Keystone Filler has been in business since 1873. We've grown by maintaining the philosophy we began with: flexibility and cooperation in meeting customer needs. As processing technology grows, mineral fillers and extenders must adapt to new techniques. We experiment with various materials and compositions until we find the best, but most economical, product for each customer's application.

Although our network of raw materials supply is extensive, we constantly explore ways to foresee and minimize shortages. You can count on Keystone as a reliable source to ensure uninterrupted production for all our customers. (Susquehanna Metal Products also produces metal bins, hoppers, ducting, dust filters, and related material handling equipment.)

The old saying "Customer's first" reflects our approach at Keystone. To give personalized customer service, to maintain flexibility and cooperation in meeting unexpected needs, to preserve confidentiality - these guidelines all work towards producing quality work...and therefore keeping satisfied customers. So, we will respond efficiently to changes of "unscheduled demands"; we will meet the unexpected because we assumer it's a natural part of our business. And we plan accordingly - both in quality control and in making sure we stay versatile enough to meet your needs, no matter how specialized.

Customized mineral processing at Keystone means just that: any process; alone, or in combination with any other process. We'll perform one or more of the specific processing stages, or we'll take your materials through the entire customized processing sequence - even adding our own materials if required. And throughout the process, our quality control lab monitors every step to ensure Keystone has met your exact specifications.