Prepare the pork: Combine the brown sugar, paprika, coriander, onion powder, garlic powder, mustard powder, 1 tablespoon salt and 1/4 teaspoon pepper in a large baking dish. Pierce both sides of the pork chops with a paring knife (about 12 times per side). Add the pork chops to the dish, turning to coat with the spice rub. Cover and refrigerate at least 4 hours or overnight.
Make the sauce: Combine the vinegar, preserves, garlic, Worcestershire sauce, mustard powder, red pepper flakes and 3/4 teaspoon salt in a medium saucepan. Bring to a boil, then reduce the heat to medium low and simmer, whisking occasionally, until the sauce thickens slightly, about 8 minutes; let cool completely. Transfer 1/4 cup of the sauce to a separate bowl for basting. Set aside the remaining sauce for serving.
Remove the pork from the refrigerator about 30 minutes before grilling. Preheat a grill to medium and lightly brush the grates with vegetable oil. Transfer the pork chops to the grill, cover and cook until lightly marked, about 4 minutes. Flip the pork chops and baste with the sauce; cover and cook 3 more minutes. Uncover and continue cooking, flipping and basting the pork chops every 2 minutes, until they are golden and well marked, about 8 more minutes. Transfer to a cutting board and let rest 5 minutes.
Meanwhile, brush the peaches lightly with vegetable oil and place cut-side down on the grill. Cover and grill until marked, 1 to 2 minutes per side. Serve the pork chops with the grilled peaches and the reserved sauce.
These are the most common kind of pork chops. They come from the center of the loin and tend to be lean.