They are no longer mined due to the fact that arsenic is rarely used in modern times. Originally, Arsenic wasused in a great variety of items, including paint pigments for the colors green and red, as well as fireworks and poison. Recently, arsenic has been considered "a pollutant" and "the next asbestos." The two minerals are found in veins of gold, silver, and other precious metals. When these metals are mined, the arsenic ores that are discarded get into the cround water and cause all kinds of horrible illnesses, including cancer. Many companies that mine these metals, especially in the western US, are very concerned about the issue. Recently, someone invented a device that uses the sun's UV rays to decompose Arsenic into its less toxic forms, which could pottentially save companies millions of dollars. It uses only water and natural sunlight, which are much cheaper than other methods of removing arsenic.
The only major modern uses for arsenic are poison, which by now is mostly accidental, and for collectors' samples. Larger samples of both Orpiment and Realgar can be quite valuable, especially if they are crystaline. Orpiment is almost always amorphous(without crystal form)and yellow, and realgar occasionally forms tabular red crystals. It's actually very pretty if you have a good sample. The Chinese used to carve it. However, very few of those carvings have survived because when you expose Orpiment and Realgar to light, they decompose, or break down.