So You Think You Have Problems!
Phil Robinson of Exchem Explosives’ technical service department recalls one of his more unusual shotfiring training courses
When an enquiry came in to run a quarry shotfiring training course on St Helena it was with some degree of excitement and anticipation that the discussions began. The island of St Helena is situated in the South Atlantic Ocean, some 1,700 miles north-west of Capetown and 700 miles south-east of Ascension Island, and is one of the remotest places in the world. The economy of the island is heavily dependant on aid from the UK, however there is a drive to reduce this dependency on overseas aid and to encourage the development of the private sector. To this end the St Helena Development Agency was set up in 1995 through joint funding from the St Helena and UK governments.
There are three quarries on the island. The quarry on Donkey Plain was owned by the Government’s Public Works and Services Department until 1999 but is now operated by a private sector business. There is another quarry near Turks Cap and the third is situated near to the Millennium Forest and Prosperous Plain. All three sites operate at a low level of output, far below that of the smallest UK quarry, most of which is supplied as material for road repairs and for processing into building materials.
The Public Works and Services Department is responsible for the storage, transportation and supervision of explosives and blasting operations on St Helena. Small-diameter nitroglycerine-based explosive is available for use in the quarries and the blasting regime on the island requires two qualified shotfirers to be present whenever blasts are carried out. As one of the existing shotfirers had retired, leaving only two qualified government employees, there was therefore a requirement for training to be provided.
The St Helena Development Agency’s managing director contacted the Institute of Explosives Engineers to arrange for a trainer to run a course to the standards that apply in the UK. The course would be offered to both private sector and government employees. It was soon discovered that there is no law on quarrying operations in St Helena, however, as with many other activities, the island tends to follow UK legislation in such matters. This meant that, in principle, the island’s shotfirers would be operating under the Quarries Regulations, 1999, and that the training provided would need to be to the standards required of UK-based quarry shotfirers.
Photographs of the three quarries on the island showed that drilling is carried out using hand-held air-powered rigs. A hole diameter of 41mm is used and face heights in the three quarries vary from around 2m to 7m. It was difficult to determine very much about the rock from the photographs but it is known to be of volcanic origin and very variable in quality.
The St Helena Development Agency organized the course on the island and paid for the trainer to get there to provide the appropriate teaching. This is where the first difficulty arose, as the only access to the island at present is by the RMS St Helena, which sails from Cardiff and calls at the Azores, Capetown, St Helena and Ascension Island. This is St Helena’s only supply route for passengers and cargo, including explosive products. It was decided that the most sensible route for travel — one that would allow enough time on the island to run the course — would necessitate flying to Capetown and then sailing from there to St Helena, a journey taking seven days. From St Helena the supply ship sails on to Ascension Island before returning for the return voyage to Capetown eight days later. Thus, from home in the UK to the island and back again would take a total of 22 days!
A study is currently being carried out into the feasibility of providing air access to the island. If this project goes ahead quarry output would have to be raised during the construction phase of the airport and associated amenities, which may be linked to a sporting activity, such as golf or shooting, and centred on a hotel complex.
Discussions continued and it became apparent that the interest in blasting was such that around 20 people wanted to attend the course; this is on an island that has a resident population of about 5,000. Most of the island’s residents are women, as the men tend to seek jobs overseas where the rates of pay are much higher. About 1,300 St Heleneans work on Ascension Island and in the Falklands, and there is also a small UK-based concentration of islanders around Cheltenham and Swindon. It was, therefore, a fair proportion of the male population of the island that wished to become shotfirers!
The second problem for a UK-based trainer is how to supply the necessary training manuals and ancillary requirements for the course. Thanks to Internet technology, the ‘paper’ parts of the course materials were emailed to the island and printed by the Government printers in Jamestown — St Helena’s only town. Examinations papers were arranged by the St Helena Development Agency, through EPIC, and these were sent out by diplomatic bag.
Thus it was that the author set out from the UK at the end of June to arrive on the island seven days later. With little time to settle in, the course began on time at 1.00pm on the afternoon of arrival. It soon became apparent in discussions with the course attendees that the knowledge and information about products and techniques that are taken for granted in the UK had not been available on the island up to now; everything taught on the course appeared to be new.
It should be noted that all explosive products are purchased by the St Helena government and remain under its control. As a result the quarry operators are dependant on the government for the choice of explosive products and for information relating to these products. The individual quarries do not have direct access to explosive materials.
Midway through the week-long course there was a visit to the island’s explosive store, and two demonstration blasts were carried out at Donkey Plain Quarry. The store proved to be very interesting as it is located in an old powder magazine at one of the island’s many forts, which were originally built to repel invaders during the 18th century.
It was known that, at some time in the past, Exchem had supplied explosive material to the Government of St Helena and inspection of the store revealed where this old delivery had ended up.
Blasting is carried out using Gelamex with initiation by means of surface and in-hole Pentaflex 12 detonating cord. The lines of holes are fired using short-delay electric detonators attached to the end of the detonating cord trunkline used to fire each line of holes. At the time of the inspection the best material available for use out of the 32mm x 200mm cartridges of Gelamex (Dynaroc5) turned out to be some 15 months old. Further inspection also revealed three sources of electric detonators — South Africa, UK and Germany — and again these items proved to be quite old.
An alternative firing method sometimes used makes use of a safety fuse capped with a plain detonator to initiate the detonating cord trunkline on the first line of holes. Each subsequent line of holes in the blast is delayed using detonating relays containing a 17ms delay time. The two demonstration blasts made use of both methods.
The reason that the blasts do not use individually delayed holes is purely due to the cost of detonators. On St Helena, each 3m short-delay electric detonator costs approximately 10 times as much as the equivalent product in the UK!
The first blast used two lines of holes (a total of 17 had been pre-drilled to a depth of 3.8m), while the second had three rows of 3.8m deep holes. These had been drilled in the usual way — without the benefit of laser profiling or any other measuring techniques etc.
Two successful blasts were carried out safely and measurements were taken to form the basis of a blast plan to allow the development of a simplified specification that the island’s quarry operators could use in the future.
Exams were held at the conclusion of the training course, with the head teacher of the local school handling the security arrangements for the examination and the completed papers being returned to the UK for marking via the next available sailing of the RMS St Helena.
Despite all the difficulties and lack of resources, St Helena and its people made a lasting impression on the author, who intends to keep in contact with the island to keep an eye on progress with quarries, legislation and the development of safe codes of practice.
When an enquiry came in to run a quarry shotfiring training course on St Helena it was with some degree of excitement and anticipation that the discussions began. The island of St Helena is situated in the South Atlantic Ocean, some 1,700 miles north-west of Capetown and 700 miles south-east of Ascension Island, and is one of the remotest places in the world. The economy of the island is heavily dependant on aid from the UK, however there is a drive to reduce this dependency on overseas aid and to encourage the development of the private sector. To this end the St Helena Development Agency was set up in 1995 through joint funding from the St Helena and UK governments.
There are three quarries on the island. The quarry on Donkey Plain was owned by the Government’s Public Works and Services Department until 1999 but is now operated by a private sector business. There is another quarry near Turks Cap and the third is situated near to the Millennium Forest and Prosperous Plain. All three sites operate at a low level of output, far below that of the smallest UK quarry, most of which is supplied as material for road repairs and for processing into building materials.
The Public Works and Services Department is responsible for the storage, transportation and supervision of explosives and blasting operations on St Helena. Small-diameter nitroglycerine-based explosive is available for use in the quarries and the blasting regime on the island requires two qualified shotfirers to be present whenever blasts are carried out. As one of the existing shotfirers had retired, leaving only two qualified government employees, there was therefore a requirement for training to be provided.
The St Helena Development Agency’s managing director contacted the Institute of Explosives Engineers to arrange for a trainer to run a course to the standards that apply in the UK. The course would be offered to both private sector and government employees. It was soon discovered that there is no law on quarrying operations in St Helena, however, as with many other activities, the island tends to follow UK legislation in such matters. This meant that, in principle, the island’s shotfirers would be operating under the Quarries Regulations, 1999, and that the training provided would need to be to the standards required of UK-based quarry shotfirers.
Photographs of the three quarries on the island showed that drilling is carried out using hand-held air-powered rigs. A hole diameter of 41mm is used and face heights in the three quarries vary from around 2m to 7m. It was difficult to determine very much about the rock from the photographs but it is known to be of volcanic origin and very variable in quality.
The St Helena Development Agency organized the course on the island and paid for the trainer to get there to provide the appropriate teaching. This is where the first difficulty arose, as the only access to the island at present is by the RMS St Helena, which sails from Cardiff and calls at the Azores, Capetown, St Helena and Ascension Island. This is St Helena’s only supply route for passengers and cargo, including explosive products. It was decided that the most sensible route for travel — one that would allow enough time on the island to run the course — would necessitate flying to Capetown and then sailing from there to St Helena, a journey taking seven days. From St Helena the supply ship sails on to Ascension Island before returning for the return voyage to Capetown eight days later. Thus, from home in the UK to the island and back again would take a total of 22 days!
A study is currently being carried out into the feasibility of providing air access to the island. If this project goes ahead quarry output would have to be raised during the construction phase of the airport and associated amenities, which may be linked to a sporting activity, such as golf or shooting, and centred on a hotel complex.
Discussions continued and it became apparent that the interest in blasting was such that around 20 people wanted to attend the course; this is on an island that has a resident population of about 5,000. Most of the island’s residents are women, as the men tend to seek jobs overseas where the rates of pay are much higher. About 1,300 St Heleneans work on Ascension Island and in the Falklands, and there is also a small UK-based concentration of islanders around Cheltenham and Swindon. It was, therefore, a fair proportion of the male population of the island that wished to become shotfirers!
The second problem for a UK-based trainer is how to supply the necessary training manuals and ancillary requirements for the course. Thanks to Internet technology, the ‘paper’ parts of the course materials were emailed to the island and printed by the Government printers in Jamestown — St Helena’s only town. Examinations papers were arranged by the St Helena Development Agency, through EPIC, and these were sent out by diplomatic bag.
Thus it was that the author set out from the UK at the end of June to arrive on the island seven days later. With little time to settle in, the course began on time at 1.00pm on the afternoon of arrival. It soon became apparent in discussions with the course attendees that the knowledge and information about products and techniques that are taken for granted in the UK had not been available on the island up to now; everything taught on the course appeared to be new.
It should be noted that all explosive products are purchased by the St Helena government and remain under its control. As a result the quarry operators are dependant on the government for the choice of explosive products and for information relating to these products. The individual quarries do not have direct access to explosive materials.
Midway through the week-long course there was a visit to the island’s explosive store, and two demonstration blasts were carried out at Donkey Plain Quarry. The store proved to be very interesting as it is located in an old powder magazine at one of the island’s many forts, which were originally built to repel invaders during the 18th century.
It was known that, at some time in the past, Exchem had supplied explosive material to the Government of St Helena and inspection of the store revealed where this old delivery had ended up.
Blasting is carried out using Gelamex with initiation by means of surface and in-hole Pentaflex 12 detonating cord. The lines of holes are fired using short-delay electric detonators attached to the end of the detonating cord trunkline used to fire each line of holes. At the time of the inspection the best material available for use out of the 32mm x 200mm cartridges of Gelamex (Dynaroc5) turned out to be some 15 months old. Further inspection also revealed three sources of electric detonators — South Africa, UK and Germany — and again these items proved to be quite old.
An alternative firing method sometimes used makes use of a safety fuse capped with a plain detonator to initiate the detonating cord trunkline on the first line of holes. Each subsequent line of holes in the blast is delayed using detonating relays containing a 17ms delay time. The two demonstration blasts made use of both methods.
The reason that the blasts do not use individually delayed holes is purely due to the cost of detonators. On St Helena, each 3m short-delay electric detonator costs approximately 10 times as much as the equivalent product in the UK!
The first blast used two lines of holes (a total of 17 had been pre-drilled to a depth of 3.8m), while the second had three rows of 3.8m deep holes. These had been drilled in the usual way — without the benefit of laser profiling or any other measuring techniques etc.
Two successful blasts were carried out safely and measurements were taken to form the basis of a blast plan to allow the development of a simplified specification that the island’s quarry operators could use in the future.
Exams were held at the conclusion of the training course, with the head teacher of the local school handling the security arrangements for the examination and the completed papers being returned to the UK for marking via the next available sailing of the RMS St Helena.
Despite all the difficulties and lack of resources, St Helena and its people made a lasting impression on the author, who intends to keep in contact with the island to keep an eye on progress with quarries, legislation and the development of safe codes of practice.
