Where Mountains Move: The Story of Chagai
By Rai Muhammad Saleh Azam
"Great deeds are done when men and mountains meet; this is not done by jostling in the street." (William Blake)
Pakistan crossed the nuclear threshold to become a declared nuclear weapons state on 28 May 1998 after it detonated five nuclear devices in the Ras Koh Hills in Chagai, Balochistan.
Chagai's nexus with Pakistan's nuclear weapons programme first became known to the Pakistani public and the world back in 1994 when a book, Critical Mass, written by William E. Burrows and Robert Windrem was first published. (1)
However, the story goes further than that.
The story of Chagai began in Quetta, Balochistan in 1976 when Brig. Muhammad Sarfaraz, Chief of Staff at 5 Corps Headquarters received a transmission from the Pakistan Army General Headquarters (GHQ), Rawalpindi. The message directed the Corps Commander to make available an Army helicopter to a forthcoming team of scientists from the Pakistan Atomic Energy Commission (PAEC) for operational reconnaissance of some areas in Balochistan.
The PAEC team comprising of Dr. Ishfaq Ahmed, Member (Technical) and Dr. Ahsan Mubarak landed at Quetta and were provided the helicopter as per the GHQ instructions. Over a span of three days, the PAEC scientists reconnoitred, several times, the area between Turbat, Awaran and Khusdar to the south, Naukundi to the east and Kharan to the west.
Their objective was to find a suitable location for an underground nuclear test, preferably a mountain.
After a hectic and careful search they found a mountain which matched their specifications. This was a 185-metre base-to-summit high granite mountain in the Ras Koh Hills in the Chagai Division of Balochistan which, at their highest point, rise to a height of 9,367 feet (3,009 metres) above sea level. The Ras Koh Hills are independent of and should not be confused with the Chagai Hills further north on the Pak-Afghan border, in which, to date, no nuclear test activity has taken place.
The PAEC requirement was that the mountain should be "bone dry" and capable of withstanding a 20 kilotonne nuclear explosion from the inside. Tests were conducted to measure the water content of the mountains and the surrounding area and to measure the capability of the mountain's rock to withstand a nuclear test. Once this was confirmed, Dr. Ishfaq Ahmed commenced work on a three-dimensional survey of the area with the help of the Geological Survey of Pakistan (GSP).
This survey took one year to conduct and, in 1977, it was decided that the proposed tunnel to be bored in the mountain should have an overburden of a 700 metre high mountain over it, thus sufficient to withstand 20-40 kilotonnes of nuclear force. In the same year, Brig. Muhammad Sarfaraz, who, in the interim, had been posted to GHQ Rawalpindi, was summoned by President Zia-ul-Haq and was told that the PAEC wanted to lease him from the Army to carry out work related to the Pakistan nuclear programme. This resulted in the creation of an organization called the Special Development Works (SDW), a subsidiary of the PAEC but directly reporting to the Chief of the Army Staff and entrusted with the task of preparing Pakistan's nuclear test sites. Brig. Sarfaraz, for all practical purposes, headed the SDW, a nuclear variant of the Pakistan Army's famous Frontier Works Organization (FWO) which, along with the Chinese, built the Karakorum Highway in the 1966-78 period.
The primary task of SDW was to prepare underground test sites (both horizontal and vertical shaft tunnels) for 20-kilotonne nuclear devices, along with all the allied infrastructure and facilities. The sites had to be designed in such a way that they could be utilized at short notice (in less than a week) and were to be completed by 31 December 1979 at the latest.
After a series of meetings between SDW and PAEC officials and the President of Pakistan, it was decided that SDW should prepare 2-3 separate sites. Therefore, a second site for a vertical shaft tunnel was prepared in the Kharan Desert, at a barren location approximately 150 kilometres west of the Ras Koh test site, located in a rolling sandy desert valley lined with sand ridges between the Ras Koh Hills to the north and the Siahan Range to the south.
Ras Koh literally means, "Gateway to the Mountains" in Urdu, Arabic and Farsi. The Balochistan Plateau in western Pakistan lies east of the Sulaiman and Kirthar Ranges, with an average elevation of about 600 meters. Mountains spread in various directions, attaining elevations of 2,000-3,000 meters, though plateaus and basins predominate the scene. The Toba Kakar Range and Chagai Hills in the north form the border of Pakistan with Afghanistan. The mountains and hills are carved by innumerable channels which contain water only after rains, though little water reaches the low-lying basins. Numerous alluvial fans are found in the Balochistan Desert. A structural depression separates the Chagai Hills and the Ras Koh Range to the south, consisting of flood plains and areas covered with thin layers of salt. Outside the monsoon zone, Balochistan receives scanty and irregular rainfall (4 inches annually); the temperature is very high in summer and very low in winter. Apart from the Toba Kakar Range, which has scattered juniper, tamarisk and pistachio trees, the other ranges are largely devoid of vegetation. Most of the people, therefore, lead nomadic life, raising camels, sheep and goats. The Siahan Range is in the west-central part of Balochistan, while the coastal Makran Range which skirts the south of Pakistan contains valuable deposits of coal, iron, gas, chromite, copper and several other minerals. Balochistan is fortunate to have considerable mineral wealth of natural gas, coal, chromite, lead, sulphur and marble.
The Kharan Desert, also known as the "Sandy Desert" or "Balochistan Desert", is located in north-west Balochistan. Pakistan, a mostly dry country characterized by extremes of altitude and temperature, has three main river basins: Indus, Kharan and Makran. The Indus Plain extends principally along the eastern side of the river, and the Balochistan Plateau lies to the south-west. Four other topographic areas are the narrow coastal plain bordering the Arabian Sea; the Thar Desert on the border with India; the mountains of the north and north-west; and the Kharan Basin, to the west of the Balochistan Plateau. The Kharan Basin is known as a closed basin because the entire basin's catchment water is used for agriculture and domestic requirements. The Kharan Desert area consists of shifting sand dunes with an underlying pebble-conglomerate floor. The moving dunes reach heights of between 15 and 30 meters. Level areas between the dunes are a hard-topped pan when dry and a treacherous, sandy-clay mush when wet. The barren wastes that occupy almost half of Iran, with its continuation into Kharan in Pakistan, form a continuous stretch of absolute barrenness from the alluvial fans of the Alborz Mountains in the north of Iran to the edge of the plateau in Balochistan, Pakistan, more than 1,200 km to the south-east. In altitude these central deserts slope from about 1,000 m in the north to about 250 m on in the south-west. Average annual rainfall throughout these deserts is well under 100 mm. The desert includes areas of inland drainage and dry lakes (hamuns). The Gowd-e-Zereh (lake basin) in Iran, which occasionally receives excess drainage, is separated from Kharan in Pakistan by low hills, which, with the highlands around the extinct volcano of Koh-e-Tafta'n, cause the Mashkel River to form a lake. The surface of the Hamun-e-Mashkhel, which is some 85 kilometres long and 35 kilometres wide, is littered with sun-cracked clay, oxidized pebbles, salty marshes and crescent-shaped moving sand dunes. The area is known particularly for its constant mirages and sudden severe sandstorms.
Subsequently, the Chagai-Ras Koh-Kharan areas became restricted entry zones and were closed to the public, prompting rumours that Pakistan had given airbases to the United States. The fact that USAID had set up an office in Turbat, Balochistan only added fuel to such rumours.
A 3,325 feet long horizontal shaft tunnel was bored in the Ras Koh Hills, which was 8-9 feet in diameter and was shaped like a fishhook for it to be self-sealing. The vertical shaft tunnel at Kharan was 300 feet by 200 feet and was L-shaped. Both test sites had an array of extensive cables, sensors and monitoring stations. In addition to the main tunnels, SDW built 24 cold test sites, 46 short tunnels and 35 underground accommodations for troops and command, control and monitoring facilities. At Ras Koh, some of these were located inside the granite mountains.
Both the nuclear test sites at Ras Koh and Kharan took 2-3 years to prepare and were completed by 1980, before Pakistan acquired the capability to develop a nuclear weapon. This showed both confidence and resolve in Pakistan's nuclear programme as well as faith in Almighty God.
In March 1974, Hafeez Qureshi, who at the time was heading the Radiation and Isotope Applications Division (RIAD) at the Pakistan Institute of Science & Technology (PINSTECH) at Nilore, 23 kilometres south-east of Islamabad, and a mechanical engineer par excellence, was summoned by the then Chairman of the PAEC, Munir Ahmad Khan in a meeting that was attended, among others, by Dr. Abdus Salam, then Adviser for Science and Technology to the Government of Pakistan and Dr. Riaz-ud-Din, Member (Technical), PAEC. Qureshi was told that he join hands on a project of national importance with another expert, Dr. Zaman Sheikh, then working with the Defence Science & Technology Organization (DESTO), located 15 kilometres east of Islamabad at the foot of the scenic Murree Hills. The word "bomb" was never used in the meeting but Qureshi knew exactly what he was being asked to do. Their task would be to build the mechanics of Pakistan's first atomic bomb. The project would be located at Wah, appropriately next to the main and largest complex of the Pakistan Ordnance Factories (POF), strategically close to the hills and conveniently close to the capital, Islamabad.
The work at Wah began under the code name of "Research & Development" (R&D) and Qureshi, Zaman and their team of scientists and engineers came to be known as "The Wah Group". Initial work was limited to research and development of the explosives to be used in the nuclear device. However, the terms of reference subsequently expanded to include chemical, mechanical and precision engineering and triggering mechanisms. They procured equipment for reverse-engineering from foreign sources where they could and developed their own technology indigenously where restrictions prevented the purchase of equipment from abroad.
Pakistan's first cold test of its nuclear device was carried out on 11 March 1983 in the Kirana Hills near Sargodha, home of the Pakistan Air Force's main air base and the Central Ammunition Depot (CAD). Cold Test (CT) is a means of testing the working of a nuclear device without a nuclear explosion and the resultant radiation. This is achieved by triggering an actual bomb by initiating a chain reaction but without the radioactive fissile material needed to detonate it. The test was overseen by Dr. Ishfaq Ahmed.
The tunnels at Kirana Hills, Sargodha are reported to have been bored after those at Chagai, i.e. sometime between 1979 and 1983. As in Chagai, the tunnels at Kirana Hills had been bored and then sealed and this task was also undertaken by SDW.
Prior to the cold tests, an advance team was sent to de-seal, open and clean the tunnels and to make sure the tunnels were clear of the wild boars that are found in abundance in the Sargodha region. The damage which these wild boars could do to men and equipment could not be understated when one such intrepid wild boar later cost the Pakistan Air Force (PAF) an F-16 when a direct impact between the aircraft and the wild boar in the middle of the runway resulted in the aircraft's front undercarriage being sheared off as it came in to land at Sargodha Air Base. Luckily, the pilot ejected with minor injuries thanks to the aircraft's Zero-Zero ejection seat. The $20 million F-16 was, however, severely damaged and had to be written off. It is surprising that the otherwise highly trained and professional PAF did not deem it fit and appropriate to fence the Sargodha Air Base complex. This would have cost the PAF much less than $20 million, which is the eventual price it had to pay for its failure in doing so.
After clearing of the tunnels, a PAEC diagnostic team headed by Dr. Samar Mubarakmand arrived on the scene with trailers fitted with computers and diagnostic equipment. This was followed by the arrival of the Wah Group with the actual nuclear device, in sub-assembly form. The device was assembled and then placed inside the tunnel. A monitoring system was set up with around 20 cables linking various parts of the device with oscillators in diagnostic vans parked near the Kirana Hills. The Wah Group had indigenously developed the explosive HMX (His Majesty's Explosive) which was used to trigger the device.
The device was tested using the "push-button" technique as opposed to the "radio-link" technique used at Chagai fourteen years later. The first test was to see whether the triggering mechanism created the necessary neutrons which would start a fission chain reaction in the real bomb. However, when the button was pushed, most of the wires connecting the device to the oscillators were severed due to errors committed in the preparation of the cables. At first, it was thought that the device had malfunctioned but closer scrutiny of two of the oscillators confirmed that the neutrons had indeed come out and a chain reaction had taken place. Pakistan's first cold test of a nuclear device had been successful and 11 March became a red letter day in the calendar of the Pakistan nuclear programme. A second cold test was undertaken soon afterwards which was witnessed by, among others, Ghulam Ishaq Khan, Finance Minister, Lt. Gen. K.M. Arif, Chief of Staff and Munir Ahmed Khan, Chairman, PAEC.
The need to improve and perfect the design of Pakistan's first nuclear device required constant testing. As a result, between 1983 and 1990, the Wah Group conducted more than 24 cold tests of the nuclear device at Kirana Hills with the help of mobile diagnostic equipment. These tests were carried out in 24 horizontal-shaft tunnels measuring 100-150 feet in length which were bored inside the Kirana Hills. Later due to excessive US intelligence and satellite focus on the Kirana Hills site, it was abandoned and the CT facility was shifted to the Kala-Chitta Range.
By March 1984, Kahuta Research Laboratories (KRL) had independently carried out its own cold tests of its nuclear device near Kahuta.
Also, during the 1983-1990 period, the Wah Group went on to design and develop an atomic bomb small enough to be carried on the wing of a small fighter such as the F-16. It worked alongside the PAF to evolve and perfect delivery techniques of the nuclear bomb including 'conventional free-fall', 'loft bombing', 'toss bombing' and 'low-level laydown' attack techniques using combat aircraft. Today, the PAF has perfected all four techniques of nuclear weapons delivery using F-16 and Mirage-V combat aircraft indigenously configured to carry nuclear weapons.
"Great deeds are done when men and mountains meet; this is not done by jostling in the street." (William Blake)
Pakistan crossed the nuclear threshold to become a declared nuclear weapons state on 28 May 1998 after it detonated five nuclear devices in the Ras Koh Hills in Chagai, Balochistan.
Chagai's nexus with Pakistan's nuclear weapons programme first became known to the Pakistani public and the world back in 1994 when a book, Critical Mass, written by William E. Burrows and Robert Windrem was first published. (1)
However, the story goes further than that.
CHAGAI: THE BACKGROUND
The story of Chagai began in Quetta, Balochistan in 1976 when Brig. Muhammad Sarfaraz, Chief of Staff at 5 Corps Headquarters received a transmission from the Pakistan Army General Headquarters (GHQ), Rawalpindi. The message directed the Corps Commander to make available an Army helicopter to a forthcoming team of scientists from the Pakistan Atomic Energy Commission (PAEC) for operational reconnaissance of some areas in Balochistan.
The PAEC team comprising of Dr. Ishfaq Ahmed, Member (Technical) and Dr. Ahsan Mubarak landed at Quetta and were provided the helicopter as per the GHQ instructions. Over a span of three days, the PAEC scientists reconnoitred, several times, the area between Turbat, Awaran and Khusdar to the south, Naukundi to the east and Kharan to the west.
Their objective was to find a suitable location for an underground nuclear test, preferably a mountain.
After a hectic and careful search they found a mountain which matched their specifications. This was a 185-metre base-to-summit high granite mountain in the Ras Koh Hills in the Chagai Division of Balochistan which, at their highest point, rise to a height of 9,367 feet (3,009 metres) above sea level. The Ras Koh Hills are independent of and should not be confused with the Chagai Hills further north on the Pak-Afghan border, in which, to date, no nuclear test activity has taken place.
The PAEC requirement was that the mountain should be "bone dry" and capable of withstanding a 20 kilotonne nuclear explosion from the inside. Tests were conducted to measure the water content of the mountains and the surrounding area and to measure the capability of the mountain's rock to withstand a nuclear test. Once this was confirmed, Dr. Ishfaq Ahmed commenced work on a three-dimensional survey of the area with the help of the Geological Survey of Pakistan (GSP).
This survey took one year to conduct and, in 1977, it was decided that the proposed tunnel to be bored in the mountain should have an overburden of a 700 metre high mountain over it, thus sufficient to withstand 20-40 kilotonnes of nuclear force. In the same year, Brig. Muhammad Sarfaraz, who, in the interim, had been posted to GHQ Rawalpindi, was summoned by President Zia-ul-Haq and was told that the PAEC wanted to lease him from the Army to carry out work related to the Pakistan nuclear programme. This resulted in the creation of an organization called the Special Development Works (SDW), a subsidiary of the PAEC but directly reporting to the Chief of the Army Staff and entrusted with the task of preparing Pakistan's nuclear test sites. Brig. Sarfaraz, for all practical purposes, headed the SDW, a nuclear variant of the Pakistan Army's famous Frontier Works Organization (FWO) which, along with the Chinese, built the Karakorum Highway in the 1966-78 period.
The primary task of SDW was to prepare underground test sites (both horizontal and vertical shaft tunnels) for 20-kilotonne nuclear devices, along with all the allied infrastructure and facilities. The sites had to be designed in such a way that they could be utilized at short notice (in less than a week) and were to be completed by 31 December 1979 at the latest.
After a series of meetings between SDW and PAEC officials and the President of Pakistan, it was decided that SDW should prepare 2-3 separate sites. Therefore, a second site for a vertical shaft tunnel was prepared in the Kharan Desert, at a barren location approximately 150 kilometres west of the Ras Koh test site, located in a rolling sandy desert valley lined with sand ridges between the Ras Koh Hills to the north and the Siahan Range to the south.
RAS KOH HILLS: THE TOPOGRAPHY
Ras Koh literally means, "Gateway to the Mountains" in Urdu, Arabic and Farsi. The Balochistan Plateau in western Pakistan lies east of the Sulaiman and Kirthar Ranges, with an average elevation of about 600 meters. Mountains spread in various directions, attaining elevations of 2,000-3,000 meters, though plateaus and basins predominate the scene. The Toba Kakar Range and Chagai Hills in the north form the border of Pakistan with Afghanistan. The mountains and hills are carved by innumerable channels which contain water only after rains, though little water reaches the low-lying basins. Numerous alluvial fans are found in the Balochistan Desert. A structural depression separates the Chagai Hills and the Ras Koh Range to the south, consisting of flood plains and areas covered with thin layers of salt. Outside the monsoon zone, Balochistan receives scanty and irregular rainfall (4 inches annually); the temperature is very high in summer and very low in winter. Apart from the Toba Kakar Range, which has scattered juniper, tamarisk and pistachio trees, the other ranges are largely devoid of vegetation. Most of the people, therefore, lead nomadic life, raising camels, sheep and goats. The Siahan Range is in the west-central part of Balochistan, while the coastal Makran Range which skirts the south of Pakistan contains valuable deposits of coal, iron, gas, chromite, copper and several other minerals. Balochistan is fortunate to have considerable mineral wealth of natural gas, coal, chromite, lead, sulphur and marble.
KHARAN DESERT: THE TOPOGRAPHY
The Kharan Desert, also known as the "Sandy Desert" or "Balochistan Desert", is located in north-west Balochistan. Pakistan, a mostly dry country characterized by extremes of altitude and temperature, has three main river basins: Indus, Kharan and Makran. The Indus Plain extends principally along the eastern side of the river, and the Balochistan Plateau lies to the south-west. Four other topographic areas are the narrow coastal plain bordering the Arabian Sea; the Thar Desert on the border with India; the mountains of the north and north-west; and the Kharan Basin, to the west of the Balochistan Plateau. The Kharan Basin is known as a closed basin because the entire basin's catchment water is used for agriculture and domestic requirements. The Kharan Desert area consists of shifting sand dunes with an underlying pebble-conglomerate floor. The moving dunes reach heights of between 15 and 30 meters. Level areas between the dunes are a hard-topped pan when dry and a treacherous, sandy-clay mush when wet. The barren wastes that occupy almost half of Iran, with its continuation into Kharan in Pakistan, form a continuous stretch of absolute barrenness from the alluvial fans of the Alborz Mountains in the north of Iran to the edge of the plateau in Balochistan, Pakistan, more than 1,200 km to the south-east. In altitude these central deserts slope from about 1,000 m in the north to about 250 m on in the south-west. Average annual rainfall throughout these deserts is well under 100 mm. The desert includes areas of inland drainage and dry lakes (hamuns). The Gowd-e-Zereh (lake basin) in Iran, which occasionally receives excess drainage, is separated from Kharan in Pakistan by low hills, which, with the highlands around the extinct volcano of Koh-e-Tafta'n, cause the Mashkel River to form a lake. The surface of the Hamun-e-Mashkhel, which is some 85 kilometres long and 35 kilometres wide, is littered with sun-cracked clay, oxidized pebbles, salty marshes and crescent-shaped moving sand dunes. The area is known particularly for its constant mirages and sudden severe sandstorms.
Subsequently, the Chagai-Ras Koh-Kharan areas became restricted entry zones and were closed to the public, prompting rumours that Pakistan had given airbases to the United States. The fact that USAID had set up an office in Turbat, Balochistan only added fuel to such rumours.
A 3,325 feet long horizontal shaft tunnel was bored in the Ras Koh Hills, which was 8-9 feet in diameter and was shaped like a fishhook for it to be self-sealing. The vertical shaft tunnel at Kharan was 300 feet by 200 feet and was L-shaped. Both test sites had an array of extensive cables, sensors and monitoring stations. In addition to the main tunnels, SDW built 24 cold test sites, 46 short tunnels and 35 underground accommodations for troops and command, control and monitoring facilities. At Ras Koh, some of these were located inside the granite mountains.
Both the nuclear test sites at Ras Koh and Kharan took 2-3 years to prepare and were completed by 1980, before Pakistan acquired the capability to develop a nuclear weapon. This showed both confidence and resolve in Pakistan's nuclear programme as well as faith in Almighty God.
THE WAH GROUP: DESIGNERS AND MANUFACTURERS OF PAKISTAN'S NUCLEAR DEVICE
In March 1974, Hafeez Qureshi, who at the time was heading the Radiation and Isotope Applications Division (RIAD) at the Pakistan Institute of Science & Technology (PINSTECH) at Nilore, 23 kilometres south-east of Islamabad, and a mechanical engineer par excellence, was summoned by the then Chairman of the PAEC, Munir Ahmad Khan in a meeting that was attended, among others, by Dr. Abdus Salam, then Adviser for Science and Technology to the Government of Pakistan and Dr. Riaz-ud-Din, Member (Technical), PAEC. Qureshi was told that he join hands on a project of national importance with another expert, Dr. Zaman Sheikh, then working with the Defence Science & Technology Organization (DESTO), located 15 kilometres east of Islamabad at the foot of the scenic Murree Hills. The word "bomb" was never used in the meeting but Qureshi knew exactly what he was being asked to do. Their task would be to build the mechanics of Pakistan's first atomic bomb. The project would be located at Wah, appropriately next to the main and largest complex of the Pakistan Ordnance Factories (POF), strategically close to the hills and conveniently close to the capital, Islamabad.
The work at Wah began under the code name of "Research & Development" (R&D) and Qureshi, Zaman and their team of scientists and engineers came to be known as "The Wah Group". Initial work was limited to research and development of the explosives to be used in the nuclear device. However, the terms of reference subsequently expanded to include chemical, mechanical and precision engineering and triggering mechanisms. They procured equipment for reverse-engineering from foreign sources where they could and developed their own technology indigenously where restrictions prevented the purchase of equipment from abroad.
KIRANA HILLS, SARGODHA: THE COLD TESTS
Pakistan's first cold test of its nuclear device was carried out on 11 March 1983 in the Kirana Hills near Sargodha, home of the Pakistan Air Force's main air base and the Central Ammunition Depot (CAD). Cold Test (CT) is a means of testing the working of a nuclear device without a nuclear explosion and the resultant radiation. This is achieved by triggering an actual bomb by initiating a chain reaction but without the radioactive fissile material needed to detonate it. The test was overseen by Dr. Ishfaq Ahmed.
The tunnels at Kirana Hills, Sargodha are reported to have been bored after those at Chagai, i.e. sometime between 1979 and 1983. As in Chagai, the tunnels at Kirana Hills had been bored and then sealed and this task was also undertaken by SDW.
Prior to the cold tests, an advance team was sent to de-seal, open and clean the tunnels and to make sure the tunnels were clear of the wild boars that are found in abundance in the Sargodha region. The damage which these wild boars could do to men and equipment could not be understated when one such intrepid wild boar later cost the Pakistan Air Force (PAF) an F-16 when a direct impact between the aircraft and the wild boar in the middle of the runway resulted in the aircraft's front undercarriage being sheared off as it came in to land at Sargodha Air Base. Luckily, the pilot ejected with minor injuries thanks to the aircraft's Zero-Zero ejection seat. The $20 million F-16 was, however, severely damaged and had to be written off. It is surprising that the otherwise highly trained and professional PAF did not deem it fit and appropriate to fence the Sargodha Air Base complex. This would have cost the PAF much less than $20 million, which is the eventual price it had to pay for its failure in doing so.
After clearing of the tunnels, a PAEC diagnostic team headed by Dr. Samar Mubarakmand arrived on the scene with trailers fitted with computers and diagnostic equipment. This was followed by the arrival of the Wah Group with the actual nuclear device, in sub-assembly form. The device was assembled and then placed inside the tunnel. A monitoring system was set up with around 20 cables linking various parts of the device with oscillators in diagnostic vans parked near the Kirana Hills. The Wah Group had indigenously developed the explosive HMX (His Majesty's Explosive) which was used to trigger the device.
The device was tested using the "push-button" technique as opposed to the "radio-link" technique used at Chagai fourteen years later. The first test was to see whether the triggering mechanism created the necessary neutrons which would start a fission chain reaction in the real bomb. However, when the button was pushed, most of the wires connecting the device to the oscillators were severed due to errors committed in the preparation of the cables. At first, it was thought that the device had malfunctioned but closer scrutiny of two of the oscillators confirmed that the neutrons had indeed come out and a chain reaction had taken place. Pakistan's first cold test of a nuclear device had been successful and 11 March became a red letter day in the calendar of the Pakistan nuclear programme. A second cold test was undertaken soon afterwards which was witnessed by, among others, Ghulam Ishaq Khan, Finance Minister, Lt. Gen. K.M. Arif, Chief of Staff and Munir Ahmed Khan, Chairman, PAEC.
The need to improve and perfect the design of Pakistan's first nuclear device required constant testing. As a result, between 1983 and 1990, the Wah Group conducted more than 24 cold tests of the nuclear device at Kirana Hills with the help of mobile diagnostic equipment. These tests were carried out in 24 horizontal-shaft tunnels measuring 100-150 feet in length which were bored inside the Kirana Hills. Later due to excessive US intelligence and satellite focus on the Kirana Hills site, it was abandoned and the CT facility was shifted to the Kala-Chitta Range.
By March 1984, Kahuta Research Laboratories (KRL) had independently carried out its own cold tests of its nuclear device near Kahuta.
Also, during the 1983-1990 period, the Wah Group went on to design and develop an atomic bomb small enough to be carried on the wing of a small fighter such as the F-16. It worked alongside the PAF to evolve and perfect delivery techniques of the nuclear bomb including 'conventional free-fall', 'loft bombing', 'toss bombing' and 'low-level laydown' attack techniques using combat aircraft. Today, the PAF has perfected all four techniques of nuclear weapons delivery using F-16 and Mirage-V combat aircraft indigenously configured to carry nuclear weapons.
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