Society argues Kaipara Harbour should supply sand needs MHRS legal representative James Carnie and Richard Bull. A map showing Kaipara’s proposed consent area in hatched red. The Mangawhai Harbour Restoration Society (MHRS) argued that controversial sand mining near Pakiri should be shifted to the Kaipara Harbour or substituted for other sources at a hearing in the Warkworth Town Hall last week. The hearing comes in the wake of Kaipara Ltd’s application to renew its consent to extract two million cubic metres of sand offshore from Pakiri and Mangawhai over 20 years. It contends that Pakiri’s sand is required to prevent a shortage of supply for the production of concrete in the Auckland market.