Aug. 28, 2018. CDRRMO received information from Tina-an Barangay Captain Teodoro Cantal that cracks were noticed on some areas of Sitios Tagaytay and Sindulan, damaging the floor of some houses.
Aug. 29, 2018. The mayor ordered a joint inspection by representatives of DENR-MGB, Apo Land and Quarry Corp. (ALQC) and the City Government. Chiong issued a cease-and-desist order (CDO) to ALQC.
Aug. 30, 2018. The mayor issued a memo directing the city administrator to meet with residents to inform them on the issuance of a CDO on quarry activities, awaiting clearance of DENR-MGB. ALQC assured the City that it will comply with the CDO and said that it has relocated some residents to ensure their safety. ALQC told the City about the DENR-MGB's assessment, which found that the cracks had nothing to do with its quarry operation but was caused by natural earth movement.
Sept. 4, 2018. DENR sent a letter to Mayor Kristine Chiong saying that the cracks and fissures are caused by a natural phenomenon. The DENR-MGB granted clearance to ALQC to continue its usual activity at the site.
Sept. 5, 2018. ALQC sent a letter to Chiong confirming that the cracks and fissures had nothing to do with their operations.
Sept. 6, 2018. City Government lifted CDO. ALQC was told to submit a written report to the mayor every 15th of the month. Further, evacuation and relocation plan must be submitted within five days.
Sept. 11, 2018. ALQC informed the mayor of the worsening cracks in the area, from 3mm on Aug. 31 at the Main Tower-North to 35 mm on Sept. 11. ALQC said it had not started mining operations yet.
Sept. 13, 2018. City sent a letter to DENR requesting for a re-evaluation of the situation and conduct of a technical assessment and inspection.
Sept. 19, 2018. The City sent a letter to National Grid Corp. of the Philippines, whose towers are in Sitio Tagaytay, informing them that based on monitoring, the horizontal displacement, cracks and fissures found on the site continue to increase. This prompted the evacuation of families in the area.
Sept. 20, 2018. At 6 a.m., a landslide occurred in Sitio Tagaytay, burying alive close to 100 individuals in Sitio Sindulan.