Like some of your family, my father's father was born in the mining village of Zarubek near Ostrava and emmigrated to the US in 1907. On his draft registration my Grandfather listed the village as "Polish Ostrava." The village no longer exists. On Google Maps I found a tram stop called Důl Zárubek(Zarubek Mine)to the east of Ostrava in the Silesian area. The mine was closed down a while ago, but I thought you might find this link to an online archive useful. I have been able to find my Grandfather and one of his cousins so far. The page headings are in German. Here is the link. http://matriky.archives.cz/
This is a link to a page with history of the Mine. It is in Czech, but if you paste the link into Google Translator you can get the gist of what it is saying... http://www.zdarbuh.cz/reviry/okd/dul-zarubek-v-ostrave/
Hope you enjoyed your voyage to Czech Republic. I hope to get there one day too.