Peruvian surveyor Raidis Miranda said he vividly remembers his recent helicopter trip with experts from China Railway No 4 Engineering Group Co Ltd to map out a 46-kilometer highway in southern Peru.

He was invited to the mountainous region in May to be part of a mapping expedition meant to overcome such obstacles as complex terrain, landslides and harsh weather.

As they arrived, the Mi-17 military transport helicopter touched down on a flat, highland area. He and other participants got off the aircraft to prepare for their work in the Arequipa region.

The highway will link the towns of Andamayo and Ayo, and is expected to slash travel time for locals from six hours to 40 minutes, said Xiong Hongqing, project manager at CREC4 Municipal Engineering, which is building the highway.

"Going deep into the work site helped the surveyors get accurate data, laying a solid foundation for the job, including formulating and revising construction plans," Miranda said. "The whole operation, though requiring a lot of hard work, was very successful and necessary.

"In Peru, it is very rare to use helicopters for surveying and mapping work. CREC4's way of doing that is quite amazing," he added.

Construction of the highway got underway in February and is expected to be completed in January 2024, Xiong said. The helicopter trip in May was to survey the middle section of the highway, he said.

The road, designed to be 6 meters wide and rise 4,900 meters above sea level at its highest point, will traverse deep mountain canyons. The challenges are huge. One part of the road is in an area of very steep terrain, along cliffs facing the ocean, and access is quite difficult for the builders, vehicles and machinery, Xiong said.

Conditions are harsh in the hot, arid area, which features strong winds that often pick up sand, while the natural environment is fragile, he said.

"Working among such inaccessible barren slopes and mountains is beyond words," Xiong said. "You have to be careful where you step for fear of slipping down a deep cliff.

"But the highway will play a key role in enhancing the public's wellbeing, improving transportation and boosting local social and economic development."

Xiong encouraged managers to examine and reexamine possible answers to challenges in order to find the best way to do a complete job on the survey. After coordinating with different groups, the project department established a field team composed of Chinese professionals and Peruvian engineers.

The helicopter enabled them to move surveyors, supervisors and much-needed materials and equipment into the hinterland. Planners marked locations for five relatively flat campsites along the planned highway for the party. CREC4 also provided medical and security personnel.

Jesus Monje, a Peruvian engineer joining the expedition, said: "The Chinese builders were eager to work with our engineering staff. In the early hours each day, they set off to the work site, making the most of their help and working to eliminate obstacles. They are providing a great deal of assistance and playing a key role."

For CREC4 staff, the harsh conditions such as those in the mountains of Peru are not unfamiliar. In their overseas operations in nearly 20 countries, including Angola, Ethiopia, Mongolia, Indonesia, Bangladesh and Costa Rica, challenges abound, according to Song Heng, a CREC4 publicity official.

CREC4 First Engineering's project in the area of the Chebera Churchura National Park in southwestern Ethiopia is to build a VIP lodge, a 115-km road and bridges.

"We have to fight against damp heat, mosquitoes, malaria and other challenges during our construction work," said He Liming, CREC4 First Engineering's manager for Angola and Ethiopia operations. "We have had to overcome every difficulty," He said.

Song said the biggest difficulty facing CREC4 builders overseas is that construction materials and daily necessities must be shipped from home, as there are no support industries or materials for them abroad.

CREC4 Municipal Engineering staffers stationed in Angola sometimes had to plant their own vegetables as they built the facilities where they would live and work, he said.

Yang Baokui, engineering chief for CREC4 Municipal Engineering's project department in Angola during the construction of the Ekuma Phase-II new city housing project in Ondjiva, Cunene province, has been stationed there since October 2015.

Yang said, in more than six years, he had spent only one Chinese Spring Festival－an important time for family reunions－with his family back home, and his wedding ceremony has been repeatedly delayed due to COVID-19 flight disruptions.