A JOBLESS man snatched cash from a petrol station after throwing sand into the cashier's eyes, the District Court heard yesterday. Chan Wai-por, 23, pleaded guilty to the May 30 robbery of the Mobil petrol station in Po Lam Road North, Tseung Kwan O. Sentencing Chan to 40 months' jail, Judge Wong said robbery was an offence which warranted a lengthy custodial sentence. Force had been applied in the sense that Chan had used sand as a weapon. He took account of Chan's guilty plea and that the money had been recovered. Prosecutor Agnes Chan said the cashier, Yau Wai-ping, was counting the day's takings at 11.16 pm in the presence of Ngai Ying-fai, the cashier on the next shift. Ms Yau was dividing banknotes when Chan approached the counter. Chan took a handful of sand from his shorts pocket, threw it into Ms Yau's eyes, and then grabbed $13,000. Ms Ngai shouted ''robbery'' and the defendant fled, but did not get very far as police grabbed him. Under caution, Chan told the police he had stolen the money to buy drugs. Ms Yau was sent to hospital for treatment. Defence solicitor Joseph Pang said his client had been ordered into a drug treatment centre after being convicted of a drug offence last month.