Verifiability/reliability: Strong, from a verified WeChat public security account, though the numbers given are estimates by the author
This is a post from Xinyang Detention Center WeChat account. It has since been deleted, see here for the archived copy. As of now, the QR code in the linked article still resolves to the official account of the Xinyang Detention Center. It describes a speech given by one officer, Li Chuanwei, dispatched to Xinjiang for three months (part of a team of them from Xinyang, to help alleviate the severe shortage of security personnel as a result of the Strike Hard campaign) in Chira (or Qira) County.
The post corroborates another account of a Xinjiang Aid team in Chira County who arrived a few months after the Xinyang rotation of officers were there. It's also notable for its cop whininess and some numbers from the speaker, namely, the "over 400 meters" walked by police officers taking detainees to some sort of hearing or interrogation and the total distance officers had to walk daily, "up to or above 30 kilometers". Taking this with a grain of salt, of course, we can take a guess at detention numbers: if we somewhat arbitrarily assume the distance to be 450 meters per trip and 30 kilometers per day, that’d be just under 67 people per day. If we say 410 meters and 36 kilometers, it'd be around 88. Over a three-month period, that's between 8,000 to 10,500 people, assuming individuals do not repeat trips. (The population of Chira County was 166,735 (163,814 non-Han) in 2015, according to government statistics, although the post by Li says it has since dropped below 160,000.)
The exact nature of this detention center is not entirely clear. Given that this spike in detainees coincides with the renewed 2017 Strike Hard campaign, we can reasonably assume the two phenomena are related. Per the Xinjiang Documentation Project, the detention center in the Xinjiang context "functions as an interrogation center where detainees are held until they are sent either to prison or camps. They are not considered prisons."
Xinyang City Detention Center launches "Learning from the 19th CPC National Congress, Carrying Forward the Spirit of Xinjiang Aid" special event
In the afternoon of December 18, the Xinyang Prefecture-Level City Detention Center held a meeting for all police, auxiliary police, and support staff, launching the “Study the 19th Party Congress and Promote the Spirit of Xinjiang Aid” special event. Comrade Li Chuanwei, a Xinjiang Aid police officer, delivered lecture remarks for the event, and the Center’s director, comrade Zhang Duncheng, called for [everyone] to study comrade Li Chuanwei’s remarks.
Li Chuanwei presented on this period of Xinjiang Aid work. All Xinjiang Aid officers made full use of the Henan officers’ proud tradition and excellent style of work—“especially enduring of hardship, especially able to fight, and especially devoted”—[they] resolutely obeyed the leadership of the [Xinjiang] Aid detention center, strictly abided by the discipline of Xinjiang Aid work and their personal discipline, strictly maintained by the work system of the detention center, working closely with the local police, learning from each other, complementing each other's strengths, and improving together, successfully completing the Xinjiang Aid mission.
In Chira County during this period, comrade Li Chuanwei proactively volunteered himself to work at posts in the most dangerous, arduous, intensive places of the center, where contact with security threat criminals was closest and detentions were frequent. As the locality persevered in the Strike Hard campaign, there were thus large numbers of those locked up. Every day hundreds detained, investigated [提讯],* and met with. With their Xinjiang battlemates in groups of three, every day they endlessly went back and forth between the prison and detention hall. Every person detained and escorted took over 400 meters; every day, [the police] walked up to 30 kilometers or more, getting blisters on their feet. They regularly skipped meals because they were so busy, not even stopping for rice. Because there are so many detainees, foul smells mingled about, nauseating and unbearable. There were no breaks during work. Their backs ached at the end of the day, and they kept on fighting the next day, covered in grime and exhausted mentally and physically. Yet no one complained a bit.
* 提讯 is often translated as 'bring to trial', but can also refer to any sort of inquest or investigation (c.f. 审讯 in 警方正在审讯嫌疑犯 police are interrogating the suspect, not *police are holding trial for the suspect). Given that mass internment/reeducation in Xinjiang is extrajudicial, it would appear these are not trials in a formal sense. Even if they are formally considered trials, the fact that there can be so many in one day indicates they do not represent meaningful due process.
Li Chuanwei also spoke of the great sandstorms of Xinjiang and its dry air; the linguistic, cultural, and dietary differences compared to inland China; the jetlag and two-hour schedule timezone difference with the inland;* for all these the police endured a long process of adjustment. Over three months, [he] experienced first diarrhea, tonsillitis, stomachaches and then vertigo. All [he] could do under the circumstances was merely take some medicine, as there was simply no time to go to the hospital for diagnosis. [He] frequently felt as if his body had been hollowed out, unbalanced, and [he] even had the impulse to become a “deserter” because of the intensity of the work, the great psychological pressure, and the food he was unaccustomed to. But when [he] remembered the sacred mission [he] bore, [he] thought of the ardent expectations, the exhortations and telephone inquiries from leaders and comrades at all levels, the condolences to [our?] family members and other such [instances of] meticulous care, [he] quickly calmed down, adjusted [his] mentality, overcame all difficulties, and kept on persisting. Hearing this, all the sitting staff were moved to tears. * All of China is in one timezone. This means that in Xinjiang, sunset occurs some parts of the year around midnight, and sunrise around 10am.
Finally, the director, Comrade Zhang Duncheng, called on everyone to earnestly study and implement the spirit of the 19th National Congress of the Communist Party of China, and at the same time, [called on the institute] to quickly surge in fervor to learn from Comrade Li Chuanwei, cherish the safe, stable and regular working environment of our inland prisons, promote the "loyalty, dedication, devotion, and responsibility” of the "Spirit of Xinjiang Aid" of "Dedication and Responsibility", work in peace of mind in the prisons, and continuously push the work of the Xinyang Detention Center to a new level.