Pat the beef roast dry with paper towels and season evenly with the sea salt and black pepper.
Heat the olive oil in a large skillet over medium-high heat and sear the beef until a golden-brown crust forms on all sides.
Layer the chopped onion, carrots, potato, and celery at the bottom of the slow cooker insert.
Place the seared beef roast directly on top of the bed of vegetables.
In a small bowl, whisk together the beef broth, tomato paste, and minced garlic, then pour the mixture over the roast.
Nestle the fresh rosemary and thyme sprigs into the liquid surrounding the beef.
Cover the slow cooker and cook on the low setting for 8 hours or the high setting for 4 hours until the beef is fork-tender.
Remove the herb sprigs and serve the roast sliced with the softened vegetables and savory pan juices.