Andrew Su, CEO at brokerage Compass Global Markets said the average cost of producing gold in Australia, home to some of the world's biggest gold miners, has jumped from $500 an ounce in 2007 to over $1,000 an ounce this year.
Persons (plural) is a very formal word. We only use it in rather legalistic contexts: [notice in a lift] Any person or persons found in possession of illegal substances will be prosecuted.
refers to the person or people being spoken or written about (he, she, and it for singular, they for plural). The person of a pronoun is also demonstrated in the chart Cases of the Personal Pronouns. As you will see there, each person can change form, reflecting its use within a sentence.