mintage = number of coins struck
in belgium we have 2 official languages : dutch and french (okay, some speak german), so most coins were struck with flemish or french country name : BELGIE or BELGIQUE. Few (commemorative ) coins are BELGIEN (german)
coin value is effected by rarity and quality of the coin. The fewer coins were struck, the higher the price. The better it looks, the higher the price. Coin grading is not easy, and I can't learn you in a few lines. Here you can find more info :
http://www.acoin.com/grading.htm
Prices I mentioned are in euro, market value is is 40-60% of catalog value.
Greetings
Tony