Mixer trucks in Greater Seoul set to stop operations June 8

Pyeongtaek, Yongin semiconductor sites face supply disruption

Union status dispute and direct builder negotiations add complications

Ready-mix concrete mixer trucks sit idle as operators in Greater Seoul announce a full work stoppage beginning June 8. [Yonhap]
Ready-mix concrete mixer trucks sit idle as operators in Greater Seoul announce a full work stoppage beginning June 8. [Yonhap]

Ready-mix concrete transport operators in Greater Seoul are set to halt all operations June 8, threatening to disrupt construction at some of South Korea's most critical semiconductor sites. The stoppage could cut concrete supply to Samsung Electronics' Pyeongtaek campus and SK Hynix's Yongin cluster, raising concerns that the labor dispute could ripple into the broader semiconductor supply chain. Concrete producers say they have refused to enter negotiations partly because doing so would amount to recognizing the union's legal status.

According to the ready-mix concrete industry and the National Ready-Mix Concrete Transport Workers' Union, a strike vote held May 27 and 28 drew 7,326 of 7,517 Greater Seoul union members, with 6,603 — or 87.8 percent — voting in favor of a walkout beginning June 8. The union called on manufacturers to abandon what it described as a tactic of hiding behind regional bargaining and engage immediately in unified negotiations. "Responsibility for all industrial disruption caused by avoiding negotiations lies with the manufacturers," the union said.

Producers are taking an equally hard line. An industry official said the sector is treating the strike as effectively already under way and is exploring contingency measures. "Drivers are negotiating from the position that their past income levels must be maintained even if workloads fall," the official said. "The same pattern has repeated for years. This year's strike will play out the same way."

Negotiations elsewhere have made some progress. In Daejeon, a 5.9 percent increase — raising the per-trip transport fee from 76,500 won (about $55) to 81,000 won — was finalized in May. Busan averted a strike after a tentative agreement passed a membership vote on May 21; that deal calls for annual fee increases of 3,000 won per trip and a 3 percent annual rise for owner-operator members. Greater Seoul, however, is heading in the opposite direction. The union affiliated with the Federation of Korean Trade Unions recently sent formal notices of negotiation breakdown and impending work stoppage to construction companies and job sites.

Collective action by ready-mix concrete transport operators is not new. An 8-to-5 operating-hours rule was introduced in 2016, followed by a 66-day work stoppage in Ulsan in 2019, 15-day stoppages in Busan and South Gyeongsang Province and a 10-day halt in Gwangju and South Jeolla Province in 2020, the introduction of Saturday rest days in 2021, a refusal to operate in Seoul's historic city center over transport fee demands in 2022, a strike over fee increases in 2024, and a fee dispute in Cheonan and Asan in 2025.

What makes this year's Greater Seoul dispute particularly serious is that Samsung Electronics and SK Hynix semiconductor factory construction sites fall directly within the affected zone. Ready-mix concrete is a core construction material with no practical substitute on site; delays in pouring schedules cascade through subsequent work phases. The cost of schedule overruns at semiconductor fabrication plants is far greater than at ordinary construction sites. Industry officials say transport operators are using the national semiconductor construction sites — including Samsung Electronics' Pyeongtaek campus and SK Hynix's Yongin cluster — as leverage to push for higher unit prices.

Transport operators at the Samsung Electronics Pyeongtaek campus are reportedly demanding 1.5 million won per day on the condition of four trips on Saturdays. Samsung C&T reportedly pursued the installation of on-site batching plants to compress the construction schedule but abandoned the plan after operators objected. "For mega construction projects, installing an on-site batching plant is standard practice," an industry official said. "But at both the Yongin and Pyeongtaek sites, operator opposition has blocked most of those installations."

The fuel cost structure is also a point of contention. Ready-mix concrete companies in Greater Seoul calculate fuel reimbursements to mixer truck drivers using a reference fuel consumption rate of 0.58 liters per kilometer. The actual fuel consumption of mixer trucks, however, is around 0.45 liters per kilometer, according to industry figures. Drivers effectively pocket the difference as additional income.

Under a scenario of 80 trips per month at 30 kilometers per trip and a diesel price of 1,600 won per liter, the fuel cost borne by the concrete company comes to roughly 2.22 million won a month, while actual fuel consumption costs around 1.72 million won — leaving a gap of about 490,000 won that flows to the transport operator. If the diesel price rises to 1,800 won per liter, that gap widens to 562,000 won, meaning higher fuel prices simultaneously increase the burden on manufacturers and the windfall for drivers.

There are also concerns that collective bargaining demands will grow following the enactment of the so-called Yellow Envelope Act. In February, the Seoul Administrative Court ruled that transport operators qualify as workers under the Trade Union Act, and a union establishment certificate was issued in March. That first-instance ruling is currently under appeal, however. In contrast, both the Regional Labor Relations Commission and the National Labor Relations Commission ruled in 2024 that mixer truck drivers do not qualify as workers under the Trade Union Act.

The question of who constitutes a legitimate bargaining party is central to why concrete producers have refused to negotiate in Greater Seoul. An industry official argued that entering talks while the appeal is pending would amount to recognizing the union's legal status. The union countered that courts and the government have already affirmed its status, yet producers continue to refuse all engagement.

Transport operators may also move to demand direct price negotiations with construction companies — the primary contractors — bypassing ready-mix concrete manufacturers entirely. At the Samsung Electronics Pyeongtaek site and the SK Hynix Yongin semiconductor factory site, operators are said to have already negotiated transport fees directly with construction companies, with manufacturers only notified of the agreed rates after the fact.


hong@heraldcorp.com