文件中的PHP邮件收件人和邮件间隔

我正在尝试做一个php,将发送电子邮件每60秒从一个收件人 电子邮件。但我不知道该怎么做。

emails.txt: email1@google.com, email2@google.com, email3@google.com

同一条信息将发送给所有3个收件人,但每次发送之间间隔60秒。

<?php>
$file = fopen("emails.txt",  "r") or die("Unable to open file!");
        //while(!feof($file)){
        $line = fgets($file);
            $to = $line;
            
            $config['mailtype'] = "html";

            $this->email->initialize($config);
            
             $subject = "Subject";

             $message = 'This is test message';

             $header = "From:TESTE \r\n";
             $header .= "MIME-Version: 1.0\r\n";
             $header .= "Content-type: text/html\r\n";

             $retval = mail ($to,$subject,$message,$header);
             
             
            foreach($to as $value) { 
            $result = mail($value, $subject, $message, $header); 
            sleep(60);
            } 

             if( $retval == true ) {
                echo "Message sent successfully...";
             }else {
                echo "Message could not be sent...";
         }


        fclose($file);
        }
</php>