If I thought that getting historical background to Cordon Sanitaire defoliation efforts (see previous post) was challenging, I was wrong!

Trying to find anyone who has in-depth information on the electronic early warning systems installed on the fences was an even more daunting task. To be very honest I am not in any way convinced that what I have managed to find holds too much water and this is once again where I will be hoping that someone, somewhere reads this post, tells me I have written complete rubbish and puts things right. I can take it and no offence will be taken I assure you. We simply need to get this as factual as we can. There has to be Rhodesian Army veterans that actually installed and monitored the electronic side of things that can help here.

The following redaction comes from more than one source, the reliability of which has not been confirmed to me. From an intelligence source and reliability perspective I therefore have no option but to rate it as F/6 (Insufficient information to evaluate reliability. May or may not be reliable/The validity of the information cannot be determined) and should therefore by no means be quoted as being the way things actually were. Read on………..

For the sake of simplicity we will consider the Cordon to be 25 metres wide, fenced on both sides, and containing anti-personnel blast mines.

On the home side a system of electronic sensors divided into monitored sectors and wired to sector control boxes formed the basis of the early warning system. I have not been able to find any information as to what type of sensors (movement, vibration, broken electrical circuit, audio, etc.) were used, nor who was responsible for installing them (possibly the Rhodesian Corps of Signals (8 Signal Squadron)).  According to one source these control boxes were placed in bunkers close to the home side fence and manned full-time by troops waiting for an alarm to be set off.

Logic makes me think that a combination of activation triggers may have been used. Apparently the idea was that any penetration of the Cordon would be detected by detonations or some form of electronic sensor. My information claims that reaction to these events was primarily by vehicle and took place within 10 minutes of a signal being received. In addition to the vehicular response, artillery fire was also used to put down fire on ranged, pre-selected targets. I imagine this would be from 25 pounder howitzers or possibly 120mm mortars.

It is my understanding that the only parts of Cordon Sanitaire to be fitted with an electronic early warning system were the Musengezi/Mukumbura, and Nyamapanda to Ruenya minefield. Soon after these areas were completed a significant amount of false alarms were being recorded. This resulted in finding no enemy presence at the alarm trigger point. Due to the significant cost of ammunition being expended on these false-positive events, it was decided to curtail the rapid response on these areas in 1975. An ongoing Cordon Sanitaire review shelved the whole idea of an early warning system shortly thereafter.

And so ended the Cordon Sanitaire early warning system.

I do not know how effective these measures were as I never encountered them during my time serving in the Rhodesian Corps of Engineers. Personally I do not think the electronic system was as successful as the planners initially thought it would be and with the Rhodesian economy heavily burdened by sanctions and an ever-increasing defence budget there was little chance of any project surviving unless it showed significant success indicators (body count, infiltration mitigation, etc.).

I located the following on the issafrica.org website.  They seem to confirm in some ways parts of the foregoing:


I will continue to seek further sources to help unravel this interesting and little known subject.

Please also have a look at my website dedicated to Rhodesian and South African Military Engineers.  Please join us on the forums by using the following link:



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Mukumbura: The Arrival

December 31, 2013

We always arrived at Mukumbura towards late afternoon.  This was dodgy for a number of reasons.

Firstly, travelling towards evening on roads in any of the operational areas was not recommended.  The gooks liked to ambush at these times so they could slink away into the shadows quickly with very little threat of a follow-up in the darkness.  Our choppers did not usually fly at night in those days so Fire-Force and Casevac support were problematic and if someone was injured they were in a serious situation.  Additionally it was never good to get into base too late in the day or early evening due to the possibility of a last-light attack on the camp.

Secondly, passengers on these long trips may also have become tired and having lost concentration and alertness (the nodding-dog syndrome) became easy prey for gooks lying in wait with evil intent.

Most importantly of all was that dinner would probably have been gobbled up in it’s entirety by the personnel already in the base (thus two squashed hamburgers and a sticky Chelsea bun in my pocket from the Mount Darwin WVS canteen mentioned in previous post).

On arrival at the Mukumbura Engineer camp we would be shown where we would be sleeping for the next 8 or so weeks and given a security brief by one of the senior members of the base HQ element.  On my initial trip to Mukumbura there was a Regular Army Lieutenant running the operations with a Territorial Force Sergeant as his right hand man.  Little did I know at the time but the Lieutenant was to become one of the legends of the Rhodesian Engineers.

His name was Charlie Small.

After we had stowed our kit in our accommodation and had our brief we moved to the base perimeter stand-to positions.  These positions were located all around the camp and were lightly fortified with sandbags and berms.  They all had defined arcs-of-fire to cover the most likely enemy approaches.  Each evening at last-light and each morning at first-light we all went to our allocated stand-to positions to repel any attack or assault by the gooks.  These were the times they favoured for such attacks which could take the form of a stand-off mortar bombardment or a small-arms shoot-out from an appropriate distance.  I was to have first hand experience of these attacks in the future so remain a firm believer in the value of stand-to activities.  Stand-to normally lasted for about 30 minutes.

Our camp consisted of tents, bunkers to duck into in case of a mortar attack, a medical post, HQ area, kitchen/mess area, and an explosives/ammunition storage area.  We also had the pleasure of having Tsetse Fly Control personnel on the camp.  I will discuss these gentlemen in a later post but they were a good bunch of blokes and great characters who worked very closely with us on Cordon Sanitaire.

Our next mission was to learn the science of mine-laying and I will cover this in the next post.

Here is a video taken during Operation Hurricane.  Mukumbura Engineer camp was in this ops area: