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.


On 11 and 13 May 1998, India conducted what it claimed were a total of 5 nuclear tests at Pokhran, Rajasthan near the Pakistan border and declared itself a “nuclear weapons state”. This act by India destabilized the balance of power in South Asia heavily in India’s favour. The dust at Pokhran had yet to settle when high-ranking Indian politicians, government officials and military personnel began issuing provocative statements against Pakistan. India declared that it would thenceforth pursue a “pro-active” policy on Jammu & Kashmir. Pakistan was told to realise the “new geo-political realities in South Asia”. Right-wing allies and elements within the Hindu-supremacist Indian BJP government demanded the Indian invasion and annexation of Azad (Free) Jammu & Kashmir and Pakistan’s Northern Areas.

The underlying message for Pakistan was this “give up your claim on Jammu & Kashmir and become forever subservient to Indian hegemony in South Asia”. India was now the nuclear weapons power and Pakistan wasn’t. Therefore, it is Pakistan which must capitulate on Jammu & Kashmir and only the dictate of India would be allowed in South Asia. In the event of another India-Pakistan War, India would be able to use nuclear weapons if its armed forces were defeated or put in a tight corner. Indian warplanners felt that the use of small battlefield nuclear devices against the Pakistan Army cantonments, armoured and infantry columns and PAF bases and nuclear and military industrial facilities would not meet with an adverse reaction from the world community so long as civilian casualties could be kept to a minimum. This way, India would defeat Pakistan, force its armed forces into a humiliating surrender and occupy and annex the Northern Areas of Pakistan and Azad Jammu & Kashmir. India would then carve up Pakistan into tiny states based on ethnic divisions (and later on, perhaps, absorb them into a ‘Greater India’) and that would be the end of the “Pakistan problem” once and for all.

Such a plan could never be allowed to succeed. In the face of national survival, all other things become secondary. Therefore, it was decided that Pakistan had to go nuclear to guarantee its national survival, its security and its territorial integrity and to deny India what would have become an overwhelming and unchallengable military and strategic advantage over Pakistan. Defence, security and strategic concerns were, therefore, the primary and overriding factors in deciding the course, which Pakistan ultimately took.

Other secondary factors which influenced Pakistan’s decision to go ahead with the tests were (i) to give credibility to Pakistan’s nuclear capability; (ii) to prevent a situation from arising in which India, after misreading or underestimating Pakistan’s nuclear capability, embarks upon any misadventure against Pakistan, thereby increasing the chances of a nuclear war; (iii) to restore the balance of power in South Asia and within the Pakistan-India equation, in the eyes of itself, India and the world; (iii) to deny India unilateral technical advantage that it may have gained from the tests and (iii) to use the opportunity and excuse of the Indian tests without having to attract the harsher censure that Pakistan would inevitably have attracted from the world community had it conducted the tests unilaterally. By conducting the tests in response to those of India, Pakistan sought to dilute global criticism and reaction, which would be divided over both the countries and, to some extent, rightly put the blame on India for initiating the nuclear arms race in South Asia. Tertiary factors included (i) acquiring political, diplomatic and prestige advantages for itself; (ii) increasing Pakistan’s position and status in the Islamic and Arab world, (iii) denying India the political, diplomatic and prestige advantages that would have accrued to it had it become the only nuclear power in South Asia; (iv) diluting India’s position as a nuclear power; and (v) gaining scientific and technological know-how that would help Pakistan in both military and civil applications.


A meeting of the Defence Committee of the Cabinet (DCC) was convened on the morning of 15 May 1998 at the Prime Minister’s Secretariat, Islamabad to discuss the geo-political situation and strategic crisis arising out of the Indian nuclear tests. The meeting was chaired by the Prime Minister of Pakistan, Mian Muhammad Nawaz Sharif who himself was holding the portfolio of defence and attended by the Minister of Foreign Affairs, Gohar Ayub Khan, the Minister of Finance & Economic Affairs, Sartaj Aziz, the Foreign Secretary, Shamshad Ahmed Khan and the three Chiefs of Staff of the Army, Air Force and Navy, namely General Jehangir Karamat, Air Chief Marshal Pervaiz Mehdi Qureshi and Admiral Fasih Bokhari respectively.

Since Dr. Ishfaq Ahmed, Chairman of the PAEC, was, at the time, on a visit to the United States and Canada, the responsibility of giving a technical assessment of the Indian nuclear tests and Pakistan’s preparedness to give a matching response to India fell on the shoulders of Dr. Samar Mubarakmand, Member (Technical), PAEC. Dr. Mubarakmand was in charge of the PAEC’s Directorate of Technical Development (DTD), one of the most secretive organizations in the labyrinth of Pakistan’s nuclear infrastructure, the location of which is still unknown to the world and is one of Pakistan’s best kept secrets. It may be that the DTD is the forerunner of the National Development Complex (NDC), the designers and manufacturers of, among other things, Pakistan’s solid-fuelled Shaheen class of medium and intermediate range ballistic nuclear missile systems. The location of the NDC is not exactly known but it is presumed to be located at Fatehjung, a picturesque area of rolling countryside north-west of Islamabad. Dr. Mubarakmand had supervised several cold tests since 1983 and was responsible for overseeing all of PAEC’s classified projects. Also, in attendance was Dr. A.Q. Khan, Director of the renamed Khan (formerly Kahuta) Research Laboratories (KRL), Kahuta.

There were two points on the DCC’s agenda: Firstly, whether or not Pakistan should carry out nuclear tests in order to respond to India’s nuclear tests? Secondly, if Pakistan does go ahead with the tests then which of the two organizations, PAEC or KRL, should carry out the tests?

The discussions went on for a few hours and encompassed the financial, diplomatic, military, geo-political and national security concerns. Finance Minister Sartaj Aziz was the only person who opposed the tests on financial grounds due to the economic recession, the low foreign exchange reserves of the country and the negative effect of inevitable economic sanctions which would be imposed on Pakistan if it carried out the tests. Prime Minister Nawaz Sharif neither opposed nor proposed the tests. The remainder spoke in favour of conducting the tests.

While giving his technical assessment on behalf of the PAEC, Dr. Mubarakmand said that Pakistan had a modern state-of-the-art international seismic station near the capital, Islamabad, and also had seismic stations located all over Pakistan including at locations near the Pakistan-India border. He said that these seismic stations had recorded only one nuclear device at Pokhran on 11 May 1998 and not three as India was wrongfully claiming. He said that the remaining two, in all probability, had fizzled out, i.e. were failures. He also said that no thermonuclear or hydrogen bomb test was carried out by the Indians on either 11 or 13 May 1998 as none of the yields were large enough for such a test. In all likelihood, the Indians may have attempted a thermonuclear test, but it too had failed. Dr. Mubarakmand added that if it is decided that Pakistan should go ahead with nuclear tests of its own, then the PAEC is fully prepared and capable of carrying out the nuclear tests within 10 days.

Dr. A.Q. Khan, speaking on behalf of KRL, also asserted that KRL was fully prepared and capable of carrying out nuclear tests within 10 days if the orders were given by the DCC. Dr. Khan reminded the DCC that it was KRL which had first enriched uranium, converted it into metal, machined it into semi spheres of metal, designed their own atomic bomb and carried out cold tests on their own. All this was achieved without any help from PAEC. He said that KRL was fully independent in the nuclear field. Dr. Khan went on to say that since it was KRL which first made inroads into the nuclear field, especially in uranium enrichment, for Pakistan, it should, therefore, be given the honour of carrying out Pakistan’s first nuclear tests. He added that KRL would feel let down if wasn’t conferred the privilege of doing so.

Thus, both the PAEC and KRL were equal to the task. However, PAEC had two additional advantages over KRL. Firstly, it was PAEC which had constructed Pakistan’s two nuclear test sites at Chagai, Balochistan. Secondly, PAEC had greater experience than KRL in conducting cold tests.

The DCC meeting concluded without any resolution of the two agenda points.

The Chairman of the PAEC, Dr. Ishfaq Ahmed, cut short his foreign trip and returned to Pakistan on 16 May 1998. The next day, on the morning of 17 May 1998, he received a call from the Pakistan Army GHQ, Rawalpindi informing him to remain on stand-by for a meeting with the Prime Minister. He was thereafter summoned by the Prime Minister House, Islamabad where he went accompanied by Dr. Mubarakmand. The Prime Minister asked the PAEC Chairman for his opinion on the two points which were discussed in the DCC meeting of 15 May 1998. Dr. Ahmed told the Prime Minister that the decision to test or not to test was that of the Government of Pakistan. As far as the PAEC preparedness and capability was concerned, they were ready to do their duty as and when required to do so. The Prime Minister said that eyes of the world were focused on Pakistan and failure to conduct the tests would put the credibility of the Pakistan nuclear programme in doubt and would encourage India into embarking on a misadventure against Pakistan – a concern expressed by many quarters. The PAEC Chairman’s reply was, “Mr. Prime Minister, take a decision and, insha’Allah, I give you the guarantee of success,”. He was told to prepare for the tests but remain on stand-by for the final decision.

We know that the order to conduct the tests was given on 18 May 1998. Since the DCC meeting of 15 May 1998 proved inconclusive, it is believed that a more exclusive DCC meeting was held on either 16 or 17 May 1998 attended only by the Prime Minister, the Foreign Minister, the Finance Minister and the three Chiefs of Staff of the Army, Air Force and Navy. This meeting has never been officially acknowledged but it must have been held as neither the Prime Minister alone nor the Chief of the Army Staff alone could have made the decision to conduct the nuclear tests. The DCC was the only competent authority to decide on this matter, especially since the National Security Council (NSC), Pakistan’s apex security decision-making body and the National Command Authority (NCA), Pakistan’s nuclear command and control authority for its strategic nuclear forces, did not exist at that time. In this meeting, the two agenda points of the DCC meeting of 15 May 1998 were decided. Firstly, Pakistan would give a matching and befitting response to India by conducting nuclear tests of its own. Secondly, the task would be assigned to the PAEC, who were the best equipped and most experienced to carry out the tests.

On 18 May 1998, the Chairman of the PAEC was again summoned to the Prime Minister House where he was relayed the decision of the DCC. “Dhamaka kar dein” (“Conduct the explosion”) were the exact Urdu words used by the Prime Minister to inform him of the Government’s decision to conduct the nuclear tests. The PAEC Chairman went back to his office and gave orders to his staff to prepare for the tests and called for an urgent extraordinary meeting of the top PAEC executives, scientists and engineers. Simultaneously, GHQ and Air Headquarters (AHQ) issued orders to the relevant quarters in 12 Corps, Quetta, the National Logistics Cell (NLC), the Army Aviation Corps and No. 6 Air Transport Support (ATS) Squadron led by Group Captain Sarfraz Ahmad Khan at Chaklala Air Base respectively to extend the necessary support to the PAEC in this regard. The Civil Aviation Authority (CAA) also directed the national airline, PIA, to make available a Boeing 737 passenger aircraft at short notice for the ferrying of PAEC officials, scientists, engineers and technicians to Balochistan.

When news reached Dr. A.Q. Khan at KRL that the task had been assigned to PAEC and not KRL, he lodged a strong protest with General Jehangir Karamat. Dr. A.Q. Khan was upset, and rightly so. A man who is known as the “father” of Pakistan’s nuclear weapons programme deserved to be given more importance than he was, at least for protocol reasons if nothing else. The Army Chief, in turn, called the Prime Minister. Amongst the two, it was decided that KRL personnel, including Dr. A.Q. Khan, would also be involved in the nuclear test preparations and present at the time of testing alongside those of the PAEC.

In the meantime, PAEC convened a meeting to decide the modus operandi, quantity and size of the nuclear tests to be conducted. This meeting was chaired by Dr. Ishfaq Ahmed and attended by Dr. Samar Mubarakmand and other high-ranking executives, scientists and engineers of the PAEC. It was decided that since the Indian nuclear tests had presented Pakistan with an opportunity to conduct nuclear tests for the first time after 14 years of having conducted only cold tests, the maximum benefit should be derived from this opportunity. It was, therefore, decided, that multiple tests would be carried out of varying yields as well as the live testing of the triggering mechanisms. Since the five horizontal shaft tunnels at Ras Koh Hills and the single vertical shaft tunnel at Kharan had the capability to collectively host a total of six tests, therefore, it was resolved that six different nuclear devices of different designs, sizes and yields would be selected, all of which had been previously cold tested.

Immediately afterwards, began the process of fitness and quality checks of the various components of the nuclear devices and the testing equipment. A large but smooth logistics operation also got under way with the help of the Pakistan Army and Air Force. This operation involved moving men and equipment as well as the nuclear devices to the Chagai test sites from various parts of the country.

On 19 May 1998, two teams comprising of 140 PAEC scientists, engineers and technicians left for Chagai, Balochistan on two separate PIA Boeing 737 flights. Also on board were teams from the Wah Group, the Theoretical Group, the Directorate of Technical Development (DTD) and the Diagnostics Group. Some of the men and equipment were transported via road using NLC trucks escorted by the members of the Special Services Group (SSG), the elite commando force of the Pakistan Army and Pakistan Army Aviation AH-1 Cobra gunship helicopters.

Various support facilities were established at both the test sites, including instrumentation bunkers and observation posts. All the installations including the tunnel portals and the instrumentation and fire control cables leading into the tunnel shafts were camouflaged using canvass and net. The facilities were made to look like a small hamlet using adobe huts so as to deceive satellite surveillance. The tunnel portal itself was located inside an adobe hut. Barbed wire was placed around all the facilities so as to minimise the number of tracks and to keep pedestrian and vehicular movement on designated tracks. Vehicle tracks caused by incoming and outgoing trucks and jeeps were continuously erased by a team of soldiers assigned to the task. Support camps were established a few hundred yards away from Ground Zero at both the sites. These included lodging, food and water, restroom, shelter and communications facilities. These too were camouflaged. At Ras Koh, these support facilities were located directly south of the mountain in which the shafts had been bored.

The nuclear devices were themselves flown in semi-knocked down (SKD) sub-assembly form on two flights of PAF C-130 Hercules tactical transport aircraft from PAF Chaklala in northern Punjab to Dalbandin Airfield, situated in the Chagai District south-east of the Chagai Hills in Balochistan, escorted even within Pakistani airspace by four PAF F-16s armed with air-to-air missiles. At the same time, PAF F-7P air defence fighters, also armed with air-to-air missiles, were on CAP guarding the aerial frontiers of Pakistan against intruders. Both the nuclear devices (the bomb mechanism, the HMX explosive shields and casing) and the fissile material (the highly enriched uranium components) were divided into two consignments and flown separately on two independent flights of the Hercules. The PAEC did not want to put all its nuclear eggs in one basket in case something adverse was to happen to the aircraft. The security of the devices and the fissile material was so strict that that PAF F-16 escort pilots had been secretly given standing orders that in the unlikely event of the C-130 being hijacked or flown outside of Pakistani airspace, they were to shoot down the aircraft before it left Pakistan’s airspace. The F-16s were ordered to escort the C-130s to the Dalbandin airfield in Balochistan with their radio communications equipment turned off so that no orders, in the interim, could be conveyed to them to act otherwise. They were also ordered to ignore any orders to the contrary that got through to them during the duration of the flight even if such orders seemingly originated from Air Headquarters.

Once at the Dalbandin airfield south-east of the Chagai Hills, the sub-assembled parts of the nuclear devices were carefully offloaded from the aircraft and were separately taken in sub-assembled form to the test sites at Ras Koh Hills and Kharan presumably on Pakistan Army Aviation Mil Mi-17 helicopters. At Ras Koh Hills in Chagai, they were taken into the five ‘Zero Rooms’ located at the end of the kilometre long horizontal tunnels. Dr. Samar Mubarakmand personally supervised the complete assembly of all five nuclear devices. Diagnostic cables were thereafter laid from the tunnel to the telemetry. The cables connected all five nuclear devices with a command observation post 10 kilometres away. Afterwards, a complete simulated test was carried out by tele-command. This process of preparing the nuclear devices and laying of the cables and the establishment of the fully functional command and observation post took five days to complete.

On 25 May 1998, soldiers of the Pakistan Army’s 12 Corps arrived to seal the tunnel. They were supervised by engineers and technicians from the Pakistan Army Engineering Corps, the Frontier Works Organisation (FWO) and the Special Development Works (SDW). Dr. Samar Mubarakmand himself walked a total of 5 kilometres back and forth in the hot tunnels checking and re-checking the devices and the cables, which would be buried forever under the concrete. Finally, the cables were plugged into the nuclear devices. The process of the sealing the tunnels thereafter began with the mixing of the cement and the sand and their pouring into the tunnels. It took a total of 6,000 cement bags to seal the tunnel and twice the amount of sand.

The tunnels were sealed and plugged by the afternoon of 26 May 1998 and by the afternoon of 27 May 1998, the cement had completely dried out due to the excessive heat of the summer desert. After the engineers certified that the concrete had hardened and the site was fit for the tests it was communicated to the Prime Minister via the GHQ that the site was ready.

The date and time for Pakistan’s rendezvous with destiny was set for 3:00 p.m. on 28 May 1998.


Thursday, 28 May 1998 dawned with an air alert over all military and strategic installations of Pakistan. The PAF had earlier been put on red alert to respond to the remote but real possibility of a joint Indo-Israeli pre-emptive strike against its nuclear installations. Pakistan thought it fit to be safe rather than sorry. PAF F-16A and F-7P air defence fighters were scrambled from air bases around the country to remain vigilant and prepared for any eventuality.

Before twilight, the automatic data transmission link from all Pakistani seismic stations to the outside world was switched off.

At Chagai, it was a clear day. Bright, warm and sunny without a cloud in sight. There was a slight breeze. All personnel, civil and military, were evacuated from ‘Ground Zero’ except for members of the Diagnostics Group and the firing team. They had been involved in digging out and removing some equipment lying there since 1978.

Ten members of the team reached the Observation Post (OP) located 10-kilometres away from Ground Zero. The firing equipment was checked for one last time at 1:30 p.m. and prayers were offered. An hour later, at 2:30 p.m., a khaki-brown battle-camouflaged Pakistan Army Aviation Mil Mi-17 helicopter carrying the team of observers including PAEC Chairman, Dr. Ishfaq Ahmed, KRL Director, Dr. A.Q. Khan, and four other scientists from KRL including Dr. Fakhr Hashmi, Dr. Javed Ashraf Mirza (who later became Director, KRL on Dr. A.Q. Khan’s retirement from the post in March 2001), Dr. M. Nasim Khan and S. Mansoor Ahmed arrived at the site. Also accompanying them was a Pakistan Army team headed by Lt. Gen. Zulfikar Ali, Chief of the Combat Division.

At 3:00 p.m., a truck carrying the last lot of the personnel and soldiers involved in the site preparations passed by the OP. Soon afterwards, the all-clear was given to conduct the test as the site had been fully evacuated.

Amongst the 20 men present, one young man, Muhammad Arshad, the Chief Scientific Officer, who had designed the triggering mechanism, was selected to push the button. He was asked to recite “All Praise be to Allah” and push the button. At exactly 3:16 p.m. Pakistan Standard Time (P.S.T.), the button was pushed and Muhammad Arshad stepped from obscurity into history.

As soon as the button was pushed, the control system was taken over by computer. The signal was passed through the air-link initiating six steps in the firing sequence while at the same time bypassing, one after the other, each of the security systems put in place to prevent accidental detonation. Each step was confirmed by the computer, switching on power supplies for each stage. On the last leg of the sequence, the high voltage power supply responsible for detonating the nuclear devices was activated.

As the firing sequence passed through each level and shut down the safety switches and activating the power supply, each and every step was being recorded by the computer via the telemetry which is an apparatus for recording readings of an instrument and transmitting them via radio. A radiation-hardened television camera with special lenses recorded the outer surface of the mountain.

As the firing sequence continued through its stages, twenty pairs of eyes were glued on the mountain 10 kilometres away. There was deafening silence within and outside of the OP.

The high voltage electrical power wave simultaneously reached, with microsecond synchronization, the triggers in all the explosive HMX lenses symmetrically encircling the Beryllium/Uranium-238 (2) reflector shield and the ball of Uranium 235 (3) around the initiator core in all five devices.

When the electrical current ran through the wires to the lenses, an explosion was triggered in all five of the devices. Because of the symmetrical nature of the placement of the explosives, a spherically imploding shock wave was set off, instantly squeezing the Berylium/Uranium-238, the Uranium-235, and the initiator. The Berylium/Uranium-238 shield was pushed inward by the explosion, compressing the grapefruit-sized ball of Uranium-235 to the size of a plum in a microsecond. The Uranium-235 went from a subcritical to a supercritical density, and the initiator at the centre was similarly squeezed. The process of atoms fissioning – or splitting apart – began.

Neutrons released from the initiator began striking and bombarding the Uranium-235 at an extremely rapid rate. In each instance in which a neutron hit a Uranium atom, the atom split, creating two more neutrons, which in turn hit two more atoms, which split into four neutrons, which found four new atoms, thus splitting into eight neutrons, sixteen, thirty-two, sixty-four, one hundred and twenty-eight, two hundred and fifty-six and so on. This was the runaway chain reaction. With the splitting of each atom, a terrific amount of energy was released along with a variety of lethal atomic particles.

A short while after the button was pushed, the earth in and around the Ras Koh Hills trembled. The OP vibrated. Smoke and dust burst out through the five points where the nuclear devices were buried. The mountain shook and changed colour as the dust from thousands of years was dislodged from its surface. Its dark granite rock turning white as de-oxidisation occurred from the fierce radioactive forces operating from within. A huge thick cloud of beige dust then enveloped the mountain.

In the OP, shouts of “Nara-e-Takbeer” and “Allah-o-Akbar” (God is Great) went up.

The time-frame, from the moment when the button was pushed to the moment the detonations inside the mountain took place, was thirty seconds. For those in the OP, watching in pin-drop silence with their eyes focused on the mountain, those thirty seconds were the longest in their lives. It was the culmination of a journey which started over 20 years ago. It was the moment of truth and triumph against heavy odds, trials and tribulations. At the end of those thirty seconds lay Pakistan’s date with destiny.

Dr. A.Q. Khan later described the five devices as boosted fission devices. “One was a big bomb with a yield of about 30-35 kilotonnes…the others were small tactical weapons of low yield…they can be used on the battlefield”, he said.

The Pakistani Foreign Ministry would later describe it as “Pakistan’s finest hour”. Pakistan had become the world’s seventh nuclear power and the first nuclear weapons state in the Islamic World.

Two days later, on Saturday, 30 May 1998, Pakistan conducted its sixth nuclear test at 1:10 p.m. (P.S.T.) in the Kharan Desert. This was a miniaturized device giving a yield, which was 60% of the first tests, i.e. 18-20 kilotonnes. A crater now takes the place of what used to be a small hillock in the rolling desert, marking the ground zero of the nuclear test there.


(1) Burrows, William E. and Windrem, Robert, Critical Mass, Simon and Schuster, 1994, ISBN 0-671-74895-5.

(2) The exact content of the reflector shield is not known, but it is presumed to be either Beryllium or Uranium-238.

(3) It is widely accepted that the core was made up of Uranium-235 as opposed to Plutonium-239.

Article published in June 2000 issue of Defence Journal.