dummy extension or maybe mines detonated accidently and not re-laid or to disarm (this would have to be the case if recovery wires or pickets within a minefield were lost).
Remaining evidence of a
minefield, Minsmere Dunes
Manual of Field Engineering Vol II (All Arms), War Office, 1936
45 Brigade, 55th Div, 10th Cameronian papers, TNA
Military Training Pamphlet, No 40, 1940 - Anti-tank Mines, War Office, 1940
Field Engineering Pamphlet No.8, Anti-tank Mine, R.E. No.1, WO, 1940
Leiston Looks Back 1925-50